Merged master

docs/source/_static/js/custom.js

@@ -1,10 +1,11 @@
 // These two things need to be updated at each release for the version selector.
 // Last stable version
-const stableVersion = "v3.0.2"
+const stableVersion = "v3.1.0"
 // Dictionary doc folder to label
 const versionMapping = {
     "master": "master",
-    "": "v3.0.0/v3.0.1/v3.0.2 (stable)",
+    "": "v3.1.0 (stable)",
+    "v3.0.2": "v3.0.0/v3.0.1/v3.0.2 (stable)",
     "v2.11.0": "v2.11.0",
     "v2.10.0": "v2.10.0",
     "v2.9.1": "v2.9.0/v2.9.1",
@@ -24,6 +25,7 @@ const versionMapping = {
 // The page that have a notebook and therefore should have the open in colab badge.
 const hasNotebook = [
     "benchmarks",
+    "custom_datasets",
     "multilingual",
     "perplexity",
     "preprocessing",

docs/source/conf.py

@@ -26,7 +26,7 @@ author = u'huggingface'
 # The short X.Y version
 version = u''
 # The full version, including alpha/beta/rc tags
-release = u'3.0.2'
+release = u'3.1.0'
 
 
 # -- General configuration ---------------------------------------------------
@@ -76,7 +76,8 @@ exclude_patterns = [u'_build', 'Thumbs.db', '.DS_Store']
 pygments_style = None
 
 # Remove the prompt when copying examples
-copybutton_prompt_text = ">>> "
+copybutton_prompt_text = r">>> |\.\.\. "
+copybutton_prompt_is_regexp = True
 
 # -- Options for HTML output -------------------------------------------------
 

docs/source/custom_datasets.rst

@@ -0,0 +1,715 @@
+Fine-tuning with custom datasets
+================================
+
+.. note::
+
+    The datasets used in this tutorial are available and can be more easily accessed using the
+    `🤗 NLP library <https://github.com/huggingface/nlp>`_. We do not use this library to access the datasets here
+    since this tutorial meant to illustrate how to work with your own data. A brief of introduction can be found
+    at the end of the tutorial in the section ":ref:`nlplib`".
+
+This tutorial will take you through several examples of using 🤗 Transformers models with your own datasets. The
+guide shows one of many valid workflows for using these models and is meant to be illustrative rather than
+definitive. We show examples of reading in several data formats, preprocessing the data for several types of tasks,
+and then preparing the data into PyTorch/TensorFlow ``Dataset`` objects which can easily be used either with
+:class:`~transformers.Trainer`/:class:`~transformers.TFTrainer` or with native PyTorch/TensorFlow.
+
+We include several examples, each of which demonstrates a different type of common downstream task:
+
+  - :ref:`seq_imdb`
+  - :ref:`tok_ner`
+  - :ref:`qa_squad`
+  - :ref:`resources`
+
+.. _seq_imdb:
+
+Sequence Classification with IMDb Reviews
+-----------------------------------------
+
+.. note::
+
+    This dataset can be explored in the Hugging Face model hub (`IMDb <https://huggingface.co/datasets/imdb>`_), and can
+    be alternatively downloaded with the 🤗 NLP library with ``load_dataset("imdb")``.
+
+In this example, we'll show how to download, tokenize, and train a model on the IMDb reviews dataset. This task
+takes the text of a review and requires the model to predict whether the sentiment of the review is positive or
+negative. Let's start by downloading the dataset from the
+`Large Movie Review Dataset <http://ai.stanford.edu/~amaas/data/sentiment/>`_ webpage.
+
+.. code-block:: bash
+
+    wget http://ai.stanford.edu/~amaas/data/sentiment/aclImdb_v1.tar.gz
+    tar -xf aclImdb_v1.tar.gz
+
+This data is organized into ``pos`` and ``neg`` folders with one text file per example. Let's write a function that can
+read this in.
+
+.. code-block:: python
+
+    from pathlib import Path
+
+    def read_imdb_split(split_dir):
+        split_dir = Path(split_dir)
+        texts = []
+        labels = []
+        for label_dir in ["pos", "neg"]:
+            for text_file in (split_dir/label_dir).iterdir():
+                texts.append(text_file.read_text())
+                labels.append(0 if label_dir is "neg" else 1)
+
+        return texts, labels
+
+    train_texts, train_labels = read_imdb_split('aclImdb/train')
+    test_texts, test_labels = read_imdb_split('aclImdb/test')
+
+We now have a train and test dataset, but let's also also create a validation set which we can use for for
+evaluation and tuning without training our test set results. Sklearn has a convenient utility for creating such
+splits:
+
+.. code-block:: python
+
+    from sklearn.model_selection import train_test_split
+    train_texts, val_texts, train_labels, val_labels = train_test_split(train_texts, train_labels, test_size=.2)
+
+Alright, we've read in our dataset. Now let's tackle tokenization. We'll eventually train a classifier using
+pre-trained DistilBert, so let's use the DistilBert tokenizer.
+
+.. code-block:: python
+
+    from transformers import DistilBertTokenizerFast
+    tokenizer = DistilBertTokenizerFast.from_pretrained('distilbert-base-uncased')
+
+Now we can simply pass our texts to the tokenizer. We'll pass ``truncation=True`` and ``padding=True``, which will
+ensure that all of our sequences are padded to the same length and are truncated to be no longer model's maximum
+input length. This will allow us to feed batches of sequences into the model at the same time.
+
+.. code-block:: python
+
+    train_encodings = tokenizer(train_texts, truncation=True, padding=True)
+    val_encodings = tokenizer(val_texts, truncation=True, padding=True)
+    test_encodings = tokenizer(test_texts, truncation=True, padding=True)
+
+Now, let's turn our labels and encodings into a Dataset object. In PyTorch, this is done by subclassing a
+``torch.utils.data.Dataset`` object and implementing ``__len__`` and ``__getitem__``. In TensorFlow, we pass our input encodings and
+labels to the ``from_tensor_slices`` constructor method. We put the data in this format so that the data can be
+easily batched such that each key in the batch encoding corresponds to a named parameter of the
+:meth:`~transformers.DistilBertForSequenceClassification.forward` method of the model we will train.
+
+.. code-block:: python
+
+    ## PYTORCH CODE
+    import torch
+
+    class IMDbDataset(torch.utils.data.Dataset):
+        def __init__(self, encodings, labels):
+            self.encodings = encodings
+            self.labels = labels
+
+        def __getitem__(self, idx):
+            item = {key: torch.tensor(val[idx]) for key, val in self.encodings.items()}
+            item['labels'] = torch.tensor(self.labels[idx])
+            return item
+
+        def __len__(self):
+            return len(self.labels)
+
+    train_dataset = IMDbDataset(train_encodings, train_labels)
+    val_dataset = IMDbDataset(val_encodings, val_labels)
+    test_dataset = IMDbDataset(test_encodings, test_labels)
+    ## TENSORFLOW CODE
+    import tensorflow as tf
+
+    train_dataset = tf.data.Dataset.from_tensor_slices((
+        dict(train_encodings),
+        train_labels
+    ))
+    val_dataset = tf.data.Dataset.from_tensor_slices((
+        dict(val_encodings),
+        val_labels
+    ))
+    test_dataset = tf.data.Dataset.from_tensor_slices((
+        dict(test_encodings),
+        test_labels
+    ))
+
+Now that our datasets our ready, we can fine-tune a model either with the 🤗
+:class:`~transformers.Trainer`/:class:`~transformers.TFTrainer` or with native PyTorch/TensorFlow. See
+:doc:`training <training>`.
+
+.. _ft_trainer:
+
+Fine-tuning with Trainer
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+The steps above prepared the datasets in the way that the trainer is expected. Now all we need to do is create a
+model to fine-tune, define the :class:`~transformers.TrainingArguments`/:class:`~transformers.TFTrainingArguments`
+and instantiate a :class:`~transformers.Trainer`/:class:`~transformers.TFTrainer`.
+
+.. code-block:: python
+
+    ## PYTORCH CODE
+    from transformers import DistilBertForSequenceClassification, Trainer, TrainingArguments
+
+    training_args = TrainingArguments(
+        output_dir='./results',          # output directory
+        num_train_epochs=3,              # total number of training epochs
+        per_device_train_batch_size=16,  # batch size per device during training
+        per_device_eval_batch_size=64,   # batch size for evaluation
+        warmup_steps=500,                # number of warmup steps for learning rate scheduler
+        weight_decay=0.01,               # strength of weight decay
+        logging_dir='./logs',            # directory for storing logs
+        logging_steps=10,
+    )
+
+    model = DistilBertForSequenceClassification.from_pretrained("distilbert-base-uncased")
+
+    trainer = Trainer(
+        model=model,                         # the instantiated 🤗 Transformers model to be trained
+        args=training_args,                  # training arguments, defined above
+        train_dataset=train_dataset,         # training dataset
+        eval_dataset=val_dataset             # evaluation dataset
+    )
+
+    trainer.train()
+    ## TENSORFLOW CODE
+    from transformers import TFDistilBertForSequenceClassification, TFTrainer, TFTrainingArguments
+
+    training_args = TFTrainingArguments(
+        output_dir='./results',          # output directory
+        num_train_epochs=3,              # total number of training epochs
+        per_device_train_batch_size=16,  # batch size per device during training
+        per_device_eval_batch_size=64,   # batch size for evaluation
+        warmup_steps=500,                # number of warmup steps for learning rate scheduler
+        weight_decay=0.01,               # strength of weight decay
+        logging_dir='./logs',            # directory for storing logs
+        logging_steps=10,
+    )
+
+    with training_args.strategy.scope():
+        model = TFDistilBertForSequenceClassification.from_pretrained("distilbert-base-uncased")
+
+    trainer = TFTrainer(
+        model=model,                         # the instantiated 🤗 Transformers model to be trained
+        args=training_args,                  # training arguments, defined above
+        train_dataset=train_dataset,         # training dataset
+        eval_dataset=val_dataset             # evaluation dataset
+    )
+
+    trainer.train()
+
+.. _ft_native:
+
+Fine-tuning with native PyTorch/TensorFlow
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+We can also train use native PyTorch or TensorFlow:
+
+.. code-block:: python
+
+    ## PYTORCH CODE
+    from torch.utils.data import DataLoader
+    from transformers import DistilBertForSequenceClassification, AdamW
+
+    device = torch.device('cuda') if torch.cuda.is_available() else torch.device('cpu')
+
+    model = DistilBertForSequenceClassification.from_pretrained('distilbert-base-uncased')
+    model.to(device)
+    model.train()
+
+    train_loader = DataLoader(train_dataset, batch_size=16, shuffle=True)
+
+    optim = AdamW(model.parameters(), lr=5e-5)
+
+    for epoch in range(3):
+        for batch in train_loader:
+            optim.zero_grad()
+            input_ids = batch['input_ids'].to(device)
+            attention_mask = batch['attention_mask'].to(device)
+            labels = batch['labels'].to(device)
+            outputs = model(input_ids, attention_mask=attention_mask, labels=labels)
+            loss = outputs[0]
+            loss.backward()
+            optim.step()
+
+    model.eval()
+    ## TENSORFLOW CODE
+    from transformers import TFDistilBertForSequenceClassification
+
+    model = TFDistilBertForSequenceClassification.from_pretrained('distilbert-base-uncased')
+
+    optimizer = tf.keras.optimizers.Adam(learning_rate=5e-5)
+    model.compile(optimizer=optimizer, loss=model.compute_loss) # can also use any keras loss fn
+    model.fit(train_dataset.shuffle(1000).batch(16), epochs=3, batch_size=16)
+
+.. _tok_ner:
+
+Token Classification with W-NUT Emerging Entities
+-------------------------------------------------
+
+.. note::
+
+    This dataset can be explored in the Hugging Face model hub (`WNUT-17 <https://huggingface.co/datasets/wnut_17>`_), and can
+    be alternatively downloaded with the 🤗 NLP library with ``load_dataset("wnut_17")``.
+
+Next we will look at token classification. Rather than classifying an entire sequence, this task classifies token by
+token. We'll demonstrate how to do this with 
+`Named Entity Recognition <http://nlpprogress.com/english/named_entity_recognition.html>`_, which involves
+identifying tokens which correspond to a predefined set of "entities". Specifically, we'll use the
+`W-NUT Emerging and Rare entities <http://noisy-text.github.io/2017/emerging-rare-entities.html>`_ corpus. The data
+is given as a collection of pre-tokenized documents where each token is assigned a tag.
+
+Let's start by downloading the data.
+
+.. code-block:: bash
+
+    wget http://noisy-text.github.io/2017/files/wnut17train.conll
+
+In this case, we'll just download the train set, which is a single text file. Each line of the file contains either
+(1) a word and tag separated by a tab, or (2) a blank line indicating the end of a document. Let's write a
+function to read this in. We'll take in the file path and return ``token_docs`` which is a list of lists of token
+strings, and ``token_tags`` which is a list of lists of tag strings.
+
+.. code-block:: python
+
+    from pathlib import Path
+    import re
+
+    def read_wnut(file_path):
+        file_path = Path(file_path)
+
+        raw_text = file_path.read_text().strip()
+        raw_docs = re.split(r'\n\t?\n', raw_text)
+        token_docs = []
+        tag_docs = []
+        for doc in raw_docs:
+            tokens = []
+            tags = []
+            for line in doc.split('\n'):
+                token, tag = line.split('\t')
+                tokens.append(token)
+                tags.append(tag)
+            token_docs.append(tokens)
+            tag_docs.append(tags)
+        
+        return token_docs, tag_docs
+    
+    texts, tags = read_wnut('wnut17train.conll')
+    
+Just to see what this data looks like, let's take a look at a segment of the first document.
+
+.. code-block:: python
+
+    >>> print(texts[0][10:17], tags[0][10:17], sep='\n')
+    ['for', 'two', 'weeks', '.', 'Empire', 'State', 'Building']
+    ['O', 'O', 'O', 'O', 'B-location', 'I-location', 'I-location']
+
+``location`` is an entity type, ``B-`` indicates the beginning of an entity, and ``I-`` indicates consecutive positions of
+the same entity ("Empire State Building" is considered one entity). ``O`` indicates the token does not correspond to
+any entity.
+
+Now that we've read the data in, let's create a train/validation split:
+
+.. code-block:: python
+
+    from sklearn.model_selection import train_test_split
+    train_texts, val_texts, train_tags, val_tags = train_test_split(texts, tags, test_size=.2)
+
+Next, let's create encodings for our tokens and tags. For the tags, we can start by just create a simple mapping
+which we'll use in a moment:
+
+.. code-block:: python
+
+    unique_tags = set(tag for doc in tags for tag in doc)
+    tag2id = {tag: id for id, tag in enumerate(unique_tags)}
+    id2tag = {id: tag for tag, id in tag2id.items()}
+
+To encode the tokens, we'll use a pre-trained DistilBert tokenizer. We can tell the tokenizer that we're dealing
+with ready-split tokens rather than full sentence strings by passing ``is_pretokenized=True``. We'll also pass
+``padding=True`` and ``truncation=True`` to pad the sequences to be the same length. Lastly, we can tell the model
+to return information about the tokens which are split by the wordpiece tokenization process, which we will need in
+a moment.
+
+.. code-block:: python
+
+    from transformers import DistilBertTokenizerFast
+    tokenizer = DistilBertTokenizerFast.from_pretrained('distilbert-base-cased')
+    train_encodings = tokenizer(train_texts, is_pretokenized=True, return_offsets_mapping=True, padding=True, truncation=True)
+    val_encodings = tokenizer(val_texts, is_pretokenized=True, return_offsets_mapping=True, padding=True, truncation=True)
+
+Great, so now our tokens are nicely encoded in the format that they need to be in to feed them into our DistilBert
+model below.
+
+Now we arrive at a common obstacle with using pre-trained models for token-level classification: many of the tokens
+in the W-NUT corpus are not in DistilBert's vocabulary. Bert and many models like it use a method called WordPiece
+Tokenization, meaning that single words are split into multiple tokens such that each token is likely to be in
+the vocabulary. For example, DistilBert's tokenizer would split the Twitter handle ``@huggingface`` into the tokens
+``['@', 'hugging', '##face']``. This is a problem for us because we have exactly one tag per token. If the tokenizer
+splits a token into multiple sub-tokens, then we will end up with a mismatch between our tokens and our labels.
+
+One way to handle this is to only train on the tag labels for the first subtoken of a split token. We can do this in
+🤗 Transformers by setting the labels we wish to ignore to ``-100``. In the example above, if the label for
+``@HuggingFace`` is ``3`` (indexing ``B-corporation``), we would set the labels of ``['@', 'hugging', '##face']`` to
+``[3, -100, -100]``.
+
+Let's write a function to do this. This is where we will use the ``offset_mapping`` from the tokenizer as mentioned
+above. For each sub-token returned by the tokenizer, the offset mapping gives us a tuple indicating the sub-token's
+start position and end position relative to the original token it was split from. That means that if the first
+position in the tuple is anything other than ``0``, we will set its corresponding label to ``-100``. While we're at
+it, we can also set labels to ``-100`` if the second position of the offset mapping is ``0``, since this means it must
+be a special token like ``[PAD]`` or ``[CLS]``.
+
+.. note:: 
+
+    Due to a recently fixed bug, -1 must be used instead of -100 when using TensorFlow in 🤗 Transformers <= 3.02.
+
+.. code-block:: python
+
+    import numpy as np
+
+    def encode_tags(tags, encodings):
+        labels = [[tag2id[tag] for tag in doc] for doc in tags]
+        encoded_labels = []
+        for doc_labels, doc_offset in zip(labels, encodings.offset_mapping):
+            # create an empty array of -100
+            doc_enc_labels = np.ones(len(doc_offset),dtype=int) * -100
+            arr_offset = np.array(doc_offset)
+
+            # set labels whose first offset position is 0 and the second is not 0
+            doc_enc_labels[(arr_offset[:,0] == 0) & (arr_offset[:,1] != 0)] = doc_labels
+            encoded_labels.append(doc_enc_labels.tolist())
+
+        return encoded_labels
+    
+    train_labels = encode_tags(train_tags, train_encodings)
+    val_labels = encode_tags(val_tags, val_encodings)
+
+The hard part is now done. Just as in the sequence classification example above, we can create a dataset object:
+
+.. code-block:: python
+
+    ## PYTORCH CODE
+    import torch
+
+    class WNUTDataset(torch.utils.data.Dataset):
+        def __init__(self, encodings, labels):
+            self.encodings = encodings
+            self.labels = labels
+
+        def __getitem__(self, idx):
+            item = {key: torch.tensor(val[idx]) for key, val in self.encodings.items()}
+            item['labels'] = torch.tensor(self.labels[idx])
+            return item
+
+        def __len__(self):
+            return len(self.labels)
+
+    train_encodings.pop("offset_mapping") # we don't want to pass this to the model
+    val_encodings.pop("offset_mapping")
+    train_dataset = WNUTDataset(train_encodings, train_labels)
+    val_dataset = WNUTDataset(val_encodings, val_labels)
+    ## TENSORFLOW CODE
+    import tensorflow as tf
+
+    train_encodings.pop("offset_mapping") # we don't want to pass this to the model
+    val_encodings.pop("offset_mapping")
+
+    train_dataset = tf.data.Dataset.from_tensor_slices((
+        dict(train_encodings),
+        train_labels
+    ))
+    val_dataset = tf.data.Dataset.from_tensor_slices((
+        dict(val_encodings),
+        val_labels
+    ))
+
+Now load in a token classification model and specify the number of labels:
+
+.. code-block:: python
+
+    ## PYTORCH CODE
+    from transformers import DistilBertForTokenClassification
+    model = DistilBertForTokenClassification.from_pretrained('distilbert-base-cased', num_labels=len(unique_tags))
+    ## TENSORFLOW CODE
+    from transformers import TFDistilBertForTokenClassification
+    model = TFDistilBertForTokenClassification.from_pretrained('distilbert-base-cased', num_labels=len(unique_tags))
+
+The data and model are both ready to go. You can train the model either with
+:class:`~transformers.Trainer`/:class:`~transformers.TFTrainer` or with native PyTorch/TensorFlow, exactly as in the
+sequence classification example above.
+
+  - :ref:`ft_trainer`
+  - :ref:`ft_native`
+
+.. _qa_squad:
+
+Question Answering with SQuAD 2.0
+---------------------------------
+
+.. note::
+
+    This dataset can be explored in the Hugging Face model hub (`SQuAD V2 <https://huggingface.co/datasets/squad_v2>`_), and can
+    be alternatively downloaded with the 🤗 NLP library with ``load_dataset("squad_v2")``.
+
+Question answering comes in many forms. In this example, we'll look at the particular type of extractive QA that
+involves answering a question about a passage by highlighting the segment of the passage that answers the question.
+This involves fine-tuning a model which predicts a start position and an end position in the passage. We will use the
+`Stanford Question Answering Dataset (SQuAD) 2.0 <https://rajpurkar.github.io/SQuAD-explorer/>`_.
+
+We will start by downloading the data:
+
+.. code-block:: bash
+
+    mkdir squad
+    wget https://rajpurkar.github.io/SQuAD-explorer/dataset/train-v2.0.json -O squad/train-v2.0.json
+    wget https://rajpurkar.github.io/SQuAD-explorer/dataset/dev-v2.0.json -O squad/dev-v2.0.json
+
+Each split is in a structured json file with a number of questions and answers for each passage (or context). We'll
+take this apart into parallel lists of contexts, questions, and answers (note that the contexts here are repeated
+since there are multiple questions per context):
+
+.. code-block:: python
+
+    import json
+    from pathlib import Path
+
+    def read_squad(path):
+        path = Path(path)
+        with open(path, 'rb') as f:
+            squad_dict = json.load(f)
+
+        contexts = []
+        questions = []
+        answers = []
+        for group in squad_dict['data']:
+            for passage in group['paragraphs']:
+                context = passage['context']
+                for qa in passage['qas']:
+                    question = qa['question']
+                    for answer in qa['answers']:
+                        contexts.append(context)
+                        questions.append(question)
+                        answers.append(answer)
+
+        return contexts, questions, answers
+    
+    train_contexts, train_questions, train_answers = read_squad('squad/train-v2.0.json')
+    val_contexts, val_questions, val_answers = read_squad('squad/dev-v2.0.json')
+
+The contexts and questions are just strings. The answers are dicts containing the subsequence of the passage with
+the correct answer as well as an integer indicating the character at which the answer begins. In order to train a
+model on this data we need (1) the tokenized context/question pairs, and (2) integers indicating at which *token*
+positions the answer begins and ends.
+
+First, let's get the *character* position at which the answer ends in the passage (we are given the starting
+position). Sometimes SQuAD answers are off by one or two characters, so we will also adjust for that.
+
+.. code-block:: python
+
+    def add_end_idx(answers, contexts):
+        for answer, context in zip(answers, contexts):
+            gold_text = answer['text']
+            start_idx = answer['answer_start']
+            end_idx = start_idx + len(gold_text)
+            
+            # sometimes squad answers are off by a character or two – fix this
+            if context[start_idx:end_idx] == gold_text:
+                answer['answer_end'] = end_idx
+            elif context[start_idx-1:end_idx-1] == gold_text:
+                answer['answer_start'] = start_idx - 1
+                answer['answer_end'] = end_idx - 1     # When the gold label is off by one character
+            elif context[start_idx-2:end_idx-2] == gold_text:
+                answer['answer_start'] = start_idx - 2
+                answer['answer_end'] = end_idx - 2     # When the gold label is off by two characters
+
+    add_end_idx(train_answers, train_contexts)
+    add_end_idx(val_answers, val_contexts)
+
+Now ``train_answers`` and ``val_answers`` include the character end positions and the corrected start positions.
+Next, let's tokenize our context/question pairs. 🤗 Tokenizers can accept parallel lists of sequences and encode
+them together as sequence pairs.
+
+.. code-block:: python
+
+    from transformers import DistilBertTokenizerFast
+    tokenizer = DistilBertTokenizerFast.from_pretrained('distilbert-base-uncased')
+
+    train_encodings = tokenizer(train_contexts, train_questions, truncation=True, padding=True)
+    val_encodings = tokenizer(val_contexts, val_questions, truncation=True, padding=True)
+
+Next we need to convert our character start/end positions to token start/end positions. When using 🤗 Fast
+Tokenizers, we can use the built in :func:`~transformers.BatchEncoding.char_to_token` method.
+
+.. code-block:: python
+
+    def add_token_positions(encodings, answers):
+        start_positions = []
+        end_positions = []
+        for i in range(len(answers)):
+            start_positions.append(encodings.char_to_token(i, answers[i]['answer_start']))
+            end_positions.append(encodings.char_to_token(i, answers[i]['answer_end'] - 1))
+            # if None, the answer passage has been truncated
+            if start_positions[-1] is None:
+                start_positions[-1] = tokenizer.model_max_length
+            if end_positions[-1] is None:
+                end_positions[-1] = tokenizer.model_max_length
+        encodings.update({'start_positions': start_positions, 'end_positions': end_positions})
+
+    add_token_positions(train_encodings, train_answers)
+    add_token_positions(val_encodings, val_answers)
+
+Our data is ready. Let's just put it in a PyTorch/TensorFlow dataset so that we can easily use it for
+training. In PyTorch, we define a custom ``Dataset`` class. In TensorFlow, we pass a tuple of
+``(inputs_dict, labels_dict)`` to the ``from_tensor_slices`` method.
+
+.. code-block:: python
+
+    ## PYTORCH CODE
+    import torch
+
+    class SquadDataset(torch.utils.data.Dataset):
+        def __init__(self, encodings):
+            self.encodings = encodings
+
+        def __getitem__(self, idx):
+            return {key: torch.tensor(val[idx]) for key, val in self.encodings.items()}
+
+        def __len__(self):
+            return len(self.encodings.input_ids)
+        
+    train_dataset = SquadDataset(train_encodings)
+    val_dataset = SquadDataset(val_encodings)
+    ## TENSORFLOW CODE
+    import tensorflow as tf
+
+    train_dataset = tf.data.Dataset.from_tensor_slices((
+        {key: train_encodings[key] for key in ['input_ids', 'attention_mask']},
+        {key: train_encodings[key] for key in ['start_positions', 'end_positions']}
+    ))
+    val_dataset = tf.data.Dataset.from_tensor_slices((
+        {key: val_encodings[key] for key in ['input_ids', 'attention_mask']},
+        {key: val_encodings[key] for key in ['start_positions', 'end_positions']}
+    ))
+
+Now we can use a DistilBert model with a QA head for training:
+
+.. code-block:: python
+
+    ## PYTORCH CODE
+    from transformers import DistilBertForQuestionAnswering
+    model = DistilBertForQuestionAnswering.from_pretrained("distilbert-base-uncased")
+    ## TENSORFLOW CODE
+    from transformers import TFDistilBertForQuestionAnswering
+    model = TFDistilBertForQuestionAnswering.from_pretrained("distilbert-base-uncased")
+
+
+The data and model are both ready to go. You can train the model with
+:class:`~transformers.Trainer`/:class:`~transformers.TFTrainer` exactly as in the sequence classification example
+above. If using native PyTorch, replace ``labels`` with ``start_positions`` and ``end_positions`` in the training
+example. If using Keras's ``fit``, we need to make a minor modification to handle this example since it involves
+multiple model outputs.
+
+  - :ref:`ft_trainer`
+
+.. code-block:: python
+
+    ## PYTORCH CODE
+    from torch.utils.data import DataLoader
+    from transformers import AdamW
+
+    device = torch.device('cuda') if torch.cuda.is_available() else torch.device('cpu')
+
+    model.to(device)
+    model.train()
+
+    train_loader = DataLoader(train_dataset, batch_size=16, shuffle=True)
+
+    optim = AdamW(model.parameters(), lr=5e-5)
+
+    for epoch in range(3):
+        for batch in train_loader:
+            optim.zero_grad()
+            input_ids = batch['input_ids'].to(device)
+            attention_mask = batch['attention_mask'].to(device)
+            start_positions = batch['start_positions'].to(device)
+            end_positions = batch['end_positions'].to(device)
+            outputs = model(input_ids, attention_mask=attention_mask, start_positions=start_positions, end_positions=end_positions)
+            loss = outputs[0]
+            loss.backward()
+            optim.step()
+
+    model.eval()
+    ## TENSORFLOW CODE
+    # Keras will expect a tuple when dealing with labels
+    train_dataset = train_dataset.map(lambda x, y: (x, (y['start_positions'], y['end_positions'])))
+
+    # Keras will assign a separate loss for each output and add them together. So we'll just use the standard CE loss
+    # instead of using the built-in model.compute_loss, which expects a dict of outputs and averages the two terms.
+    # Note that this means the loss will be 2x of when using TFTrainer since we're adding instead of averaging them.
+    loss = tf.keras.losses.SparseCategoricalCrossentropy(from_logits=True)
+    model.distilbert.return_dict = False # if using 🤗 Transformers >3.02, make sure outputs are tuples
+
+    optimizer = tf.keras.optimizers.Adam(learning_rate=5e-5)
+    model.compile(optimizer=optimizer, loss=loss) # can also use any keras loss fn
+    model.fit(train_dataset.shuffle(1000).batch(16), epochs=3, batch_size=16)
+
+.. _resources:
+
+Additional Resources
+--------------------
+
+  - `How to train a new language model from scratch using Transformers and Tokenizers
+    <https://huggingface.co/blog/how-to-train>`_. Blog post showing the steps to load in Esperanto data and train a
+    masked language model from scratch.
+  - :doc:`Preprocessing <preprocessing>`. Docs page on data preprocessing.
+  - :doc:`Training <training>`. Docs page on training and fine-tuning.
+
+.. _nlplib:
+
+Using the 🤗 NLP Datasets & Metrics library
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This tutorial demonstrates how to read in datasets from various raw text formats and prepare them for training with
+🤗 Transformers so that you can do the same thing with your own custom datasets. However, we recommend users use the
+`🤗 NLP library <https://github.com/huggingface/nlp>`_ for working with the 150+ datasets included in the
+`hub <https://huggingface.co/datasets>`_, including the three datasets used in this tutorial. As a very brief overview,
+we will show how to use the NLP library to download and prepare the IMDb dataset from the first example,
+:ref:`seq_imdb`.
+
+Start by downloading the dataset:
+
+.. code-block:: python
+
+    from nlp import load_dataset
+    train = load_dataset("imdb", split="train")
+
+Each dataset has multiple columns corresponding to different features. Let's see what our columns are.
+
+.. code-block:: python
+
+    >>> print(train.column_names)
+    ['label', 'text']
+
+Great. Now let's tokenize the text. We can do this using the ``map`` method. We'll also rename the ``label`` column
+to ``labels`` to match the model's input arguments.
+
+.. code-block:: python
+
+    train = train.map(lambda batch: tokenizer(batch["text"], truncation=True, padding=True), batched=True)
+    train.rename_column_("label", "labels")
+
+Lastly, we can use the ``set_format`` method to determine which columns and in what data format we want to access
+dataset elements.
+
+.. code-block:: python
+
+    ## PYTORCH CODE
+    >>> train.set_format("torch", columns=["input_ids", "attention_mask", "labels"])
+    >>> {key: val.shape for key, val in train[0].items()})
+    {'labels': torch.Size([]), 'input_ids': torch.Size([512]), 'attention_mask': torch.Size([512])}
+    ## TENSORFLOW CODE
+    >>> train.set_format("tensorflow", columns=["input_ids", "attention_mask", "labels"])
+    >>> {key: val.shape for key, val in train[0].items()})
+    {'labels': TensorShape([]), 'input_ids': TensorShape([512]), 'attention_mask': TensorShape([512])}
+
+We now have a fully-prepared dataset. Check out `the 🤗 NLP docs <https://huggingface.co/nlp/processing.html>`_ for
+a more thorough introduction.

docs/source/glossary.rst

@@ -7,7 +7,7 @@ General terms
 - autoencoding models: see MLM
 - autoregressive models: see CLM
 - CLM: causal language modeling, a pretraining task where the model reads the texts in order and has to predict the
-  next word. It's usually done by reading the whole sentence but using a mask inside the model to hide the future 
+  next word. It's usually done by reading the whole sentence but using a mask inside the model to hide the future
   tokens at a certain timestep.
 - MLM: masked language modeling, a pretraining task where the model sees a corrupted version of the texts, usually done
   by masking some tokens randomly, and has to predict the original text.
@@ -18,7 +18,7 @@ General terms
 - NLU: natural language understanding, all tasks related to understanding what is in a text (for instance classifying
   the whole text, individual words)
 - pretrained model: a model that has been pretrained on some data (for instance all of Wikipedia). Pretraining methods
-  involve a self-supervised objective, which can be reading the text and trying to predict the next word (see CLM) or 
+  involve a self-supervised objective, which can be reading the text and trying to predict the next word (see CLM) or
   masking some words and trying to predict them (see MLM).
 - RNN: recurrent neural network, a type of model that uses a loop over a layer to process texts.
 - seq2seq or sequence-to-sequence: models that generate a new sequence from an input, like translation models, or
@@ -57,7 +57,7 @@ The tokenizer takes care of splitting the sequence into tokens available in the
     >>> tokenized_sequence = tokenizer.tokenize(sequence)
 
 The tokens are either words or subwords. Here for instance, "VRAM" wasn't in the model vocabulary, so it's been split
-in "V", "RA" and "M". To indicate those tokens are not separate words but parts of the same word, a double-dash is
+in "V", "RA" and "M". To indicate those tokens are not separate words but parts of the same word, a double-hash prefix is
 added for "RA" and "M":
 
 ::
@@ -71,24 +71,27 @@ the sentence to the tokenizer, which leverages the Rust implementation of
 
 ::
 
-    >>> encoded_sequence = tokenizer(sequence)["input_ids"]
+    >>> inputs = tokenizer(sequence)
 
 The tokenizer returns a dictionary with all the arguments necessary for its corresponding model to work properly. The
 token indices are under the key "input_ids":
 
 ::
 
+    >>> encoded_sequence = inputs["input_ids"]
     >>> print(encoded_sequence)
     [101, 138, 18696, 155, 1942, 3190, 1144, 1572, 13745, 1104, 159, 9664, 2107, 102]
 
-Note that the tokenizer automatically adds "special tokens" (if the associated model rely on them) which are special
-IDs the model sometimes uses. If we decode the previous sequence of ids,
+Note that the tokenizer automatically adds "special tokens" (if the associated model relies on them) which are special
+IDs the model sometimes uses.
+
+If we decode the previous sequence of ids,
 
 ::
 
     >>> decoded_sequence = tokenizer.decode(encoded_sequence)
 
-we will see 
+we will see
 
 ::
 
@@ -125,7 +128,7 @@ The encoded versions have different lengths:
     >>> len(encoded_sequence_a), len(encoded_sequence_b)
     (8, 19)
 
-Therefore, we can't be put then together in a same tensor as-is. The first sequence needs to be padded up to the length
+Therefore, we can't put them together in the same tensor as-is. The first sequence needs to be padded up to the length
 of the second one, or the second one needs to be truncated down to the length of the first one.
 
 In the first case, the list of IDs will be extended by the padding indices. We can pass a list to the tokenizer and ask
@@ -144,7 +147,7 @@ We can see that 0s have been added on the right of the first sentence to make it
 
 This can then be converted into a tensor in PyTorch or TensorFlow. The attention mask is a binary tensor indicating
 the position of the padded indices so that the model does not attend to them. For the
-:class:`~transformers.BertTokenizer`, :obj:`1` indicate a value that should be attended to while :obj:`0` indicate
+:class:`~transformers.BertTokenizer`, :obj:`1` indicates a value that should be attended to, while :obj:`0` indicates
 a padded value. This attention mask is in the dictionary returned by the tokenizer under the key "attention_mask":
 
 ::
@@ -158,15 +161,15 @@ Token Type IDs
 ~~~~~~~~~~~~~~
 
 Some models' purpose is to do sequence classification or question answering. These require two different sequences to
-be encoded in the same input IDs. They are usually separated by special tokens, such as the classifier and separator
+be joined in a single "input_ids" entry, which usually is performed with the help of special tokens, such as the classifier (``[CLS]``) and separator (``[SEP]``)
 tokens. For example, the BERT model builds its two sequence input as such:
 
 ::
 
    >>> # [CLS] SEQUENCE_A [SEP] SEQUENCE_B [SEP]
 
-We can use our tokenizer to automatically generate such a sentence by passing the two sequences as two arguments (and
-not a list like before) like this:
+We can use our tokenizer to automatically generate such a sentence by passing the two sequences to ``tokenizer`` as two arguments (and
+not a list, like before) like this:
 
 ::
 
@@ -185,31 +188,31 @@ which will return:
     >>> print(decoded)
     [CLS] HuggingFace is based in NYC [SEP] Where is HuggingFace based? [SEP]
 
-This is enough for some models to understand where one sequence ends and where another begins. However, other models
-such as BERT have an additional mechanism, which are the token type IDs (also called segment IDs). They are a binary
-mask identifying the different sequences in the model.
+This is enough for some models to understand where one sequence ends and where another begins. However, other models,
+such as BERT, also deploy token type IDs (also called segment IDs). They are represented as a binary
+mask identifying the two types of sequence in the model.
 
-The tokenizer returns in the dictionary under the key "token_type_ids":
+The tokenizer returns this mask as the "token_type_ids" entry:
 
 ::
 
     >>> encoded_dict['token_type_ids']
     [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1]
 
-The first sequence, the "context" used for the question, has all its tokens represented by :obj:`0`, whereas the
-question has all its tokens represented by :obj:`1`. Some models, like :class:`~transformers.XLNetModel` use an
-additional token represented by a :obj:`2`.
+The first sequence, the "context" used for the question, has all its tokens represented by a :obj:`0`, whereas the
+second sequence, corresponding to the "question", has all its tokens represented by a :obj:`1`.
+
+Some models, like :class:`~transformers.XLNetModel` use an additional token represented by a :obj:`2`.
 
 .. _position-ids:
 
 Position IDs
 ~~~~~~~~~~~~
 
-The position IDs are used by the model to identify which token is at which position. Contrary to RNNs that have the
-position of each token embedded within them, transformers are unaware of the position of each token. The position
-IDs are created for this purpose.
+Contrary to RNNs that have the position of each token embedded within them,
+transformers are unaware of the position of each token. Therefore, the position IDs (``position_ids``) are used by the model to identify each token's position in the list of tokens.
 
-They are an optional parameter. If no position IDs are passed to the model, they are automatically created as absolute
+They are an optional parameter. If no ``position_ids`` is passed to the model, the IDs are automatically created as absolute
 positional embeddings.
 
 Absolute positional embeddings are selected in the range ``[0, config.max_position_embeddings - 1]``. Some models
@@ -220,15 +223,15 @@ use other types of positional embeddings, such as sinusoidal position embeddings
 Feed Forward Chunking
 ~~~~~~~~~~~~~~~~~~~~~
 
-In transformers two feed forward layers usually follows the self attention layer in each residual attention block.
+In each residual attention block in transformers the self-attention layer is usually followed by 2 feed forward layers.
 The intermediate embedding size of the feed forward layers is often bigger than the hidden size of the model (e.g.,
-for ``bert-base-uncased``). 
+for ``bert-base-uncased``).
 
 For an input of size ``[batch_size, sequence_length]``, the memory required to store the intermediate feed forward
 embeddings ``[batch_size, sequence_length, config.intermediate_size]`` can account for a large fraction of the memory
 use. The authors of `Reformer: The Efficient Transformer <https://arxiv.org/abs/2001.04451>`_ noticed that since the
 computation is independent of the ``sequence_length`` dimension, it is mathematically equivalent to compute the output
-embeddings of both feed forward layers ``[batch_size, config.hidden_size]_0, ..., [batch_size, config.hidden_size]_n`` 
+embeddings of both feed forward layers ``[batch_size, config.hidden_size]_0, ..., [batch_size, config.hidden_size]_n``
 individually and concat them afterward to ``[batch_size, sequence_length, config.hidden_size]`` with
 ``n = sequence_length``, which trades increased computation time against reduced memory use, but yields a
 mathematically **equivalent** result.

docs/source/index.rst

@@ -126,14 +126,21 @@ conversion utilities for the following models:
     Min, Patrick Lewis, Ledell Wu, Sergey Edunov, Danqi Chen, and Wen-tau Yih.
 23. `Pegasus <https://github.com/google-research/pegasus>`_ (from Google) released with the paper `PEGASUS: Pre-training with Extracted Gap-sentences for Abstractive Summarization
     <https://arxiv.org/abs/1912.08777>`_ by Jingqing Zhang, Yao Zhao, Mohammad Saleh and Peter J. Liu.
-24. `MBart <https://github.com/pytorch/fairseq/tree/master/examples/mbart>`_ (from Facebook) released with the paper  `Multilingual Denoising Pre-training for Neural Machine
-    Translation <https://arxiv.org/abs/2001.08210>`_ by Yinhan Liu, Jiatao Gu, Naman Goyal, Xian Li, Sergey Edunov
+24. `MBart <https://github.com/pytorch/fairseq/tree/master/examples/mbart>`_ (from Facebook) released with the paper  `Multilingual Denoising Pre-training for Neural Machine Translation <https://arxiv.org/abs/2001.08210>`_ by Yinhan Liu, Jiatao Gu, Naman Goyal, Xian Li, Sergey Edunov,
     Marjan Ghazvininejad, Mike Lewis, Luke Zettlemoyer.
-25. `Other community models <https://huggingface.co/models>`_, contributed by the `community
-    <https://huggingface.co/users>`_.
-26. `Blenderbot <https://github.com/facebookresearch/ParlAI>`_ (from Facebook AI Research) released with the paper `Recipes for building an open-domain chatbot
+25. `LXMERT <https://github.com/airsplay/lxmert>`_ (from UNC Chapel Hill) released with the paper `LXMERT: Learning
+    Cross-Modality Encoder Representations from Transformers for Open-Domain Question
+    Answering <https://arxiv.org/abs/1908.07490>`_ by Hao Tan and Mohit Bansal.
+26. `Funnel Transformer <https://github.com/laiguokun/Funnel-Transformer>`_ (from CMU/Google Brain) released with the paper
+    `Funnel-Transformer: Filtering out Sequential Redundancy for Efficient Language Processing
+    <https://arxiv.org/abs/2006.03236>`_ by Zihang Dai, Guokun Lai, Yiming Yang, Quoc V. Le.
+27. `Bert For Sequence Generation <https://tfhub.dev/s?module-type=text-generation&subtype=module,placeholder>`_ (from Google) released with the paper
+    `Leveraging Pre-trained Checkpoints for Sequence Generation Tasks
+    <https://arxiv.org/abs/1907.12461>`_ by Sascha Rothe, Shashi Narayan, Aliaksei Severyn.
+28. `Blenderbot <https://github.com/facebookresearch/ParlAI>`_ (from Facebook AI Research) released with the paper `Recipes for building an open-domain chatbot
     <https://arxiv.org/abs/2004.13637>`_ by Stephen Roller, Emily Dinan, Naman Goyal, Da Ju, Mary Williamson, Yinhan Liu, Jing Xu, Myle Ott, Kurt Shuster, Eric M. Smith, Y-Lan Boureau, Jason Weston
-
+29. `Other community models <https://huggingface.co/models>`_, contributed by the `community
+    <https://huggingface.co/users>`_.
 .. toctree::
     :maxdepth: 2
     :caption: Get started
@@ -161,10 +168,12 @@ conversion utilities for the following models:
 
     pretrained_models
     examples
+    custom_datasets
     notebooks
     converting_tensorflow_models
     migration
     contributing
+    testing
     serialization
 
 .. toctree::
@@ -187,6 +196,7 @@ conversion utilities for the following models:
     main_classes/trainer
     main_classes/optimizer_schedules
     main_classes/processors
+    main_classes/logging
     model_doc/auto
     model_doc/encoderdecoder
     model_doc/bert
@@ -215,6 +225,9 @@ conversion utilities for the following models:
     model_doc/pegasus
     model_doc/blenderbot
     model_doc/mbart
+    model_doc/funnel
+    model_doc/lxmert
+    model_doc/bertgeneration
     internal/modeling_utils
     internal/tokenization_utils
     internal/pipelines_utils

docs/source/installation.md

@@ -22,13 +22,13 @@ When TensorFlow 2.0 and/or PyTorch has been installed, 🤗 Transformers can be
 pip install transformers
 ```
 
-Alternatively, for CPU-support only, you can install 🤗 Transformers and PyTorch in one line with
+Alternatively, for CPU-support only, you can install 🤗 Transformers and PyTorch in one line with:
 
 ```bash
 pip install transformers[torch]
 ```
 
-or 🤗 Transformers and TensorFlow 2.0 in one line with
+or 🤗 Transformers and TensorFlow 2.0 in one line with:
 
 ```bash
 pip install transformers[tf-cpu]
@@ -73,8 +73,8 @@ This library provides pretrained models that will be downloaded and cached local
 folder given by the shell environment variable ``TRANSFORMERS_CACHE``. The default value for it will be the PyTorch
 cache home followed by ``/transformers/`` (even if you don't have PyTorch installed). This is (by order of priority):
 
-  * shell environment variable ``ENV_TORCH_HOME``
-  * shell environment variable ``ENV_XDG_CACHE_HOME`` + ``/torch/``
+  * shell environment variable ``TORCH_HOME``
+  * shell environment variable ``XDG_CACHE_HOME`` + ``/torch/``
   * default: ``~/.cache/torch/``
 
 So if you don't have any specific environment variable set, the cache directory will be at

docs/source/main_classes/configuration.rst

@@ -1,12 +1,13 @@
 Configuration
 ----------------------------------------------------
 
-The base class ``PretrainedConfig`` implements the common methods for loading/saving a configuration either from a
-local file or directory, or from a pretrained model configuration provided by the library (downloaded from
-HuggingFace's AWS S3 repository).
+The base class :class:`~transformers.PretrainedConfig` implements the common methods for loading/saving a configuration
+either from a local file or directory, or from a pretrained model configuration provided by the library (downloaded
+from HuggingFace's AWS S3 repository).
 
-``PretrainedConfig``
-~~~~~~~~~~~~~~~~~~~~~
+
+PretrainedConfig
+~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.PretrainedConfig
     :members:

docs/source/main_classes/logging.rst

@@ -0,0 +1,52 @@
+Logging
+-------
+
+🤗 Transformers has a centralized logging system, so that you can setup the verbosity of the library easily.
+
+Currently the default verbosity of the library is ``WARNING``.
+
+To change the level of verbosity, just use one of the direct setters. For instance, here is how to change the verbosity to the INFO level.
+
+.. code-block:: python
+
+    import transformers
+    transformers.logging.set_verbosity_info()
+
+You can also use the environment variable ``TRANSFORMERS_VERBOSITY`` to override the default verbosity. You can set it to one of the following: ``debug``, ``info``, ``warning``, ``error``, ``critical``. For example:
+
+.. code-block:: bash
+               
+    TRANSFORMERS_VERBOSITY=error ./myprogram.py
+
+All the methods of this logging module are documented below, the main ones are
+:func:`transformers.logging.get_verbosity` to get the current level of verbosity in the logger and
+:func:`transformers.logging.set_verbosity` to set the verbosity to the level of your choice. In order (from the least
+verbose to the most verbose), those levels (with their corresponding int values in parenthesis) are:
+
+- :obj:`transformers.logging.CRITICAL` or :obj:`transformers.logging.FATAL` (int value, 50): only report the most
+  critical errors.
+- :obj:`transformers.logging.ERROR` (int value, 40): only report errors.
+- :obj:`transformers.logging.WARNING` or :obj:`transformers.logging.WARN` (int value, 30): only reports error and
+  warnings. This the default level used by the library.
+- :obj:`transformers.logging.INFO` (int value, 20): reports error, warnings and basic information.
+- :obj:`transformers.logging.DEBUG` (int value, 10): report all information.
+
+Base setters
+~~~~~~~~~~~~
+
+.. autofunction:: transformers.logging.set_verbosity_error
+
+.. autofunction:: transformers.logging.set_verbosity_warning
+
+.. autofunction:: transformers.logging.set_verbosity_info
+
+.. autofunction:: transformers.logging.set_verbosity_debug
+
+Other functions
+~~~~~~~~~~~~~~~
+
+.. autofunction:: transformers.logging.get_verbosity
+
+.. autofunction:: transformers.logging.set_verbosity
+
+.. autofunction:: transformers.logging.get_logger

docs/source/main_classes/model.rst

@@ -12,7 +12,9 @@ are common among all the models to:
 - prune the attention heads of the model.
 
 The other methods that are common to each model are defined in :class:`~transformers.modeling_utils.ModuleUtilsMixin`
-(for the PyTorch models) and :class:`~transformers.modeling_tf_utils.TFModuleUtilsMixin` (for the TensorFlow models).
+(for the PyTorch models) and :class:`~transformers.modeling_tf_utils.TFModuleUtilsMixin` (for the TensorFlow models) or
+for text generation, :class:`~transformers.generation_utils.GenerationMixin` (for the PyTorch models) and
+:class:`~transformers.generation_tf_utils.TFGenerationMixin` (for the TensorFlow models)
 
 
 ``PreTrainedModel``
@@ -46,4 +48,8 @@ The other methods that are common to each model are defined in :class:`~transfor
 Generative models
 ~~~~~~~~~~~~~~~~~
 
-Coming soon
+.. autoclass:: transformers.generation_utils.GenerationMixin
+    :members:
+
+.. autoclass:: transformers.generation_tf_utils.TFGenerationMixin
+    :members:

docs/source/main_classes/optimizer_schedules.rst

@@ -13,6 +13,11 @@ The ``.optimization`` module provides:
 .. autoclass:: transformers.AdamW
     :members:
 
+``AdaFactor`` (PyTorch)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.Adafactor
+
 ``AdamWeightDecay`` (TensorFlow)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

docs/source/main_classes/pipelines.rst

@@ -21,6 +21,7 @@ There are two categories of pipeline abstractions to be aware about:
     - :class:`~transformers.TokenClassificationPipeline`
     - :class:`~transformers.TranslationPipeline`
     - :class:`~transformers.ZeroShotClassificationPipeline`
+    - :class:`~transformers.Text2TextGenerationPipeline`
 
 The pipeline abstraction
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -91,6 +92,13 @@ TextGenerationPipeline
     :special-members: __call__
     :members:
 
+Text2TextGenerationPipeline
+==========================================
+
+.. autoclass:: transformers.Text2TextGenerationPipeline
+    :special-members: __call__
+    :members:
+
 TokenClassificationPipeline
 ==========================================
 
@@ -105,7 +113,6 @@ ZeroShotClassificationPipeline
     :special-members: __call__
     :members:
 
-
 Parent class: :obj:`Pipeline`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

docs/source/main_classes/trainer.rst

@@ -21,12 +21,25 @@ previous features. To inject custom behavior you can subclass them and override
 - **setup_wandb** -- Setups wandb (see `here <https://docs.wandb.com/huggingface>`__ for more information).
 - **create_optimizer_and_scheduler** -- Setups the optimizer and learning rate scheduler if they were not passed at
   init.
+- **compute_loss** - Computes the loss on a batch of training inputs.
 - **training_step** -- Performs a training step.
 - **prediction_step** -- Performs an evaluation/test step.
 - **run_model** (TensorFlow only) -- Basic pass through the model.
 - **evaluate** -- Runs an evaluation loop and returns metrics.
 - **predict** -- Returns predictions (with metrics if labels are available) on a test set.
 
+Here is an example of how to customize :class:`~transformers.Trainer` using a custom loss function:
+
+.. code-block:: python
+
+    from transformers import Trainer
+    class MyTrainer(Trainer):
+        def compute_loss(self, model, inputs):
+            labels = inputs.pop("labels")
+            outputs = models(**inputs)
+            logits = outputs[0]
+            return my_custom_loss(logits, labels)
+
 
 ``Trainer`` 
 ~~~~~~~~~~~

docs/source/model_doc/auto.rst

@@ -1,109 +1,131 @@
-AutoModels
+AutoClasses
 -----------
 
 In many cases, the architecture you want to use can be guessed from the name or the path of the pretrained model you
-are supplying to the ``from_pretrained`` method.
-
+are supplying to the :obj:`from_pretrained()` method.
 AutoClasses are here to do this job for you so that you automatically retrieve the relevant model given the name/path
-to the pretrained weights/config/vocabulary:
+to the pretrained weights/config/vocabulary.
 
-Instantiating one of ``AutoModel``, ``AutoConfig`` and ``AutoTokenizer`` will directly create a class of the relevant
-architecture (ex: ``model = AutoModel.from_pretrained('bert-base-cased')`` will create a instance of 
-:class:`~transformers.BertModel`).
+Instantiating one of :class:`~transformers.AutoConfig`, :class:`~transformers.AutoModel`, and
+:class:`~transformers.AutoTokenizer` will directly create a class of the relevant architecture. For instance
 
 
-``AutoConfig``
-~~~~~~~~~~~~~~~~~~~~~
+.. code-block:: python
+
+    model = AutoModel.from_pretrained('bert-base-cased')
+
+will create a model that is an instance of :class:`~transformers.BertModel`.
+
+There is one class of :obj:`AutoModel` for each task, and for each backend (PyTorch or TensorFlow).
+
+
+AutoConfig
+~~~~~~~~~~
 
 .. autoclass:: transformers.AutoConfig
     :members:
 
 
-``AutoTokenizer``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+AutoTokenizer
+~~~~~~~~~~~~~
 
 .. autoclass:: transformers.AutoTokenizer
     :members:
 
 
-``AutoModel``
-~~~~~~~~~~~~~~~~~~~~~
+AutoModel
+~~~~~~~~~
 
 .. autoclass:: transformers.AutoModel
     :members:
 
 
-``AutoModelForPreTraining``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+AutoModelForPreTraining
+~~~~~~~~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.AutoModelForPreTraining
     :members:
 
 
-``AutoModelWithLMHead``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+AutoModelWithLMHead
+~~~~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.AutoModelWithLMHead
     :members:
 
 
-``AutoModelForSequenceClassification``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+AutoModelForSequenceClassification
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.AutoModelForSequenceClassification
     :members:
 
 
-``AutoModelForQuestionAnswering``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+AutoModelForMultipleChoice
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.AutoModelForMultipleChoice
+    :members:
+
+
+AutoModelForTokenClassification
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.AutoModelForTokenClassification
+    :members:
+
+
+AutoModelForQuestionAnswering
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.AutoModelForQuestionAnswering
     :members:
 
 
-``AutoModelForTokenClassification``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-.. autoclass:: transformers.AutoModelForTokenClassification
-    :members:
-
-``TFAutoModel``
-~~~~~~~~~~~~~~~~~~~~~
+TFAutoModel
+~~~~~~~~~~~
 
 .. autoclass:: transformers.TFAutoModel
     :members:
 
 
-``TFAutoModelForPreTraining``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+TFAutoModelForPreTraining
+~~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.TFAutoModelForPreTraining
     :members:
 
 
-``TFAutoModelWithLMHead``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+TFAutoModelWithLMHead
+~~~~~~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.TFAutoModelWithLMHead
     :members:
 
 
-``TFAutoModelForSequenceClassification``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+TFAutoModelForSequenceClassification
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.TFAutoModelForSequenceClassification
     :members:
 
 
-``TFAutoModelForQuestionAnswering``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+TFAutoModelForMultipleChoice
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: transformers.TFAutoModelForQuestionAnswering
+.. autoclass:: transformers.TFAutoModelForMultipleChoice
     :members:
 
 
-``TFAutoModelForTokenClassification``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+TFAutoModelForTokenClassification
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.TFAutoModelForTokenClassification
     :members:
+
+
+TFAutoModelForQuestionAnswering
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFAutoModelForQuestionAnswering
+    :members:

docs/source/model_doc/bart.rst

@@ -32,7 +32,7 @@ BartForConditionalGeneration
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.BartForConditionalGeneration
-    :members: generate, forward
+    :members: forward
 
 
 BartConfig

docs/source/model_doc/bertgeneration.rst

@@ -0,0 +1,82 @@
+BertGeneration
+----------------------------------------------------
+
+Overview
+~~~~~~~~~~~~~~~~~~~~~
+
+The BertGeneration model is a BERT model that can be leveraged for sequence-to-sequence tasks using :class:`~transformers.EncoderDecoderModel` as proposed in `Leveraging Pre-trained Checkpoints for Sequence Generation Tasks <https://arxiv.org/abs/1907.12461>`__ by Sascha Rothe, Shashi Narayan, Aliaksei Severyn.
+
+The abstract from the paper is the following:
+
+*Unsupervised pre-training of large neural models has recently revolutionized Natural Language Processing. By warm-starting from the publicly released checkpoints, NLP practitioners have pushed the state-of-the-art on multiple benchmarks while saving significant amounts of compute time. So far the focus has been mainly on the Natural Language Understanding tasks. In this paper, we demonstrate the efficacy of pre-trained checkpoints for Sequence Generation. We developed a Transformer-based sequence-to-sequence model that is compatible with publicly available pre-trained BERT, GPT-2 and RoBERTa checkpoints and conducted an extensive empirical study on the utility of initializing our model, both encoder and decoder, with these checkpoints. Our models result in new state-of-the-art results on Machine Translation, Text Summarization, Sentence Splitting, and Sentence Fusion.*
+
+Usage:
+
+- The model can be used in combination with the :class:`~transformers.EncoderDecoderModel` to leverage two bert pretrained bert checkpoints for subsequent fine-tuning.
+
+::
+  
+  # leverage checkpoints for Bert2Bert model...
+  encoder = BertGenerationEncoder.from_pretrained("bert-large-uncased", bos_token_id=101, eos_token_id=102)  # use BERT's cls token as BOS token and sep token as EOS token
+  decoder = BertGenerationDecoder.from_pretrained("bert-large-uncased", add_cross_attention=True, is_decoder=True, bos_token_id=101, eos_token_id=102)  # add cross attention layers and use BERT's cls token as BOS token and sep token as EOS token
+  bert2bert = EncoderDecoderModel(encoder=encoder, decoder=decoder)
+  
+  # create tokenizer...
+  tokenizer = BertTokenizer.from_pretrained("bert-large-uncased")
+
+  input_ids = tokenizer('This is a long article to summarize', add_special_tokens=False, return_tensors="pt").input_ids
+  labels = tokenizer('This is a short summary', return_tensors="pt").input_ids
+
+  # train...
+  loss = bert2bert(input_ids=input_ids, decoder_input_ids=labels, labels=labels, return_dict=True).loss
+  loss.backward()
+
+
+- Pretrained :class:`~transformers.EncoderDecoderModel` are also directly available in the model hub, *e.g.*:
+
+
+::
+
+  # instantiate sentence fusion model
+  sentence_fuser = EncoderDecoderModel.from_pretrained("google/roberta2roberta_L-24_discofuse")
+  tokenizer = AutoTokenizer.from_pretrained("google/roberta2roberta_L-24_discofuse")
+
+  input_ids = tokenizer('This is the first sentence. This is the second sentence.', add_special_tokens=False, return_tensors="pt").input_ids
+
+  outputs = sentence_fuser.generate(input_ids)
+
+  print(tokenizer.decode(outputs[0]))
+
+
+Tips:
+
+- :class:`~transformers.BertGenerationEncoder` and :class:`~transformers.BertGenerationDecoder`  should be used in combination with :class:`~transformers.EncoderDecoder`.
+- For summarization, sentence splitting, sentence fusion and translation, no special tokens are required for the input. Therefore, no EOS token should be added to the end of the input.
+
+The original code can be found `here <https://tfhub.dev/s?module-type=text-generation&subtype=module,placeholder>`__.
+
+BertGenerationConfig
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.BertGenerationConfig
+    :members:
+
+
+BertGenerationTokenizer
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.BertGenerationTokenizer
+    :members: 
+
+BertGenerationEncoder
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.BertGenerationEncoder
+    :members:
+
+
+BertGenerationDecoder
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.BertGenerationDecoder
+    :members:

docs/source/model_doc/camembert.rst

@@ -49,6 +49,13 @@ CamembertModel
     :members:
 
 
+CamembertForCausalLM
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.CamembertForCausalLM
+    :members:
+
+
 CamembertForMaskedLM
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

docs/source/model_doc/encoderdecoder.rst

@@ -1,12 +1,13 @@
 Encoder Decoder Models
 ------------------------
 
-This class can wrap an encoder model, such as ``BertModel`` and a decoder modeling with a language modeling head, such as ``BertForMaskedLM`` into a encoder-decoder model.
+The :class:`~transformers.EncoderDecoderModel` can be used to initialize a sequence-to-sequence model with any pre-trained autoencoding model as the encoder and any pre-trained autoregressive model as the decoder.
 
-The ``EncoderDecoderModel`` class allows to instantiate a encoder decoder model using the ``from_encoder_decoder_pretrain`` class method taking a pretrained encoder and pretrained decoder model as an input. 
-The ``EncoderDecoderModel`` is saved using the standard ``save_pretrained()`` method and can also again be loaded using the standard ``from_pretrained()`` method. 
+The effectiveness of initializing sequence-to-sequence models with pre-trained checkpoints for sequence generation tasks was shown in `Leveraging Pre-trained Checkpoints for Sequence Generation Tasks <https://arxiv.org/abs/1907.12461>`__ by Sascha Rothe, Shashi Narayan, Aliaksei Severyn.
 
-An application of this architecture could be *summarization* using two pretrained Bert models as is shown in the paper: `Text Summarization with Pretrained Encoders <https://arxiv.org/abs/1910.13461>`_ by Yang Liu and Mirella Lapata. 
+After such an :class:`~transformers.EncoderDecoderModel` has been trained / fine-tuned, it can be saved / loaded just like any other models (see Examples for more information).
+
+An application of this architecture could be to leverage two pre-trained :obj:`transformers.BertModel` models as the encoder and decoder for a summarization model as was shown in: `Text Summarization with Pretrained Encoders <https://arxiv.org/abs/1908.08345>`_ by Yang Liu and Mirella Lapata. 
 
 
 ``EncoderDecoderConfig``

docs/source/model_doc/funnel.rst

@@ -0,0 +1,185 @@
+Funnel Transformer
+------------------
+
+Overview
+~~~~~~~~~~~~~~~~~~~~~
+
+The Funnel Transformer model was proposed in the paper
+`Funnel-Transformer: Filtering out Sequential Redundancy for Efficient Language Processing
+<https://arxiv.org/abs/2006.03236>`__.
+It is a bidirectional transformer model, like BERT, but with a pooling operation after each block of layers, a bit
+like in traditional convolutional neural networks (CNN) in computer vision.
+
+The abstract from the paper is the following:
+
+*With the success of language pretraining, it is highly desirable to develop more efficient architectures of good
+scalability that can exploit the abundant unlabeled data at a lower cost. To improve the efficiency, we examine the
+much-overlooked redundancy in maintaining a full-length token-level presentation, especially for tasks that only
+require a single-vector presentation of the sequence. With this intuition, we propose Funnel-Transformer which
+gradually compresses the sequence of hidden states to a shorter one and hence reduces the computation cost. More
+importantly, by re-investing the saved FLOPs from length reduction in constructing a deeper or wider model, we further
+improve the model capacity. In addition, to perform token-level predictions as required by common pretraining
+objectives, Funnel-Transformer is able to recover a deep representation for each token from the reduced hidden sequence
+via a decoder. Empirically, with comparable or fewer FLOPs, Funnel-Transformer outperforms the standard Transformer on
+a wide variety of sequence-level prediction tasks, including text classification, language understanding, and reading
+comprehension.*
+
+Tips:
+
+- Since Funnel Transformer uses pooling, the sequence length of the hidden states changes after each block of layers.
+  The base model therefore has a final sequence length that is a quarter of the original one. This model can be used
+  directly for tasks that just require a sentence summary (like sequence classification or multiple choice). For other
+  tasks, the full model is used; this full model has a decoder that upsamples the final hidden states to the same
+  sequence length as the input.
+- The Funnel Transformer checkpoints are all available with a full version and a base version. The first ones should
+  be used for :class:`~transformers.FunnelModel`, :class:`~transformers.FunnelForPreTraining`,
+  :class:`~transformers.FunnelForMaskedLM`, :class:`~transformers.FunnelForTokenClassification` and
+  class:`~transformers.FunnelForQuestionAnswering`. The second ones should be used for
+  :class:`~transformers.FunnelBaseModel`, :class:`~transformers.FunnelForSequenceClassification` and
+  :class:`~transformers.FunnelForMultipleChoice`.
+
+The original code can be found `here <https://github.com/laiguokun/Funnel-Transformer>`_.
+
+
+FunnelConfig
+~~~~~~~~~~~~
+
+.. autoclass:: transformers.FunnelConfig
+    :members:
+
+
+FunnelTokenizer
+~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FunnelTokenizer
+    :members: build_inputs_with_special_tokens, get_special_tokens_mask,
+        create_token_type_ids_from_sequences, save_vocabulary
+
+
+FunnelTokenizerFast
+~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FunnelTokenizerFast
+    :members:
+
+
+Funnel specific outputs
+~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.modeling_funnel.FunnelForPreTrainingOutput
+    :members:
+
+.. autoclass:: transformers.modeling_tf_funnel.TFFunnelForPreTrainingOutput
+    :members:
+
+
+FunnelBaseModel
+~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FunnelBaseModel
+    :members:
+
+
+FunnelModel
+~~~~~~~~~~~
+
+.. autoclass:: transformers.FunnelModel
+    :members:
+
+
+FunnelModelForPreTraining
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FunnelForPreTraining
+    :members:
+
+
+FunnelForMaskedLM
+~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FunnelForMaskedLM
+    :members:
+
+
+FunnelForSequenceClassification
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FunnelForSequenceClassification
+    :members:
+
+
+FunnelForMultipleChoice
+~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FunnelForMultipleChoice
+    :members:
+
+
+FunnelForTokenClassification
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FunnelForTokenClassification
+    :members:
+
+
+FunnelForQuestionAnswering
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.FunnelForQuestionAnswering
+    :members:
+
+
+TFFunnelBaseModel
+~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFFunnelBaseModel
+    :members:
+
+
+TFFunnelModel
+~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFFunnelModel
+    :members:
+
+
+TFFunnelModelForPreTraining
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFFunnelForPreTraining
+    :members:
+
+
+TFFunnelForMaskedLM
+~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFFunnelForMaskedLM
+    :members:
+
+
+TFFunnelForSequenceClassification
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFFunnelForSequenceClassification
+    :members:
+
+
+TFFunnelForMultipleChoice
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFFunnelForMultipleChoice
+    :members:
+
+
+TFFunnelForTokenClassification
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFFunnelForTokenClassification
+    :members:
+
+
+TFFunnelForQuestionAnswering
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFFunnelForQuestionAnswering
+    :members:

docs/source/model_doc/lxmert.rst

@@ -0,0 +1,109 @@
+LXMERT
+----------------------------------------------------
+
+Overview
+~~~~~~~~~~~~~~~~~~~~~
+
+The LXMERT model was proposed in `LXMERT: Learning Cross-Modality Encoder Representations from Transformers <https://arxiv.org/abs/1908.07490>`__
+by Hao Tan & Mohit Bansal. It is a series of bidirectional transformer encoders (one for the vision modality, one for the language modality, and then one to fuse both modalities)
+pre-trained using a combination of masked language modeling, visual-language text alignment, ROI-feature regression, masked visual-attribute modeling, masked visual-object modeling, and visual-question answering objectives.
+The pretraining consists of multiple multi-modal datasets: MSCOCO, Visual-Genome + Visual-Genome Question Answering, VQA 2.0, and GQA.
+
+The abstract from the paper is the following:
+
+*Vision-and-language reasoning requires an understanding of visual concepts, language semantics, and, most importantly, the alignment and relationships between these two
+modalities. We thus propose the LXMERT
+(Learning Cross-Modality Encoder Representations from Transformers) framework to learn
+these vision-and-language connections. In
+LXMERT, we build a large-scale Transformer
+model that consists of three encoders: an object relationship encoder, a language encoder,
+and a cross-modality encoder. Next, to endow our model with the capability of connecting vision and language semantics, we
+pre-train the model with large amounts of
+image-and-sentence pairs, via five diverse representative pre-training tasks: masked language modeling, masked object prediction
+(feature regression and label classification),
+cross-modality matching, and image question answering. These tasks help in learning both intra-modality and cross-modality relationships. After fine-tuning from our pretrained parameters, our model achieves the
+state-of-the-art results on two visual question answering datasets (i.e., VQA and GQA).
+We also show the generalizability of our pretrained cross-modality model by adapting it to
+a challenging visual-reasoning task, NLVR
+,
+and improve the previous best result by 22%
+absolute (54% to 76%). Lastly, we demonstrate detailed ablation studies to prove that
+both our novel model components and pretraining strategies significantly contribute to
+our strong results; and also present several
+attention visualizations for the different encoders*
+
+Tips:
+
+- Bounding boxes are not necessary to be used in the visual feature embeddings, any kind of visual-spacial features will work.
+- Both the language hidden states and the visual hidden states that LXMERT outputs are passed through the cross-modality layer, so they
+  contain information from both modalities. To access a modality that only attends to itself, select the vision/language hidden states from the first input in the tuple.
+- The bi-directional cross-modality encoder attention only returns attention values when the language modality is used as the input and the vision modality is used as the context vector. Further,
+  while the cross-modality encoder contains self-attention for each respective modality and cross-attention, only the cross attention is returned and both self attention outputs are disregarded.
+
+The code can be found `here <https://github.com/airsplay/lxmert>`__
+
+
+LxmertConfig
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.LxmertConfig
+    :members:
+
+
+LxmertTokenizer
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.LxmertTokenizer
+    :members: build_inputs_with_special_tokens, get_special_tokens_mask,
+        create_token_type_ids_from_sequences, save_vocabulary
+
+
+Lxmert specific outputs
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.modeling_lxmert.LxmertModelOutput
+    :members:
+
+.. autoclass:: transformers.modeling_lxmert.LxmertForPreTrainingOutput
+    :members:
+
+.. autoclass:: transformers.modeling_lxmert.LxmertForQuestionAnsweringOutput
+    :members:
+
+.. autoclass:: transformers.modeling_tf_lxmert.TFLxmertModelOutput
+    :members:
+
+.. autoclass:: transformers.modeling_tf_lxmert.TFLxmertForPreTrainingOutput
+    :members:
+
+
+LxmertModel
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.LxmertModel
+    :members:
+
+LxmertForPreTraining
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.LxmertForPreTraining
+    :members:
+
+LxmertForQuestionAnswering
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.LxmertForQuestionAnswering
+    :members:
+
+
+TFLxmertModel
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFLxmertModel
+    :members:
+
+TFLxmertForPreTraining
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFLxmertForPreTraining
+    :members:

docs/source/model_doc/marian.rst

@@ -1,14 +1,14 @@
 MarianMT
 ----------------------------------------------------
-**DISCLAIMER:** If you see something strange,
-file a `Github Issue <https://github.com/huggingface/transformers/issues/new?assignees=&labels=&template=bug-report.md&title>`__ and assign
+**Bugs:** If you see something strange,
+file a `Github Issue <https://github.com/huggingface/transformers/issues/new?assignees=sshleifer&labels=&template=bug-report.md&title>`__ and assign
 @sshleifer. Translations should be similar, but not identical to, output in the test set linked to in each model card.
 
 Implementation Notes
 ~~~~~~~~~~~~~~~~~~~~
 - Each model is about 298 MB on disk, there are 1,000+ models.
 - The list of supported language pairs can be found `here <https://huggingface.co/Helsinki-NLP>`__.
-- The 1,000+ models were originally trained by `Jörg Tiedemann <https://researchportal.helsinki.fi/en/persons/j%C3%B6rg-tiedemann>`__ using the `Marian <https://marian-nmt.github.io/>`_ C++ library, which supports fast training and translation.
+- models were originally trained by `Jörg Tiedemann <https://researchportal.helsinki.fi/en/persons/j%C3%B6rg-tiedemann>`__ using the `Marian <https://marian-nmt.github.io/>`_ C++ library, which supports fast training and translation.
 - All models are transformer encoder-decoders with 6 layers in each component. Each model's performance is documented in a model card.
 - The 80 opus models that require BPE preprocessing are not supported.
 - The modeling code is the same as ``BartForConditionalGeneration`` with a few minor modifications:

docs/source/model_doc/mbart.rst

@@ -14,6 +14,45 @@ MBART is a sequence-to-sequence denoising auto-encoder pre-trained on large-scal
 The Authors' code can be found `here <https://github.com/pytorch/fairseq/tree/master/examples/mbart>`__
 
 
+Training
+~~~~~~~~~~~~~~~~~~~~~
+MBart is a multilingual encoder-decoder (seq-to-seq) model primarily intended for translation task. 
+As the model is multilingual it expects the sequences in a different format. A special language id token 
+is added in both the source and target text. The source text format is ``X [eos, src_lang_code]`` 
+where ``X`` is the source text. The target text format is ```[tgt_lang_code] X [eos]```. ```bos``` is never used.
+The ```MBartTokenizer.prepare_seq2seq_batch``` handles this automatically and should be used to encode 
+the sequences for seq-2-seq fine-tuning.
+
+- Supervised training
+
+::
+
+    example_english_phrase = "UN Chief Says There Is No Military Solution in Syria"
+    expected_translation_romanian = "Şeful ONU declară că nu există o soluţie militară în Siria"
+    batch = tokenizer.prepare_seq2seq_batch(example_english_phrase, src_lang="en_XX", tgt_lang="ro_RO", tgt_texts=expected_translation_romanian)
+    input_ids = batch["input_ids"]
+    target_ids = batch["decoder_input_ids"]
+    decoder_input_ids = target_ids[:, :-1].contiguous()
+    labels = target_ids[:, 1:].clone()
+    model(input_ids=input_ids, decoder_input_ids=decoder_input_ids, labels=labels) #forward
+
+- Generation
+
+    While generating the target text set the `decoder_start_token_id` to the target language id. 
+    The following example shows how to translate English to Romanian using the ```facebook/mbart-large-en-ro``` model.
+
+::
+
+    from transformers import MBartForConditionalGeneration, MBartTokenizer
+    model = MBartForConditionalGeneration.from_pretrained("facebook/mbart-large-en-ro")
+    tokenizer = MBartTokenizer.from_pretrained("facebook/mbart-large-en-ro")
+    article = "UN Chief Says There Is No Military Solution in Syria"
+    batch = tokenizer.prepare_seq2seq_batch(src_texts=[article], src_lang="en_XX")
+    translated_tokens = model.generate(**batch, decoder_start_token_id=tokenizer.lang_code_to_id["ro_RO"])
+    translation = tokenizer.batch_decode(translated_tokens, skip_special_tokens=True)[0]
+    assert translation == "Şeful ONU declară că nu există o soluţie militară în Siria"
+
+
 MBartConfig
 ~~~~~~~~~~~~~~~~~~~~~
 

docs/source/model_doc/pegasus.rst

@@ -8,18 +8,19 @@ file a `Github Issue <https://github.com/huggingface/transformers/issues/new?ass
 Overview
 ~~~~~~~~~~~~~~~~~~~~~
 
-The Pegasus model was `proposed <https://arxiv.org/abs/1910.13461>`_ by Jingqing Zhang, Yao Zhao, Mohammad Saleh and Peter J. Liu on Dec 18, 2019.
+The Pegasus model was proposed in `PEGASUS: Pre-training with Extracted Gap-sentences for
+Abstractive Summarization <https://arxiv.org/pdf/1912.08777.pdf>`_ by Jingqing Zhang, Yao Zhao, Mohammad Saleh and Peter J. Liu on Dec 18, 2019.
 According to the abstract,
 
 - Pegasus' pretraining task is intentionally similar to summarization: important sentences are removed/masked from an input document and are generated together as one output sequence from the remaining sentences, similar to an extractive summary.
 - Pegasus achieves SOTA summarization performance on all 12 downstream tasks, as measured by ROUGE and human eval.
 
-The Authors' code can be found `here <https://github.com/google-research/pegasus>`_
+The Authors' code can be found `here <https://github.com/google-research/pegasus>`_.
 
 
 Checkpoints
 ~~~~~~~~~~~
-The `checkpoints <https://huggingface.co/models?search=pegasus>`_ all checkpoints are finetuned for summarization, besides ``pegasus-large``, whence the other checkpoints are finetuned.
+All the `checkpoints <https://huggingface.co/models?search=pegasus>`_ are finetuned for summarization, besides ``pegasus-large``, whence the other checkpoints are finetuned.
 - Each checkpoint is 2.2 GB on disk and 568M parameters.
 - FP16 is not supported (help/ideas on this appreciated!).
 - Summarizing xsum in fp32 takes about 400ms/sample, with default parameters on a v100 GPU.
@@ -47,6 +48,7 @@ Usage Example
 .. code-block:: python
 
     from transformers import PegasusForConditionalGeneration, PegasusTokenizer
+    import torch
     src_text = [
         """ PG&E stated it scheduled the blackouts in response to forecasts for high winds amid dry conditions. The aim is to reduce the risk of wildfires. Nearly 800 thousand customers were scheduled to be affected by the shutoffs which were expected to last through at least midday tomorrow."""
     ]
@@ -58,7 +60,7 @@ Usage Example
     batch = tokenizer.prepare_seq2seq_batch(src_text, truncation=True, padding='longest').to(torch_device)
     translated = model.generate(**batch)
     tgt_text = tokenizer.batch_decode(translated, skip_special_tokens=True)
-    assert tgt_text[0] == "California's largest electricity provider has turned off power to tens of thousands of customers."
+    assert tgt_text[0] == "California's largest electricity provider has turned off power to hundreds of thousands of customers."
 
 PegasusForConditionalGeneration
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

docs/source/model_doc/xlmroberta.rst

@@ -56,6 +56,13 @@ XLMRobertaModel
     :members:
 
 
+XLMRobertaForCausalLM
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.XLMRobertaForCausalLM
+    :members:
+
+
 XLMRobertaForMaskedLM
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -130,4 +137,4 @@ TFXLMRobertaForQuestionAnswering
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. autoclass:: transformers.TFXLMRobertaForQuestionAnswering
-    :members:
+    :members:

docs/source/model_sharing.rst

@@ -136,6 +136,13 @@ Then log in using the same credentials as on huggingface.co. To upload your mode
 
 This will upload the folder containing the weights, tokenizer and configuration we prepared in the previous section.
 
+By default you will be prompted to confirm that you want these files to be uploaded. If you are uploading multiple models and need to script that process, you can add `-y` to bypass the prompt. For example:
+
+::
+
+    transformers-cli upload -y path/to/awesome-name-you-picked/
+
+
 If you want to upload a single file (a new version of your model, or the other framework checkpoint you want to add),
 just type:
 

docs/source/model_summary.rst

@@ -1,11 +1,11 @@
 Summary of the models
 ================================================
 
-This is a summary of the models available in 🤗 Transformers. It assumes you’re familiar with the original 
-`transformer model <https://arxiv.org/abs/1706.03762>`_. For a gentle introduction check the `annotated transformer 
+This is a summary of the models available in 🤗 Transformers. It assumes you’re familiar with the original
+`transformer model <https://arxiv.org/abs/1706.03762>`_. For a gentle introduction check the `annotated transformer
 <http://nlp.seas.harvard.edu/2018/04/03/attention.html>`_. Here we focus on the high-level differences between the
-models. You can check them more in detail in their respective documentation. Also checkout the 
-:doc:`pretrained model page </pretrained_models>` to see the checkpoints available for each type of model and all `the 
+models. You can check them more in detail in their respective documentation. Also checkout the
+:doc:`pretrained model page </pretrained_models>` to see the checkpoints available for each type of model and all `the
 community models <https://huggingface.co/models>`_.
 
 Each one of the models in the library falls into one of the following categories:
@@ -14,38 +14,39 @@ Each one of the models in the library falls into one of the following categories
   * :ref:`autoencoding-models`
   * :ref:`seq-to-seq-models`
   * :ref:`multimodal-models`
+  * :ref:`retrieval-based-models`
 
-Autoregressive models are pretrained on the classic language modeling task: guess the next token having read all the 
-previous ones. They correspond to the decoder of the original transformer model, and a mask is used on top of the full 
-sentence so that the attention heads can only see what was before in the next, and not what’s after. Although those 
-models can be fine-tuned and achieve great results on many tasks, the most natural application is text generation. 
+Autoregressive models are pretrained on the classic language modeling task: guess the next token having read all the
+previous ones. They correspond to the decoder of the original transformer model, and a mask is used on top of the full
+sentence so that the attention heads can only see what was before in the next, and not what’s after. Although those
+models can be fine-tuned and achieve great results on many tasks, the most natural application is text generation.
 A typical example of such models is GPT.
 
-Autoencoding models are pretrained by corrupting the input tokens in some way and trying to reconstruct the original 
-sentence. They correspond to the encoder of the original transformer model in the sense that they get access to the 
-full inputs without any mask. Those models usually build a bidirectional representation of the whole sentence. They can 
-be fine-tuned and achieve great results on many tasks such as text generation, but their most natural application is 
+Autoencoding models are pretrained by corrupting the input tokens in some way and trying to reconstruct the original
+sentence. They correspond to the encoder of the original transformer model in the sense that they get access to the
+full inputs without any mask. Those models usually build a bidirectional representation of the whole sentence. They can
+be fine-tuned and achieve great results on many tasks such as text generation, but their most natural application is
 sentence classification or token classification. A typical example of such models is BERT.
 
-Note that the only difference between autoregressive models and autoencoding models is in the way the model is 
+Note that the only difference between autoregressive models and autoencoding models is in the way the model is
 pretrained. Therefore, the same architecture can be used for both autoregressive and autoencoding models. When a given
-model has been used for both pretraining, we have put it in the category corresponding to the article it was first
+model has been used for both types of pretraining, we have put it in the category corresponding to the article where it was first
 introduced.
 
-Sequence-to-sequence models use both the encoder and the decoder of the original transformer, either for translation 
-tasks or by transforming other tasks to sequence-to-sequence problems. They can be fine-tuned to many tasks but their 
-most natural applications are translation, summarization and question answering. The original transformer model is an 
+Sequence-to-sequence models use both the encoder and the decoder of the original transformer, either for translation
+tasks or by transforming other tasks to sequence-to-sequence problems. They can be fine-tuned to many tasks but their
+most natural applications are translation, summarization and question answering. The original transformer model is an
 example of such a model (only for translation), T5 is an example that can be fine-tuned on other tasks.
 
-Multimodal models mix text inputs with other kinds (like image) and are more specific to a given task.
+Multimodal models mix text inputs with other kinds (e.g. images) and are more specific to a given task.
 
 .. _autoregressive-models:
 
 Autoregressive models
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-As mentioned before, these models rely on the decoder part of the original transformer and use an attention mask so 
-that at each position, the model can only look at the tokens before in the attention heads.
+As mentioned before, these models rely on the decoder part of the original transformer and use an attention mask so
+that at each position, the model can only look at the tokens before the attention heads.
 
 Original GPT
 ----------------------------------------------
@@ -59,12 +60,12 @@ Original GPT
        <img alt="Doc" src="https://img.shields.io/badge/Model_documentation-openai--gpt-blueviolet">
    </a>
 
-`Improving Language Understanding by Generative Pre-Training <https://cdn.openai.com/research-covers/language-unsupervised/language_understanding_paper.pdf>`_, 
+`Improving Language Understanding by Generative Pre-Training <https://cdn.openai.com/research-covers/language-unsupervised/language_understanding_paper.pdf>`_,
 Alec Radford et al.
 
 The first autoregressive model based on the transformer architecture, pretrained on the Book Corpus dataset.
 
-The library provides versions of the model for language modeling and multitask language modeling/multiple choice 
+The library provides versions of the model for language modeling and multitask language modeling/multiple choice
 classification.
 
 GPT-2
@@ -79,13 +80,13 @@ GPT-2
        <img alt="Doc" src="https://img.shields.io/badge/Model_documentation-gpt2-blueviolet">
    </a>
 
-`Language Models are Unsupervised Multitask Learners <https://d4mucfpksywv.cloudfront.net/better-language-models/language_models_are_unsupervised_multitask_learners.pdf>`_, 
+`Language Models are Unsupervised Multitask Learners <https://d4mucfpksywv.cloudfront.net/better-language-models/language_models_are_unsupervised_multitask_learners.pdf>`_,
 Alec Radford et al.
 
-A bigger and better version of GPT, pretrained on WebText (web pages from outgoing links in Reddit with 3 karmas or 
+A bigger and better version of GPT, pretrained on WebText (web pages from outgoing links in Reddit with 3 karmas or
 more).
 
-The library provides versions of the model for language modeling and multitask language modeling/multiple choice 
+The library provides versions of the model for language modeling and multitask language modeling/multiple choice
 classification.
 
 CTRL
@@ -100,11 +101,11 @@ CTRL
        <img alt="Doc" src="https://img.shields.io/badge/Model_documentation-ctrl-blueviolet">
    </a>
 
-`CTRL: A Conditional Transformer Language Model for Controllable Generation <https://arxiv.org/abs/1909.05858>`_, 
+`CTRL: A Conditional Transformer Language Model for Controllable Generation <https://arxiv.org/abs/1909.05858>`_,
 Nitish Shirish Keskar et al.
 
-Same as the GPT model but adds the idea of control codes. Text is generated from a prompt (can be empty) and one (or 
-several) of those control codes which are then used to influence the text generation: generate with the style of 
+Same as the GPT model but adds the idea of control codes. Text is generated from a prompt (can be empty) and one (or
+several) of those control codes which are then used to influence the text generation: generate with the style of
 wikipedia article, a book or a movie review.
 
 The library provides a version of the model for language modeling only.
@@ -121,19 +122,19 @@ Transformer-XL
        <img alt="Doc" src="https://img.shields.io/badge/Model_documentation-transfo--xl-blueviolet">
    </a>
 
-`Transformer-XL: Attentive Language Models Beyond a Fixed-Length Context <https://arxiv.org/abs/1901.02860>`_, 
+`Transformer-XL: Attentive Language Models Beyond a Fixed-Length Context <https://arxiv.org/abs/1901.02860>`_,
 Zihang Dai et al.
 
-Same as a regular GPT model, but introduces a recurrence mechanism for two consecutive segments (similar to a regular 
-RNNs with two consecutive inputs). In this context, a segment is a number of consecutive tokens (for instance 512) that 
+Same as a regular GPT model, but introduces a recurrence mechanism for two consecutive segments (similar to a regular
+RNNs with two consecutive inputs). In this context, a segment is a number of consecutive tokens (for instance 512) that
 may span across multiple documents, and segments are fed in order to the model.
 
-Basically, the hidden states of the previous segment are concatenated to the current input to compute the attention 
-scores. This allows the model to pay attention to information that was in the previous segment as well as the current 
+Basically, the hidden states of the previous segment are concatenated to the current input to compute the attention
+scores. This allows the model to pay attention to information that was in the previous segment as well as the current
 one. By stacking multiple attention layers, the receptive field can be increased to multiple previous segments.
 
-This changes the positional embeddings to positional relative embeddings (as the regular positional embeddings would 
-give the same results in the current input and the current hidden state at a given position) and needs to make some 
+This changes the positional embeddings to positional relative embeddings (as the regular positional embeddings would
+give the same results in the current input and the current hidden state at a given position) and needs to make some
 adjustments in the way attention scores are computed.
 
 The library provides a version of the model for language modeling only.
@@ -155,16 +156,16 @@ Reformer
 `Reformer: The Efficient Transformer <https://arxiv.org/abs/2001.04451>`_,
 Nikita Kitaev et al .
 
-An autoregressive transformer model with lots of tricks to reduce memory footprint and compute time. Those tricks 
+An autoregressive transformer model with lots of tricks to reduce memory footprint and compute time. Those tricks
 include:
 
-  * Use :ref:`Axial position encoding <axial-pos-encoding>` (see below for more details). It’s a mechanism to avoid 
-    having a huge positional encoding matrix (when the sequence length is very big) by factorizing it in smaller 
+  * Use :ref:`Axial position encoding <axial-pos-encoding>` (see below for more details). It’s a mechanism to avoid
+    having a huge positional encoding matrix (when the sequence length is very big) by factorizing it into smaller
     matrices.
-  * Replace traditional attention by :ref:`LSH (local-sensitive hashing) attention <lsh-attention>` (see below for more 
-    details). It's a technique to avoid compute the full product query-key in the attention layers.
-  * Avoid storing the intermediate results of each layer by using reversible transformer layers to obtain them during 
-    the backward pass (subtracting the residuals from the input of the next layer gives them back) or recomputing them 
+  * Replace traditional attention by :ref:`LSH (local-sensitive hashing) attention <lsh-attention>` (see below for more
+    details). It's a technique to avoid computing the full product query-key in the attention layers.
+  * Avoid storing the intermediate results of each layer by using reversible transformer layers to obtain them during
+    the backward pass (subtracting the residuals from the input of the next layer gives them back) or recomputing them
     for results inside a given layer (less efficient than storing them but saves memory).
   * Compute the feedforward operations by chunks and not on the whole batch.
 
@@ -190,14 +191,14 @@ XLNet
 `XLNet: Generalized Autoregressive Pretraining for Language Understanding <https://arxiv.org/abs/1906.08237>`_,
 Zhilin Yang et al.
 
-XLNet is not a traditional autoregressive model but uses a training strategy that builds on that. It permutes the 
-tokens in the sentence, then allows the model to use the last n tokens to predict the token n+1. Since this is all done 
-with a mask, the sentence is actually fed in the model in the right order, but instead of masking the first n tokens 
+XLNet is not a traditional autoregressive model but uses a training strategy that builds on that. It permutes the
+tokens in the sentence, then allows the model to use the last n tokens to predict the token n+1. Since this is all done
+with a mask, the sentence is actually fed in the model in the right order, but instead of masking the first n tokens
 for n+1, XLNet uses a mask that hides the previous tokens in some given permutation of 1,...,sequence length.
 
-XLNet also uses the same recurrence mechanism as Transformer-XL to build long-term dependencies. 
+XLNet also uses the same recurrence mechanism as Transformer-XL to build long-term dependencies.
 
-The library provides a version of the model for language modeling, token classification, sentence classification, 
+The library provides a version of the model for language modeling, token classification, sentence classification,
 multiple choice classification and question answering.
 
 .. _autoencoding-models:
@@ -206,8 +207,7 @@ Autoencoding models
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 As mentioned before, these models rely on the encoder part of the original transformer and use no mask so the model can
-look at all the tokens in the attention heads. For pretraining, inputs are a corrupted version of the sentence, usually 
-obtained by masking tokens, and targets are the original sentences.
+look at all the tokens in the attention heads. For pretraining, targets are the original sentences and inputs are their corrupted versions.
 
 BERT
 ----------------------------------------------
@@ -224,18 +224,18 @@ BERT
 `BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding <https://arxiv.org/abs/1810.04805>`_,
 Jacob Devlin et al.
 
-Corrupts the inputs by using random masking, more precisely, during pretraining, a given percentage of tokens (usually 
-15%) are masked by
- 
+Corrupts the inputs by using random masking, more precisely, during pretraining, a given percentage of tokens (usually
+15%) is masked by:
+
   * a special mask token with probability 0.8
   * a random token different from the one masked with probability 0.1
   * the same token with probability 0.1
 
-The model must predict the original sentence, but has a second objective: inputs are two sentences A and B (with a 
-separation token in between). With probability 50%, the sentences are consecutive in the corpus, in the remaining 50% 
+The model must predict the original sentence, but has a second objective: inputs are two sentences A and B (with a
+separation token in between). With probability 50%, the sentences are consecutive in the corpus, in the remaining 50%
 they are not related. The model has to predict if the sentences are consecutive or not.
 
-The library provides a version of the model for language modeling (traditional or masked), next sentence prediction, 
+The library provides a version of the model for language modeling (traditional or masked), next sentence prediction,
 token classification, sentence classification, multiple choice classification and question answering.
 
 ALBERT
@@ -255,16 +255,16 @@ Zhenzhong Lan et al.
 
 Same as BERT but with a few tweaks:
 
-  * Embedding size E is different from hidden size H justified because the embeddings are context independent (one 
-    embedding vector represents one token) whereas hidden states are context dependent (one hidden state represents a 
-    sequence of tokens) so it's more logical to have H >> E. Als, the embedding matrix is large since it's V x E (V 
+  * Embedding size E is different from hidden size H justified because the embeddings are context independent (one
+    embedding vector represents one token), whereas hidden states are context dependent (one hidden state represents a
+    sequence of tokens) so it's more logical to have H >> E. Also, the embedding matrix is large since it's V x E (V
     being the vocab size). If E < H, it has less parameters.
   * Layers are split in groups that share parameters (to save memory).
-  * Next sentence prediction is replaced by a sentence ordering prediction: in the inputs, we have two sentences A et B 
-    (that are consecutive) and we either feed A followed by B or B followed by A. The model must predict if they have 
+  * Next sentence prediction is replaced by a sentence ordering prediction: in the inputs, we have two sentences A and B
+    (that are consecutive) and we either feed A followed by B or B followed by A. The model must predict if they have
     been swapped or not.
 
-The library provides a version of the model for masked language modeling, token classification, sentence 
+The library provides a version of the model for masked language modeling, token classification, sentence
 classification, multiple choice classification and question answering.
 
 RoBERTa
@@ -284,13 +284,13 @@ Yinhan Liu et al.
 
 Same as BERT with better pretraining tricks:
 
-  * dynamic masking: tokens are masked differently at each epoch whereas BERT does it once and for all
-  * no NSP (next sentence prediction) loss and instead of putting just two sentences together, put a chunk of 
-    contiguous texts together to reach 512 tokens (so sentences in in an order than may span other several documents)
+  * dynamic masking: tokens are masked differently at each epoch, whereas BERT does it once and for all
+  * no NSP (next sentence prediction) loss and instead of putting just two sentences together, put a chunk of
+    contiguous texts together to reach 512 tokens (so the sentences are in an order than may span several documents)
   * train with larger batches
   * use BPE with bytes as a subunit and not characters (because of unicode characters)
 
-The library provides a version of the model for masked language modeling, token classification, sentence 
+The library provides a version of the model for masked language modeling, token classification, sentence
 classification, multiple choice classification and question answering.
 
 DistilBERT
@@ -308,14 +308,14 @@ DistilBERT
 `DistilBERT, a distilled version of BERT: smaller, faster, cheaper and lighter <https://arxiv.org/abs/1910.01108>`_,
 Victor Sanh et al.
 
-Same as BERT but smaller. Trained by distillation of the pretrained BERT model, meaning it's been trained to predict 
+Same as BERT but smaller. Trained by distillation of the pretrained BERT model, meaning it's been trained to predict
 the same probabilities as the larger model. The actual objective is a combination of:
 
   * finding the same probabilities as the teacher model
   * predicting the masked tokens correctly (but no next-sentence objective)
   * a cosine similarity between the hidden states of the student and the teacher model
 
-The library provides a version of the model for masked language modeling, token classification, sentence classification 
+The library provides a version of the model for masked language modeling, token classification, sentence classification
 and question answering.
 
 XLM
@@ -332,25 +332,24 @@ XLM
 
 `Cross-lingual Language Model Pretraining <https://arxiv.org/abs/1901.07291>`_, Guillaume Lample and Alexis Conneau
 
-A transformer model trained on several languages. There are three different type of training for this model and the 
+A transformer model trained on several languages. There are three different type of training for this model and the
 library provides checkpoints for all of them:
 
-  * Causal language modeling (CLM) which is the traditional autoregressive training (so this model could be in the 
-    previous section as well). One of the languages is selected for each training sample, and the model input is a 
-    sentence of 256 tokens that may span on several documents in one one those languages.
-  * Masked language modeling (MLM) which is like RoBERTa. One of the languages is selected for each training sample, 
-    and the model input is a sentence of 256 tokens that may span on several documents in one one those languages, with
+  * Causal language modeling (CLM) which is the traditional autoregressive training (so this model could be in the
+    previous section as well). One of the languages is selected for each training sample, and the model input is a
+    sentence of 256 tokens, that may span over several documents in one of those languages.
+  * Masked language modeling (MLM) which is like RoBERTa. One of the languages is selected for each training sample,
+    and the model input is a sentence of 256 tokens, that may span over several documents in one of those languages, with
     dynamic masking of the tokens.
-  * A combination of MLM and translation language modeling (TLM). This consists of concatenating a sentence in two 
-    different languages, with random masking. To predict one of the masked token, the model can use both the 
-    surrounding context in language 1 as well as the context given by language 2.
+  * A combination of MLM and translation language modeling (TLM). This consists of concatenating a sentence in two
+    different languages, with random masking. To predict one of the masked tokens, the model can use both, the
+    surrounding context in language 1 and the context given by language 2.
 
 Checkpoints refer to which method was used for pretraining by having `clm`, `mlm` or `mlm-tlm` in their names. On top
 of positional embeddings, the model has language embeddings. When training using MLM/CLM, this gives the model an
-indication of the language used, and when training using MLM+TLM, an indication of which part of the input is in which
-language.
+indication of the language used, and when training using MLM+TLM, an indication of the language used for each part.
 
-The library provides a version of the model for language modeling, token classification, sentence classification and 
+The library provides a version of the model for language modeling, token classification, sentence classification and
 question answering.
 
 XLM-RoBERTa
@@ -365,14 +364,14 @@ XLM-RoBERTa
        <img alt="Doc" src="https://img.shields.io/badge/Model_documentation-xlm--roberta-blueviolet">
    </a>
 
-`Unsupervised Cross-lingual Representation Learning at Scale <https://arxiv.org/abs/1911.02116>`_, Alexis Conneau et 
+`Unsupervised Cross-lingual Representation Learning at Scale <https://arxiv.org/abs/1911.02116>`_, Alexis Conneau et
 al.
 
-Uses RoBERTa tricks on the XLM approach, but does not use the translation language modeling objective, only using 
-masked language modeling on sentences coming from one language. However, the model is trained on many more languages 
+Uses RoBERTa tricks on the XLM approach, but does not use the translation language modeling objective. It only uses
+masked language modeling on sentences coming from one language. However, the model is trained on many more languages
 (100) and doesn't use the language embeddings, so it's capable of detecting the input language by itself.
 
-The library provides a version of the model for masked language modeling, token classification, sentence 
+The library provides a version of the model for masked language modeling, token classification, sentence
 classification, multiple choice classification and question answering.
 
 FlauBERT
@@ -405,18 +404,50 @@ ELECTRA
        <img alt="Doc" src="https://img.shields.io/badge/Model_documentation-electra-blueviolet">
    </a>
 
-`ELECTRA: Pre-training Text Encoders as Discriminators Rather Than Generators <https://arxiv.org/abs/2003.10555>`_, 
+`ELECTRA: Pre-training Text Encoders as Discriminators Rather Than Generators <https://arxiv.org/abs/2003.10555>`_,
 Kevin Clark et al.
 
-ELECTRA is a transformer model pretrained with the use of another (small) masked language model. The inputs are 
-corrupted by that language model, which takes an input text that is randomly masked and outputs a text in which ELECTRA 
-has to predict which token is an original and which one has been replaced. Like for GAN training, the small language 
-model is trained for a few steps (but with the original texts as objective, not to fool the ELECTRA model like in a 
+ELECTRA is a transformer model pretrained with the use of another (small) masked language model. The inputs are
+corrupted by that language model, which takes an input text that is randomly masked and outputs a text in which ELECTRA
+has to predict which token is an original and which one has been replaced. Like for GAN training, the small language
+model is trained for a few steps (but with the original texts as objective, not to fool the ELECTRA model like in a
 traditional GAN setting) then the ELECTRA model is trained for a few steps.
 
-The library provides a version of the model for masked language modeling, token classification and sentence 
+The library provides a version of the model for masked language modeling, token classification and sentence
 classification.
 
+Funnel Transformer
+----------------------------------------------
+
+.. raw:: html
+
+   <a href="https://huggingface.co/models?filter=funnel">
+       <img alt="Models" src="https://img.shields.io/badge/All_model_pages-funnel-blueviolet">
+   </a>
+   <a href="model_doc/funnel.html">
+       <img alt="Doc" src="https://img.shields.io/badge/Model_documentation-funnel-blueviolet">
+   </a>
+
+`Funnel-Transformer: Filtering out Sequential Redundancy for Efficient Language Processing
+<https://arxiv.org/abs/2006.03236>`_, Zihang Dai et al.
+
+Funnel Transformer is a transformer model using pooling, a bit like a ResNet model: layers are grouped in blocks, and
+at the beginning of each block (except the first one), the hidden states are pooled among the sequence dimension. This
+way, their length is divided by 2, which speeds up the computation of the next hidden states. All pretrained models
+have three blocks, which means the final hidden state has a sequence length that is one fourth of the original sequence
+length.
+
+For tasks such as classification, this is not a problem, but for tasks like masked language modeling or token
+classification, we need a hidden state with the same sequence length as the original input. In those cases, the final
+hidden states are upsampled to the input sequence length and go through two additional layers. That's why there are two
+versions of each checkpoint. The version suffixed with "-base" contains only the three blocks, while the version
+without that suffix contains the three blocks and the upsampling head with its additional layers.
+
+The pretrained models available use the same pretraining objective as ELECTRA.
+
+The library provides a version of the model for masked language modeling, token classification, sentence
+classification, multiple choice classification and question answering.
+
 .. _longformer:
 
 Longformer
@@ -433,9 +464,9 @@ Longformer
 
 `Longformer: The Long-Document Transformer <https://arxiv.org/abs/2004.05150>`_, Iz Beltagy et al.
 
-A transformer model replacing the attention matrices by sparse matrices to go faster. Often, the local context (e.g., 
-what are the two tokens left and right?) is enough to take action for a given token. Some preselected input tokens are 
-still given global attention, but the attention matrix has way less parameters, resulting in a speed-up. See the 
+A transformer model replacing the attention matrices by sparse matrices to go faster. Often, the local context (e.g.,
+what are the two tokens left and right?) is enough to take action for a given token. Some preselected input tokens are
+still given global attention, but the attention matrix has way less parameters, resulting in a speed-up. See the
 :ref:`local attention section <local-attention>` for more information.
 
 It is pretrained the same way a RoBERTa otherwise.
@@ -443,7 +474,7 @@ It is pretrained the same way a RoBERTa otherwise.
 **Note:** This model could be very well be used in an autoregressive setting, there is no checkpoint for such a
 pretraining yet, though.
 
-The library provides a version of the model for masked language modeling, token classification, sentence 
+The library provides a version of the model for masked language modeling, token classification, sentence
 classification, multiple choice classification and question answering.
 
 .. _seq-to-seq-models:
@@ -465,21 +496,46 @@ BART
        <img alt="Doc" src="https://img.shields.io/badge/Model_documentation-bart-blueviolet">
    </a>
 
-`BART: Denoising Sequence-to-Sequence Pre-training for Natural Language Generation, Translation, and Comprehension 
+`BART: Denoising Sequence-to-Sequence Pre-training for Natural Language Generation, Translation, and Comprehension
 <https://arxiv.org/abs/1910.13461>`_, Mike Lewis et al.
 
-Sequence-to-sequence model with an encoder and a decoder. Encoder is fed a corrupted version of the tokens, decoder is 
-fed the tokens (but has a mask to hide the future words like a regular transformers decoder). For the encoder, on the 
+Sequence-to-sequence model with an encoder and a decoder. Encoder is fed a corrupted version of the tokens, decoder is
+fed the original tokens (but has a mask to hide the future words like a regular transformers decoder). For the encoder, on the
 pretraining tasks, a composition of the following transformations are applied:
 
   * mask random tokens (like in BERT)
   * delete random tokens
   * mask a span of k tokens with a single mask token (a span of 0 tokens is an insertion of a mask token)
   * permute sentences
-  * rotate the document to make it start by a specific token
+  * rotate the document to make it start at a specific token
 
 The library provides a version of this model for conditional generation and sequence classification.
 
+Pegasus
+----------------------------------------------
+
+.. raw:: html
+
+   <a href="https://huggingface.co/models?filter=pegasus">
+       <img alt="Models" src="https://img.shields.io/badge/All_model_pages-pegasus-blueviolet">
+   </a>
+   <a href="model_doc/pegasus.html">
+       <img alt="Doc" src="https://img.shields.io/badge/Model_documentation-pegasus-blueviolet">
+   </a>
+
+`PEGASUS: Pre-training with Extracted Gap-sentences forAbstractive Summarization 
+<https://arxiv.org/pdf/1912.08777.pdf>`_, Jingqing Zhang, Yao Zhao, Mohammad Saleh and Peter J. Liu on Dec 18, 2019.
+
+Sequence-to-sequence model with the same encoder-decoder model architecture as BART. Pegasus is pre-trained jointly on two self-supervised objective functions: Masked Language Modeling (MLM) and a novel summarization specific pre-training objective, called Gap Sentence Generation (GSG).
+
+  * MLM: encoder input tokens are randomely replaced by a mask tokens and have to be predicted by the encoder (like in BERT)
+  * GSG: whole encoder input sentences are replaced by a second mask token and fed to the decoder, but which has a causal mask to hide the future words like a regular auto-regressive transformer decoder.
+
+In contrast to BART, Pegasus' pretraining task is intentionally similar to summarization: important sentences are masked and are generated together as one output sequence from the remaining sentences, similar to an extractive summary.
+
+The library provides a version of this model for conditional generation, which should be used for summarization.
+
+
 MarianMT
 ----------------------------------------------
 
@@ -510,47 +566,71 @@ T5
        <img alt="Doc" src="https://img.shields.io/badge/Model_documentation-t5-blueviolet">
    </a>
 
-`Exploring the Limits of Transfer Learning with a Unified Text-to-Text Transformer <https://arxiv.org/abs/1910.10683>`_, 
+`Exploring the Limits of Transfer Learning with a Unified Text-to-Text Transformer <https://arxiv.org/abs/1910.10683>`_,
 Colin Raffel et al.
 
-Uses the traditional transformer model (except a slight change with the positional embeddings, which are learned at 
-each layer). To be able to operate on all NLP tasks, it transforms them in text-to-text problems by using certain 
-prefixes: “Summarize: …”, “question: …”, “translate English to German: …” and so forth.
+Uses the traditional transformer model (with a slight change in the positional embeddings, which are learned at
+each layer). To be able to operate on all NLP tasks, it transforms them into text-to-text problems by using specific
+prefixes: “summarize: ”, “question: ”, “translate English to German: ” and so forth.
 
-The pretraining includes both supervised and self-supervised training. Supervised training is conducted on downstream 
-tasks provided by the GLUE and SuperGLUE benchmarks (changing them to text-to-text tasks as explained above).
+The pretraining includes both supervised and self-supervised training. Supervised training is conducted on downstream
+tasks provided by the GLUE and SuperGLUE benchmarks (converting them into text-to-text tasks as explained above).
 
-Self-supervised training consists of corrupted pretrained, which means randomly removing 15% of the tokens and 
-replacing them by individual sentinel tokens (if several consecutive tokens are marked for removal, they are replaced 
-by one single sentinel token). The input of the encoder is the corrupted sentence, the input of the decoder the 
+Self-supervised training uses corrupted tokens, by randomly removing 15% of the tokens and
+replacing them with individual sentinel tokens (if several consecutive tokens are marked for removal, the whole group is replaced with a single sentinel token). The input of the encoder is the corrupted sentence, the input of the decoder is the
 original sentence and the target is then the dropped out tokens delimited by their sentinel tokens.
 
-For instance, if we have the sentence “My dog is very cute .”, and we decide to remove the token dog, is and cute, the 
-input becomes “My <x> very <y> .” and the target is “<x> dog is <y> . <z>”
+For instance, if we have the sentence “My dog is very cute .”, and we decide to remove the tokens: "dog", "is" and "cute", the encoder
+input becomes “My <x> very <y> .” and the target input becomes “<x> dog is <y> cute .<z>”
 
 The library provides a version of this model for conditional generation.
 
+MBart
+----------------------------------------------
+
+.. raw:: html
+
+   <a href="https://huggingface.co/models?filter=mbart">
+       <img alt="Models" src="https://img.shields.io/badge/All_model_pages-mbart-blueviolet">
+   </a>
+   <a href="model_doc/mbart.html">
+       <img alt="Doc" src="https://img.shields.io/badge/Model_documentation-mbart-blueviolet">
+   </a>
+
+`Multilingual Denoising Pre-training for Neural Machine Translation <https://arxiv.org/abs/2001.08210>`_ by Yinhan Liu, Jiatao Gu, Naman Goyal, Xian Li, Sergey Edunov
+Marjan Ghazvininejad, Mike Lewis, Luke Zettlemoyer.
+
+The model architecture and pre-training objective is same as BART, but MBart is trained on 25 languages 
+and is intended for supervised and unsupervised machine translation. MBart is one of the first methods 
+for pre-training a complete sequence-to-sequence model by denoising full texts in multiple languages,
+
+The library provides a version of this model for conditional generation.
+
+The `mbart-large-en-ro checkpoint <https://huggingface.co/facebook/mbart-large-en-ro>`_ can be used for english -> romanian translation.
+
+The `mbart-large-cc25 <https://huggingface.co/facebook/mbart-large-cc25>`_ checkpoint can be finetuned for other translation and summarization tasks, using code in ```examples/seq2seq/``` , but is not very useful without finetuning.
+
 .. _multimodal-models:
 
 Multimodal models
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-There is one multimodal model in the library which has not been pretrained in the self-supervised fashion like the 
+There is one multimodal model in the library which has not been pretrained in the self-supervised fashion like the
 others.
 
 MMBT
 ----------------------------------------------
 
-`Supervised Multimodal Bitransformers for Classifying Images and Text <https://arxiv.org/abs/1909.02950>`_, Douwe Kiela 
+`Supervised Multimodal Bitransformers for Classifying Images and Text <https://arxiv.org/abs/1909.02950>`_, Douwe Kiela
 et al.
 
-A transformers model used in multimodal settings, combining a text and an image to make predictions. The transformer 
-model takes as inputs the embeddings of the tokenized text and a the final activations of a pretrained resnet on the 
-images (after the pooling layer) that goes through a linear layer (to go from number of features at the end of the 
+A transformers model used in multimodal settings, combining a text and an image to make predictions. The transformer
+model takes as inputs the embeddings of the tokenized text and the final activations of a pretrained on images resnet
+(after the pooling layer) that goes through a linear layer (to go from number of features at the end of the
 resnet to the hidden state dimension of the transformer).
 
-The different inputs are concatenated, and on top of the positional embeddings, a segment embedding is added to let the 
-model know which part of the input vector corresponds to the text or the image.
+The different inputs are concatenated, and on top of the positional embeddings, a segment embedding is added to let the
+model know which part of the input vector corresponds to the text and which to the image.
 
 The pretrained model only works for classification.
 
@@ -558,45 +638,79 @@ The pretrained model only works for classification.
     More information in this :doc:`model documentation </model_doc/mmbt.html>`.
     TODO: write this page
 
+.. _retrieval-based-models:
+
+Retrieval-based models
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Some models use documents retrieval during (pre)training and inference for open-domain question answering, for example.
+
+
+DPR
+----------------------------------------------
+
+.. raw:: html
+
+   <a href="https://huggingface.co/models?filter=dpr">
+       <img alt="Models" src="https://img.shields.io/badge/All_model_pages-dpr-blueviolet">
+   </a>
+   <a href="model_doc/ctrl.dpr">
+       <img alt="Doc" src="https://img.shields.io/badge/Model_documentation-dpr-blueviolet">
+   </a>
+
+`Dense Passage Retrieval for Open-Domain Question Answering <https://arxiv.org/abs/2004.04906>`_,
+Vladimir Karpukhin et al.
+
+Dense Passage Retrieval (DPR) - is a set of tools and models for state-of-the-art open-domain question-answering research.
+
+
+DPR consists in three models:
+
+  * Question encoder: encode questions as vectors
+  * Context encoder: encode contexts as vectors
+  * Reader: extract the answer of the questions inside retrieved contexts, along with a relevance score (high if the inferred span actually answers the question).
+
+DPR's pipeline (not implemented yet) uses a retrieval step to find the top k contexts given a certain question, and then it calls the reader with the question and the retrieved documents to get the answer.
+
 More technical aspects
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Full vs sparse attention
 ----------------------------------------------
 
-Most transformer models use full attention in the sense that the attention matrix is square. It can be a big 
-computational bottleneck when you have long texts. Longformer and reformer are models that try to be more efficient and 
+Most transformer models use full attention in the sense that the attention matrix is square. It can be a big
+computational bottleneck when you have long texts. Longformer and reformer are models that try to be more efficient and
 use a sparse version of the attention matrix to speed up training.
 
 .. _lsh-attention:
 
 **LSH attention**
 
-:ref:`Reformer <reformer>` uses LSH attention. In the softmax(QK^t), only the biggest elements (in the softmax 
-dimension) of the matrix QK^t are going to give useful contributions. So for each query q in Q, we can only consider 
-the keys k in K that are close to q. A hash function is used to determine if q and k are close. The attention mask is 
-modified to mask the current token (except at the first position) because it will give a query and key equal (so very 
-similar to each other). Since the hash can be a bit random, several hash functions are used in practice (determined by 
-a n_rounds parameter) then are averaged together.
+:ref:`Reformer <reformer>` uses LSH attention. In the softmax(QK^t), only the biggest elements (in the softmax
+dimension) of the matrix QK^t are going to give useful contributions. So for each query q in Q, we can  consider only
+the keys k in K that are close to q. A hash function is used to determine if q and k are close. The attention mask is
+modified to mask the current token (except at the first position), because it will give a query and a key equal (so very
+similar to each other). Since the hash can be a bit random, several hash functions are used in practice (determined by
+a n_rounds parameter) and then are averaged together.
 
 .. _local-attention:
 
 **Local attention**
 
-:ref:`Longformer <longformer>` uses local attention: often, the local context (e.g., what are the two tokens left and 
-right?) is enough to take action for a given token. Also, by stacking attention layers that have a small window, the 
-last layer will have a receptive field of more than just the tokens on the window, allowing them to build a 
+:ref:`Longformer <longformer>` uses local attention: often, the local context (e.g., what are the two tokens to the left and
+right?) is enough to take action for a given token. Also, by stacking attention layers that have a small window, the
+last layer will have a receptive field of more than just the tokens in the window, allowing them to build a
 representation of the whole sentence.
 
-Some preselected input tokens are also given global attention: for those few tokens, the attention matrix can access 
-all tokens and this process is symmetric: all other tokens have access to those specific tokens (on top of the ones in 
+Some preselected input tokens are also given global attention: for those few tokens, the attention matrix can access
+all tokens and this process is symmetric: all other tokens have access to those specific tokens (on top of the ones in
 their local window). This is shown in Figure 2d of the paper, see below for a sample attention mask:
 
 .. image:: imgs/local_attention_mask.png
    :scale: 50 %
    :align: center
 
-Using those attention matrices with less parameters then allows the model to have inputs having a bigger sequence 
+Using those attention matrices with less parameters then allows the model to have inputs having a bigger sequence
 length.
 
 Other tricks
@@ -606,13 +720,10 @@ Other tricks
 
 **Axial positional encodings**
 
-:ref:`Reformer <reformer>` uses axial positional encodings: in traditional transformer models, the positional encoding 
-E is a matrix of size :math:`l` by :math:`d`, :math:`l` being the sequence length and :math:`d` the dimension of the 
-hidden state. If you have very long texts, this matrix can be huge and take way too much space on the GPU.
-
-To alleviate that, axial positional encodings consists in factorizing that big matrix E in two smaller matrices E1 and 
+:ref:`Reformer <reformer>` uses axial positional encodings: in traditional transformer models, the positional encoding
+E is a matrix of size :math:`l` by :math:`d`, :math:`l` being the sequence length and :math:`d` the dimension of the
+hidden state. If you have very long texts, this matrix can be huge and take way too much space on the GPU. To alleviate that, axial positional encodings consist of factorizing that big matrix E in two smaller matrices E1 and
 E2, with dimensions :math:`l_{1} \times d_{1}` and :math:`l_{2} \times d_{2}`, such that :math:`l_{1} \times l_{2} = l`
-and :math:`d_{1} + d_{2} = d` (with the product for the lengths, this ends up being way smaller). The embedding for 
-time step :math:`j` in E is obtained by concatenating the embeddings for timestep :math:`j \% l1` in E1 and 
+and :math:`d_{1} + d_{2} = d` (with the product for the lengths, this ends up being way smaller). The embedding for
+time step :math:`j` in E is obtained by concatenating the embeddings for timestep :math:`j \% l1` in E1 and
 :math:`j // l1` in E2.
-

docs/source/philosophy.rst

@@ -45,12 +45,12 @@ A few other goals:
     - A simple/consistent way to add new tokens to the vocabulary and embeddings for fine-tuning.
     - Simple ways to mask and prune transformer heads.
 
-- Switch easily between PyTorch and TensorFlow 2.0, allowing training using one framwork and inference using another.
+- Switch easily between PyTorch and TensorFlow 2.0, allowing training using one framework and inference using another.
 
 Main concepts
 ~~~~~~~~~~~~~
 
-The library is build around three types of classes for each model:
+The library is built around three types of classes for each model:
 
 - **Model classes**  such as :class:`~transformers.BertModel`, which are 30+ PyTorch models 
   (`torch.nn.Module <https://pytorch.org/docs/stable/nn.html#torch.nn.Module>`__) or Keras models 
@@ -65,9 +65,9 @@ The library is build around three types of classes for each model:
 
 All these classes can be instantiated from pretrained instances and saved locally using two methods:
 
-- :obj:`from_pretrained()` let you instantiate a model/configuration/tokenizer from a pretrained version either
+- :obj:`from_pretrained()` lets you instantiate a model/configuration/tokenizer from a pretrained version either
   provided by the library itself (the suported models are provided in the list :doc:`here <pretrained_models>`
   or stored locally (or on a server) by the user,
-- :obj:`save_pretrained()` let you save a model/configuration/tokenizer locally so that it can be reloaded using
+- :obj:`save_pretrained()` lets you save a model/configuration/tokenizer locally so that it can be reloaded using
   :obj:`from_pretrained()`.
 

docs/source/preprocessing.rst

@@ -53,7 +53,6 @@ The tokenizer can decode a list of token ids in a proper sentence:
 
 As you can see, the tokenizer automatically added some special tokens that the model expect. Not all model need special
 tokens; for instance, if we had used` gtp2-medium` instead of `bert-base-cased` to create our tokenizer, we would have
-
 seen the same sentence as the original one here. You can disable this behavior (which is only advised if you have added
 those special tokens yourself) by passing ``add_special_tokens=False``.
 
@@ -285,6 +284,12 @@ The tokenizer also accept pre-tokenized inputs. This is particularly useful when
 predictions in `named entity recognition (NER) <https://en.wikipedia.org/wiki/Named-entity_recognition>`__ or
 `part-of-speech tagging (POS tagging) <https://en.wikipedia.org/wiki/Part-of-speech_tagging>`__.
 
+.. warning::
+
+    Pre-tokenized does not mean your inputs are already tokenized (you wouldn't need to pass them though the tokenizer
+    if that was the case) but just split into words (which is often the first step in subword tokenization algorithms
+    like BPE).
+
 If you want to use pre-tokenized inputs, just set :obj:`is_pretokenized=True` when passing your inputs to the
 tokenizer. For instance, we have:
 

docs/source/pretrained_models.rst

@@ -5,359 +5,406 @@ Here is the full list of the currently provided pretrained models together with
 
 For a list that includes community-uploaded models, refer to `https://huggingface.co/models <https://huggingface.co/models>`__.
 
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| Architecture      | Shortcut name                                              | Details of the model                                                                                                                  |
-+===================+============================================================+=======================================================================================================================================+
-| BERT              | ``bert-base-uncased``                                      | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on lower-cased English text.                                                                                                |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-large-uncased``                                     | | 24-layer, 1024-hidden, 16-heads, 340M parameters.                                                                                   |
-|                   |                                                            | | Trained on lower-cased English text.                                                                                                |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-base-cased``                                        | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on cased English text.                                                                                                      |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-large-cased``                                       | | 24-layer, 1024-hidden, 16-heads, 340M parameters.                                                                                   |
-|                   |                                                            | | Trained on cased English text.                                                                                                      |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-base-multilingual-uncased``                         | | (Original, not recommended) 12-layer, 768-hidden, 12-heads, 110M parameters.                                                        |
-|                   |                                                            | | Trained on lower-cased text in the top 102 languages with the largest Wikipedias                                                    |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/google-research/bert/blob/master/multilingual.md>`__).                                              |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-base-multilingual-cased``                           | | (New, **recommended**) 12-layer, 768-hidden, 12-heads, 110M parameters.                                                             |
-|                   |                                                            | | Trained on cased text in the top 104 languages with the largest Wikipedias                                                          |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/google-research/bert/blob/master/multilingual.md>`__).                                              |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-base-chinese``                                      | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on cased Chinese Simplified and Traditional text.                                                                           |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-base-german-cased``                                 | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on cased German text by Deepset.ai                                                                                          |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details on deepset.ai website <https://deepset.ai/german-bert>`__).                                                             |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-large-uncased-whole-word-masking``                  | | 24-layer, 1024-hidden, 16-heads, 340M parameters.                                                                                   |
-|                   |                                                            | | Trained on lower-cased English text using Whole-Word-Masking                                                                        |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/google-research/bert/#bert>`__).                                                                    |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-large-cased-whole-word-masking``                    | | 24-layer, 1024-hidden, 16-heads, 340M parameters.                                                                                   |
-|                   |                                                            | | Trained on cased English text using Whole-Word-Masking                                                                              |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/google-research/bert/#bert>`__).                                                                    |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-large-uncased-whole-word-masking-finetuned-squad``  | | 24-layer, 1024-hidden, 16-heads, 340M parameters.                                                                                   |
-|                   |                                                            | | The ``bert-large-uncased-whole-word-masking`` model fine-tuned on SQuAD                                                             |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see details of fine-tuning in the `example section <https://github.com/huggingface/transformers/tree/master/examples>`__).           |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-large-cased-whole-word-masking-finetuned-squad``    | | 24-layer, 1024-hidden, 16-heads, 340M parameters                                                                                    |
-|                   |                                                            | | The ``bert-large-cased-whole-word-masking`` model fine-tuned on SQuAD                                                               |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details of fine-tuning in the example section <https://huggingface.co/transformers/examples.html>`__)                           |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-base-cased-finetuned-mrpc``                         | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | The ``bert-base-cased`` model fine-tuned on MRPC                                                                                    |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details of fine-tuning in the example section <https://huggingface.co/transformers/examples.html>`__)                           |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-base-german-dbmdz-cased``                           | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on cased German text by DBMDZ                                                                                               |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details on dbmdz repository <https://github.com/dbmdz/german-bert>`__).                                                         |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``bert-base-german-dbmdz-uncased``                         | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on uncased German text by DBMDZ                                                                                             |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details on dbmdz repository <https://github.com/dbmdz/german-bert>`__).                                                         |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``cl-tohoku/bert-base-japanese``                           | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on Japanese text. Text is tokenized with MeCab and WordPiece and this requires some extra dependencies,                     |
-|                   |                                                            | | `fugashi <https://github.com/polm/fugashi>`__ which is a wrapper around `MeCab <https://taku910.github.io/mecab/>`__.               |
-|                   |                                                            | | Use ``pip install transformers["ja"]`` (or ``pip install -e .["ja"]`` if you install from source) to install them.                  |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details on cl-tohoku repository <https://github.com/cl-tohoku/bert-japanese>`__).                                               |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``cl-tohoku/bert-base-japanese-whole-word-masking``        | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on Japanese text. Text is tokenized with MeCab and WordPiece and this requires some extra dependencies,                     |
-|                   |                                                            | | `fugashi <https://github.com/polm/fugashi>`__ which is a wrapper around `MeCab <https://taku910.github.io/mecab/>`__.               |
-|                   |                                                            | | Use ``pip install transformers["ja"]`` (or ``pip install -e .["ja"]`` if you install from source) to install them.                  |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details on cl-tohoku repository <https://github.com/cl-tohoku/bert-japanese>`__).                                               |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``cl-tohoku/bert-base-japanese-char``                      | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on Japanese text. Text is tokenized into characters.                                                                        |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details on cl-tohoku repository <https://github.com/cl-tohoku/bert-japanese>`__).                                               |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``cl-tohoku/bert-base-japanese-char-whole-word-masking``   | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on Japanese text using Whole-Word-Masking. Text is tokenized into characters.                                               |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details on cl-tohoku repository <https://github.com/cl-tohoku/bert-japanese>`__).                                               |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``TurkuNLP/bert-base-finnish-cased-v1``                    | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on cased Finnish text.                                                                                                      |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details on turkunlp.org <http://turkunlp.org/FinBERT/>`__).                                                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``TurkuNLP/bert-base-finnish-uncased-v1``                  | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on uncased Finnish text.                                                                                                    |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details on turkunlp.org <http://turkunlp.org/FinBERT/>`__).                                                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``wietsedv/bert-base-dutch-cased``                         | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | Trained on cased Dutch text.                                                                                                        |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details on wietsedv repository <https://github.com/wietsedv/bertje/>`__).                                                       |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| GPT               | ``openai-gpt``                                             | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | OpenAI GPT English model                                                                                                            |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| GPT-2             | ``gpt2``                                                   | | 12-layer, 768-hidden, 12-heads, 117M parameters.                                                                                    |
-|                   |                                                            | | OpenAI GPT-2 English model                                                                                                          |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``gpt2-medium``                                            | | 24-layer, 1024-hidden, 16-heads, 345M parameters.                                                                                   |
-|                   |                                                            | | OpenAI's Medium-sized GPT-2 English model                                                                                           |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``gpt2-large``                                             | | 36-layer, 1280-hidden, 20-heads, 774M parameters.                                                                                   |
-|                   |                                                            | | OpenAI's Large-sized GPT-2 English model                                                                                            |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``gpt2-xl``                                                | | 48-layer, 1600-hidden, 25-heads, 1558M parameters.                                                                                  |
-|                   |                                                            | | OpenAI's XL-sized GPT-2 English model                                                                                               |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| Transformer-XL    | ``transfo-xl-wt103``                                       | | 18-layer, 1024-hidden, 16-heads, 257M parameters.                                                                                   |
-|                   |                                                            | | English model trained on wikitext-103                                                                                               |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| XLNet             | ``xlnet-base-cased``                                       | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
-|                   |                                                            | | XLNet English model                                                                                                                 |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``xlnet-large-cased``                                      | | 24-layer, 1024-hidden, 16-heads, 340M parameters.                                                                                   |
-|                   |                                                            | | XLNet Large English model                                                                                                           |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| XLM               | ``xlm-mlm-en-2048``                                        | | 12-layer, 2048-hidden, 16-heads                                                                                                     |
-|                   |                                                            | | XLM English model                                                                                                                   |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``xlm-mlm-ende-1024``                                      | | 6-layer, 1024-hidden, 8-heads                                                                                                       |
-|                   |                                                            | | XLM English-German model trained on the concatenation of English and German wikipedia                                               |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``xlm-mlm-enfr-1024``                                      | | 6-layer, 1024-hidden, 8-heads                                                                                                       |
-|                   |                                                            | | XLM English-French model trained on the concatenation of English and French wikipedia                                               |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``xlm-mlm-enro-1024``                                      | | 6-layer, 1024-hidden, 8-heads                                                                                                       |
-|                   |                                                            | | XLM English-Romanian Multi-language model                                                                                           |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``xlm-mlm-xnli15-1024``                                    | | 12-layer, 1024-hidden, 8-heads                                                                                                      |
-|                   |                                                            | | XLM Model pre-trained with MLM on the `15 XNLI languages <https://github.com/facebookresearch/XNLI>`__.                             |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``xlm-mlm-tlm-xnli15-1024``                                | | 12-layer, 1024-hidden, 8-heads                                                                                                      |
-|                   |                                                            | | XLM Model pre-trained with MLM + TLM on the `15 XNLI languages <https://github.com/facebookresearch/XNLI>`__.                       |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``xlm-clm-enfr-1024``                                      | | 6-layer, 1024-hidden, 8-heads                                                                                                       |
-|                   |                                                            | | XLM English-French model trained with CLM (Causal Language Modeling) on the concatenation of English and French wikipedia           |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``xlm-clm-ende-1024``                                      | | 6-layer, 1024-hidden, 8-heads                                                                                                       |
-|                   |                                                            | | XLM English-German model trained with CLM (Causal Language Modeling) on the concatenation of English and German wikipedia           |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``xlm-mlm-17-1280``                                        | | 16-layer, 1280-hidden, 16-heads                                                                                                     |
-|                   |                                                            | | XLM model trained with MLM (Masked Language Modeling) on 17 languages.                                                              |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``xlm-mlm-100-1280``                                       | | 16-layer, 1280-hidden, 16-heads                                                                                                     |
-|                   |                                                            | | XLM model trained with MLM (Masked Language Modeling) on 100 languages.                                                             |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| RoBERTa           | ``roberta-base``                                           | | 12-layer, 768-hidden, 12-heads, 125M parameters                                                                                     |
-|                   |                                                            | | RoBERTa using the BERT-base architecture                                                                                            |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/pytorch/fairseq/tree/master/examples/roberta>`__)                                                   |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``roberta-large``                                          | | 24-layer, 1024-hidden, 16-heads, 355M parameters                                                                                    |
-|                   |                                                            | | RoBERTa using the BERT-large architecture                                                                                           |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/pytorch/fairseq/tree/master/examples/roberta>`__)                                                   |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``roberta-large-mnli``                                     | | 24-layer, 1024-hidden, 16-heads, 355M parameters                                                                                    |
-|                   |                                                            | | ``roberta-large`` fine-tuned on `MNLI <http://www.nyu.edu/projects/bowman/multinli/>`__.                                            |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/pytorch/fairseq/tree/master/examples/roberta>`__)                                                   |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``distilroberta-base``                                     | | 6-layer, 768-hidden, 12-heads, 82M parameters                                                                                       |
-|                   |                                                            | | The DistilRoBERTa model distilled from the RoBERTa model `roberta-base` checkpoint.                                                 |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``roberta-base-openai-detector``                           | | 12-layer, 768-hidden, 12-heads, 125M parameters                                                                                     |
-|                   |                                                            | | ``roberta-base`` fine-tuned by OpenAI on the outputs of the 1.5B-parameter GPT-2 model.                                             |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/openai/gpt-2-output-dataset/tree/master/detector>`__)                                               |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``roberta-large-openai-detector``                          | | 24-layer, 1024-hidden, 16-heads, 355M parameters                                                                                    |
-|                   |                                                            | | ``roberta-large`` fine-tuned by OpenAI on the outputs of the 1.5B-parameter GPT-2 model.                                            |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/openai/gpt-2-output-dataset/tree/master/detector>`__)                                               |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| DistilBERT        | ``distilbert-base-uncased``                                | | 6-layer, 768-hidden, 12-heads, 66M parameters                                                                                       |
-|                   |                                                            | | The DistilBERT model distilled from the BERT model `bert-base-uncased` checkpoint                                                   |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``distilbert-base-uncased-distilled-squad``                | | 6-layer, 768-hidden, 12-heads, 66M parameters                                                                                       |
-|                   |                                                            | | The DistilBERT model distilled from the BERT model `bert-base-uncased` checkpoint, with an additional linear layer.                 |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``distilbert-base-cased``                                  | | 6-layer, 768-hidden, 12-heads, 65M parameters                                                                                       |
-|                   |                                                            | | The DistilBERT model distilled from the BERT model `bert-base-cased` checkpoint                                                     |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``distilbert-base-cased-distilled-squad``                  | | 6-layer, 768-hidden, 12-heads, 65M parameters                                                                                       |
-|                   |                                                            | | The DistilBERT model distilled from the BERT model `bert-base-cased` checkpoint, with an additional question answering layer.       |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``distilgpt2``                                             | | 6-layer, 768-hidden, 12-heads, 82M parameters                                                                                       |
-|                   |                                                            | | The DistilGPT2 model distilled from the GPT2 model `gpt2` checkpoint.                                                               |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``distilbert-base-german-cased``                           | | 6-layer, 768-hidden, 12-heads, 66M parameters                                                                                       |
-|                   |                                                            | | The German DistilBERT model distilled from the German DBMDZ BERT model `bert-base-german-dbmdz-cased` checkpoint.                   |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``distilbert-base-multilingual-cased``                     | | 6-layer, 768-hidden, 12-heads, 134M parameters                                                                                      |
-|                   |                                                            | | The multilingual DistilBERT model distilled from the Multilingual BERT model `bert-base-multilingual-cased` checkpoint.             |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| CTRL              | ``ctrl``                                                   | | 48-layer, 1280-hidden, 16-heads, 1.6B parameters                                                                                    |
-|                   |                                                            | | Salesforce's Large-sized CTRL English model                                                                                         |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| CamemBERT         | ``camembert-base``                                         | | 12-layer, 768-hidden, 12-heads, 110M parameters                                                                                     |
-|                   |                                                            | | CamemBERT using the BERT-base architecture                                                                                          |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/pytorch/fairseq/tree/master/examples/camembert>`__)                                                 |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| ALBERT            | ``albert-base-v1``                                         | | 12 repeating layers, 128 embedding, 768-hidden, 12-heads, 11M parameters                                                            |
-|                   |                                                            | | ALBERT base model                                                                                                                   |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``albert-large-v1``                                        | | 24 repeating layers, 128 embedding, 1024-hidden, 16-heads, 17M parameters                                                           |
-|                   |                                                            | | ALBERT large model                                                                                                                  |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``albert-xlarge-v1``                                       | | 24 repeating layers, 128 embedding, 2048-hidden, 16-heads, 58M parameters                                                           |
-|                   |                                                            | | ALBERT xlarge model                                                                                                                 |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``albert-xxlarge-v1``                                      | | 12 repeating layer, 128 embedding, 4096-hidden, 64-heads, 223M parameters                                                           |
-|                   |                                                            | | ALBERT xxlarge model                                                                                                                |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``albert-base-v2``                                         | | 12 repeating layers, 128 embedding, 768-hidden, 12-heads, 11M parameters                                                            |
-|                   |                                                            | | ALBERT base model with no dropout, additional training data and longer training                                                     |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``albert-large-v2``                                        | | 24 repeating layers, 128 embedding, 1024-hidden, 16-heads, 17M parameters                                                           |
-|                   |                                                            | | ALBERT large model with no dropout, additional training data and longer training                                                    |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``albert-xlarge-v2``                                       | | 24 repeating layers, 128 embedding, 2048-hidden, 16-heads, 58M parameters                                                           |
-|                   |                                                            | | ALBERT xlarge model with no dropout, additional training data and longer training                                                   |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``albert-xxlarge-v2``                                      | | 12 repeating layer, 128 embedding, 4096-hidden, 64-heads, 223M parameters                                                           |
-|                   |                                                            | | ALBERT xxlarge model with no dropout, additional training data and longer training                                                  |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| T5                | ``t5-small``                                               | | ~60M parameters with 6-layers, 512-hidden-state, 2048 feed-forward hidden-state, 8-heads,                                           |
-|                   |                                                            | | Trained on English text: the Colossal Clean Crawled Corpus (C4)                                                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``t5-base``                                                | | ~220M parameters with 12-layers, 768-hidden-state, 3072 feed-forward hidden-state, 12-heads,                                        |
-|                   |                                                            | | Trained on English text: the Colossal Clean Crawled Corpus (C4)                                                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``t5-large``                                               | | ~770M parameters with 24-layers, 1024-hidden-state, 4096 feed-forward hidden-state, 16-heads,                                       |
-|                   |                                                            | | Trained on English text: the Colossal Clean Crawled Corpus (C4)                                                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``t5-3B``                                                  | | ~2.8B parameters with 24-layers, 1024-hidden-state, 16384 feed-forward hidden-state, 32-heads,                                      |
-|                   |                                                            | | Trained on English text: the Colossal Clean Crawled Corpus (C4)                                                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``t5-11B``                                                 | | ~11B parameters with 24-layers, 1024-hidden-state, 65536 feed-forward hidden-state, 128-heads,                                      |
-|                   |                                                            | | Trained on English text: the Colossal Clean Crawled Corpus (C4)                                                                     |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| XLM-RoBERTa       | ``xlm-roberta-base``                                       | | ~125M parameters with 12-layers, 768-hidden-state, 3072 feed-forward hidden-state, 8-heads,                                         |
-|                   |                                                            | | Trained on on 2.5 TB of newly created clean CommonCrawl data in 100 languages                                                       |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``xlm-roberta-large``                                      | | ~355M parameters with 24-layers, 1027-hidden-state, 4096 feed-forward hidden-state, 16-heads,                                       |
-|                   |                                                            | | Trained on 2.5 TB of newly created clean CommonCrawl data in 100 languages                                                          |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| FlauBERT          | ``flaubert/flaubert_small_cased``                          | | 6-layer, 512-hidden, 8-heads, 54M parameters                                                                                        |
-|                   |                                                            | | FlauBERT small architecture                                                                                                         |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/getalp/Flaubert>`__)                                                                                |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``flaubert/flaubert_base_uncased``                         | | 12-layer, 768-hidden, 12-heads, 137M parameters                                                                                     |
-|                   |                                                            | | FlauBERT base architecture with uncased vocabulary                                                                                  |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/getalp/Flaubert>`__)                                                                                |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``flaubert/flaubert_base_cased``                           | | 12-layer, 768-hidden, 12-heads, 138M parameters                                                                                     |
-|                   |                                                            | | FlauBERT base architecture with cased vocabulary                                                                                    |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/getalp/Flaubert>`__)                                                                                |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``flaubert/flaubert_large_cased``                          | | 24-layer, 1024-hidden, 16-heads, 373M parameters                                                                                    |
-|                   |                                                            | | FlauBERT large architecture                                                                                                         |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/getalp/Flaubert>`__)                                                                                |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| Bart              | ``facebook/bart-large``                                    | | 24-layer, 1024-hidden, 16-heads, 406M parameters                                                                                    |
-|                   |                                                            |                                                                                                                                       |
-|                   |                                                            | (see `details <https://github.com/pytorch/fairseq/tree/master/examples/bart>`_)                                                       |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``facebook/bart-base``                                     | | 12-layer, 768-hidden, 16-heads, 139M parameters                                                                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``facebook/bart-large-mnli``                               | | Adds a 2 layer classification head with 1 million parameters                                                                        |
-|                   |                                                            | | bart-large base architecture with a classification head, finetuned on MNLI                                                          |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``facebook/bart-large-cnn``                                | | 12-layer, 1024-hidden, 16-heads, 406M parameters       (same as base)                                                               |
-|                   |                                                            | | bart-large base architecture finetuned on cnn summarization task                                                                    |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``facebook/mbart-large-en-ro``                             | | 12-layer, 1024-hidden, 16-heads, 880M parameters                                                                                    |
-|                   |                                                            | | bart-large architecture pretrained on cc25 multilingual data , finetuned on WMT english romanian translation.                       |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| DialoGPT          | ``DialoGPT-small``                                         | | 12-layer, 768-hidden, 12-heads, 124M parameters                                                                                     |
-|                   |                                                            | | Trained on English text: 147M conversation-like exchanges extracted from Reddit.                                                    |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``DialoGPT-medium``                                        | | 24-layer, 1024-hidden, 16-heads, 355M parameters                                                                                    |
-|                   |                                                            | | Trained on English text: 147M conversation-like exchanges extracted from Reddit.                                                    |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``DialoGPT-large``                                         | | 36-layer, 1280-hidden, 20-heads, 774M parameters                                                                                    |
-|                   |                                                            | | Trained on English text: 147M conversation-like exchanges extracted from Reddit.                                                    |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| Reformer          | ``reformer-enwik8``                                        | | 12-layer, 1024-hidden, 8-heads, 149M parameters                                                                                     |
-|                   |                                                            | | Trained on English Wikipedia data - enwik8.                                                                                         |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``reformer-crime-and-punishment``                          | | 6-layer, 256-hidden, 2-heads, 3M parameters                                                                                         |
-|                   |                                                            | | Trained on English text: Crime and Punishment novel by Fyodor Dostoyevsky.                                                          |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| MarianMT          | ``Helsinki-NLP/opus-mt-{src}-{tgt}``                       | | 12-layer, 512-hidden, 8-heads, ~74M parameter Machine translation models. Parameter counts vary depending on vocab size.            |
-|                   |                                                            | | (see `model list <https://huggingface.co/Helsinki-NLP>`_)                                                                           |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| Pegasus           | ``google/pegasus-{dataset}``                               | | 16-layer, 1024-hidden, 16-heads, ~568M parameter, 2.2 GB for summary. `model list <https://huggingface.co/models?search=pegasus>`__ |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-| Longformer        | ``allenai/longformer-base-4096``                           | | 12-layer, 768-hidden, 12-heads, ~149M parameters                                                                                    |
-|                   |                                                            | | Starting from RoBERTa-base checkpoint, trained on documents of max length 4,096                                                     |
-|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
-|                   | ``allenai/longformer-large-4096``                          | | 24-layer, 1024-hidden, 16-heads, ~435M parameters                                                                                   |
-|                   |                                                            | | Starting from RoBERTa-large checkpoint, trained on documents of max length 4,096                                                    |
-+-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| Architecture       | Shortcut name                                              | Details of the model                                                                                                                  |
++====================+============================================================+=======================================================================================================================================+
+| BERT               | ``bert-base-uncased``                                      | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on lower-cased English text.                                                                                                |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-large-uncased``                                     | | 24-layer, 1024-hidden, 16-heads, 340M parameters.                                                                                   |
+|                    |                                                            | | Trained on lower-cased English text.                                                                                                |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-base-cased``                                        | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on cased English text.                                                                                                      |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-large-cased``                                       | | 24-layer, 1024-hidden, 16-heads, 340M parameters.                                                                                   |
+|                    |                                                            | | Trained on cased English text.                                                                                                      |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-base-multilingual-uncased``                         | | (Original, not recommended) 12-layer, 768-hidden, 12-heads, 110M parameters.                                                        |
+|                    |                                                            | | Trained on lower-cased text in the top 102 languages with the largest Wikipedias                                                    |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/google-research/bert/blob/master/multilingual.md>`__).                                              |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-base-multilingual-cased``                           | | (New, **recommended**) 12-layer, 768-hidden, 12-heads, 110M parameters.                                                             |
+|                    |                                                            | | Trained on cased text in the top 104 languages with the largest Wikipedias                                                          |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/google-research/bert/blob/master/multilingual.md>`__).                                              |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-base-chinese``                                      | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on cased Chinese Simplified and Traditional text.                                                                           |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-base-german-cased``                                 | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on cased German text by Deepset.ai                                                                                          |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details on deepset.ai website <https://deepset.ai/german-bert>`__).                                                             |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-large-uncased-whole-word-masking``                  | | 24-layer, 1024-hidden, 16-heads, 340M parameters.                                                                                   |
+|                    |                                                            | | Trained on lower-cased English text using Whole-Word-Masking                                                                        |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/google-research/bert/#bert>`__).                                                                    |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-large-cased-whole-word-masking``                    | | 24-layer, 1024-hidden, 16-heads, 340M parameters.                                                                                   |
+|                    |                                                            | | Trained on cased English text using Whole-Word-Masking                                                                              |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/google-research/bert/#bert>`__).                                                                    |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-large-uncased-whole-word-masking-finetuned-squad``  | | 24-layer, 1024-hidden, 16-heads, 340M parameters.                                                                                   |
+|                    |                                                            | | The ``bert-large-uncased-whole-word-masking`` model fine-tuned on SQuAD                                                             |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see details of fine-tuning in the `example section <https://github.com/huggingface/transformers/tree/master/examples>`__).           |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-large-cased-whole-word-masking-finetuned-squad``    | | 24-layer, 1024-hidden, 16-heads, 340M parameters                                                                                    |
+|                    |                                                            | | The ``bert-large-cased-whole-word-masking`` model fine-tuned on SQuAD                                                               |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details of fine-tuning in the example section <https://huggingface.co/transformers/examples.html>`__)                           |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-base-cased-finetuned-mrpc``                         | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | The ``bert-base-cased`` model fine-tuned on MRPC                                                                                    |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details of fine-tuning in the example section <https://huggingface.co/transformers/examples.html>`__)                           |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-base-german-dbmdz-cased``                           | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on cased German text by DBMDZ                                                                                               |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details on dbmdz repository <https://github.com/dbmdz/german-bert>`__).                                                         |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``bert-base-german-dbmdz-uncased``                         | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on uncased German text by DBMDZ                                                                                             |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details on dbmdz repository <https://github.com/dbmdz/german-bert>`__).                                                         |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``cl-tohoku/bert-base-japanese``                           | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on Japanese text. Text is tokenized with MeCab and WordPiece and this requires some extra dependencies,                     |
+|                    |                                                            | | `fugashi <https://github.com/polm/fugashi>`__ which is a wrapper around `MeCab <https://taku910.github.io/mecab/>`__.               |
+|                    |                                                            | | Use ``pip install transformers["ja"]`` (or ``pip install -e .["ja"]`` if you install from source) to install them.                  |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details on cl-tohoku repository <https://github.com/cl-tohoku/bert-japanese>`__).                                               |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``cl-tohoku/bert-base-japanese-whole-word-masking``        | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on Japanese text. Text is tokenized with MeCab and WordPiece and this requires some extra dependencies,                     |
+|                    |                                                            | | `fugashi <https://github.com/polm/fugashi>`__ which is a wrapper around `MeCab <https://taku910.github.io/mecab/>`__.               |
+|                    |                                                            | | Use ``pip install transformers["ja"]`` (or ``pip install -e .["ja"]`` if you install from source) to install them.                  |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details on cl-tohoku repository <https://github.com/cl-tohoku/bert-japanese>`__).                                               |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``cl-tohoku/bert-base-japanese-char``                      | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on Japanese text. Text is tokenized into characters.                                                                        |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details on cl-tohoku repository <https://github.com/cl-tohoku/bert-japanese>`__).                                               |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``cl-tohoku/bert-base-japanese-char-whole-word-masking``   | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on Japanese text using Whole-Word-Masking. Text is tokenized into characters.                                               |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details on cl-tohoku repository <https://github.com/cl-tohoku/bert-japanese>`__).                                               |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``TurkuNLP/bert-base-finnish-cased-v1``                    | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on cased Finnish text.                                                                                                      |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details on turkunlp.org <http://turkunlp.org/FinBERT/>`__).                                                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``TurkuNLP/bert-base-finnish-uncased-v1``                  | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on uncased Finnish text.                                                                                                    |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details on turkunlp.org <http://turkunlp.org/FinBERT/>`__).                                                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``wietsedv/bert-base-dutch-cased``                         | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | Trained on cased Dutch text.                                                                                                        |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details on wietsedv repository <https://github.com/wietsedv/bertje/>`__).                                                       |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| GPT                | ``openai-gpt``                                             | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | OpenAI GPT English model                                                                                                            |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| GPT-2              | ``gpt2``                                                   | | 12-layer, 768-hidden, 12-heads, 117M parameters.                                                                                    |
+|                    |                                                            | | OpenAI GPT-2 English model                                                                                                          |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``gpt2-medium``                                            | | 24-layer, 1024-hidden, 16-heads, 345M parameters.                                                                                   |
+|                    |                                                            | | OpenAI's Medium-sized GPT-2 English model                                                                                           |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``gpt2-large``                                             | | 36-layer, 1280-hidden, 20-heads, 774M parameters.                                                                                   |
+|                    |                                                            | | OpenAI's Large-sized GPT-2 English model                                                                                            |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``gpt2-xl``                                                | | 48-layer, 1600-hidden, 25-heads, 1558M parameters.                                                                                  |
+|                    |                                                            | | OpenAI's XL-sized GPT-2 English model                                                                                               |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| Transformer-XL     | ``transfo-xl-wt103``                                       | | 18-layer, 1024-hidden, 16-heads, 257M parameters.                                                                                   |
+|                    |                                                            | | English model trained on wikitext-103                                                                                               |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| XLNet              | ``xlnet-base-cased``                                       | | 12-layer, 768-hidden, 12-heads, 110M parameters.                                                                                    |
+|                    |                                                            | | XLNet English model                                                                                                                 |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``xlnet-large-cased``                                      | | 24-layer, 1024-hidden, 16-heads, 340M parameters.                                                                                   |
+|                    |                                                            | | XLNet Large English model                                                                                                           |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| XLM                | ``xlm-mlm-en-2048``                                        | | 12-layer, 2048-hidden, 16-heads                                                                                                     |
+|                    |                                                            | | XLM English model                                                                                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``xlm-mlm-ende-1024``                                      | | 6-layer, 1024-hidden, 8-heads                                                                                                       |
+|                    |                                                            | | XLM English-German model trained on the concatenation of English and German wikipedia                                               |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``xlm-mlm-enfr-1024``                                      | | 6-layer, 1024-hidden, 8-heads                                                                                                       |
+|                    |                                                            | | XLM English-French model trained on the concatenation of English and French wikipedia                                               |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``xlm-mlm-enro-1024``                                      | | 6-layer, 1024-hidden, 8-heads                                                                                                       |
+|                    |                                                            | | XLM English-Romanian Multi-language model                                                                                           |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``xlm-mlm-xnli15-1024``                                    | | 12-layer, 1024-hidden, 8-heads                                                                                                      |
+|                    |                                                            | | XLM Model pre-trained with MLM on the `15 XNLI languages <https://github.com/facebookresearch/XNLI>`__.                             |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``xlm-mlm-tlm-xnli15-1024``                                | | 12-layer, 1024-hidden, 8-heads                                                                                                      |
+|                    |                                                            | | XLM Model pre-trained with MLM + TLM on the `15 XNLI languages <https://github.com/facebookresearch/XNLI>`__.                       |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``xlm-clm-enfr-1024``                                      | | 6-layer, 1024-hidden, 8-heads                                                                                                       |
+|                    |                                                            | | XLM English-French model trained with CLM (Causal Language Modeling) on the concatenation of English and French wikipedia           |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``xlm-clm-ende-1024``                                      | | 6-layer, 1024-hidden, 8-heads                                                                                                       |
+|                    |                                                            | | XLM English-German model trained with CLM (Causal Language Modeling) on the concatenation of English and German wikipedia           |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``xlm-mlm-17-1280``                                        | | 16-layer, 1280-hidden, 16-heads                                                                                                     |
+|                    |                                                            | | XLM model trained with MLM (Masked Language Modeling) on 17 languages.                                                              |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``xlm-mlm-100-1280``                                       | | 16-layer, 1280-hidden, 16-heads                                                                                                     |
+|                    |                                                            | | XLM model trained with MLM (Masked Language Modeling) on 100 languages.                                                             |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| RoBERTa            | ``roberta-base``                                           | | 12-layer, 768-hidden, 12-heads, 125M parameters                                                                                     |
+|                    |                                                            | | RoBERTa using the BERT-base architecture                                                                                            |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/pytorch/fairseq/tree/master/examples/roberta>`__)                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``roberta-large``                                          | | 24-layer, 1024-hidden, 16-heads, 355M parameters                                                                                    |
+|                    |                                                            | | RoBERTa using the BERT-large architecture                                                                                           |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/pytorch/fairseq/tree/master/examples/roberta>`__)                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``roberta-large-mnli``                                     | | 24-layer, 1024-hidden, 16-heads, 355M parameters                                                                                    |
+|                    |                                                            | | ``roberta-large`` fine-tuned on `MNLI <http://www.nyu.edu/projects/bowman/multinli/>`__.                                            |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/pytorch/fairseq/tree/master/examples/roberta>`__)                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``distilroberta-base``                                     | | 6-layer, 768-hidden, 12-heads, 82M parameters                                                                                       |
+|                    |                                                            | | The DistilRoBERTa model distilled from the RoBERTa model `roberta-base` checkpoint.                                                 |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``roberta-base-openai-detector``                           | | 12-layer, 768-hidden, 12-heads, 125M parameters                                                                                     |
+|                    |                                                            | | ``roberta-base`` fine-tuned by OpenAI on the outputs of the 1.5B-parameter GPT-2 model.                                             |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/openai/gpt-2-output-dataset/tree/master/detector>`__)                                               |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``roberta-large-openai-detector``                          | | 24-layer, 1024-hidden, 16-heads, 355M parameters                                                                                    |
+|                    |                                                            | | ``roberta-large`` fine-tuned by OpenAI on the outputs of the 1.5B-parameter GPT-2 model.                                            |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/openai/gpt-2-output-dataset/tree/master/detector>`__)                                               |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| DistilBERT         | ``distilbert-base-uncased``                                | | 6-layer, 768-hidden, 12-heads, 66M parameters                                                                                       |
+|                    |                                                            | | The DistilBERT model distilled from the BERT model `bert-base-uncased` checkpoint                                                   |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``distilbert-base-uncased-distilled-squad``                | | 6-layer, 768-hidden, 12-heads, 66M parameters                                                                                       |
+|                    |                                                            | | The DistilBERT model distilled from the BERT model `bert-base-uncased` checkpoint, with an additional linear layer.                 |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``distilbert-base-cased``                                  | | 6-layer, 768-hidden, 12-heads, 65M parameters                                                                                       |
+|                    |                                                            | | The DistilBERT model distilled from the BERT model `bert-base-cased` checkpoint                                                     |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``distilbert-base-cased-distilled-squad``                  | | 6-layer, 768-hidden, 12-heads, 65M parameters                                                                                       |
+|                    |                                                            | | The DistilBERT model distilled from the BERT model `bert-base-cased` checkpoint, with an additional question answering layer.       |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``distilgpt2``                                             | | 6-layer, 768-hidden, 12-heads, 82M parameters                                                                                       |
+|                    |                                                            | | The DistilGPT2 model distilled from the GPT2 model `gpt2` checkpoint.                                                               |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``distilbert-base-german-cased``                           | | 6-layer, 768-hidden, 12-heads, 66M parameters                                                                                       |
+|                    |                                                            | | The German DistilBERT model distilled from the German DBMDZ BERT model `bert-base-german-dbmdz-cased` checkpoint.                   |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``distilbert-base-multilingual-cased``                     | | 6-layer, 768-hidden, 12-heads, 134M parameters                                                                                      |
+|                    |                                                            | | The multilingual DistilBERT model distilled from the Multilingual BERT model `bert-base-multilingual-cased` checkpoint.             |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| CTRL               | ``ctrl``                                                   | | 48-layer, 1280-hidden, 16-heads, 1.6B parameters                                                                                    |
+|                    |                                                            | | Salesforce's Large-sized CTRL English model                                                                                         |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| CamemBERT          | ``camembert-base``                                         | | 12-layer, 768-hidden, 12-heads, 110M parameters                                                                                     |
+|                    |                                                            | | CamemBERT using the BERT-base architecture                                                                                          |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/pytorch/fairseq/tree/master/examples/camembert>`__)                                                 |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| ALBERT             | ``albert-base-v1``                                         | | 12 repeating layers, 128 embedding, 768-hidden, 12-heads, 11M parameters                                                            |
+|                    |                                                            | | ALBERT base model                                                                                                                   |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``albert-large-v1``                                        | | 24 repeating layers, 128 embedding, 1024-hidden, 16-heads, 17M parameters                                                           |
+|                    |                                                            | | ALBERT large model                                                                                                                  |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``albert-xlarge-v1``                                       | | 24 repeating layers, 128 embedding, 2048-hidden, 16-heads, 58M parameters                                                           |
+|                    |                                                            | | ALBERT xlarge model                                                                                                                 |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``albert-xxlarge-v1``                                      | | 12 repeating layer, 128 embedding, 4096-hidden, 64-heads, 223M parameters                                                           |
+|                    |                                                            | | ALBERT xxlarge model                                                                                                                |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``albert-base-v2``                                         | | 12 repeating layers, 128 embedding, 768-hidden, 12-heads, 11M parameters                                                            |
+|                    |                                                            | | ALBERT base model with no dropout, additional training data and longer training                                                     |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``albert-large-v2``                                        | | 24 repeating layers, 128 embedding, 1024-hidden, 16-heads, 17M parameters                                                           |
+|                    |                                                            | | ALBERT large model with no dropout, additional training data and longer training                                                    |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``albert-xlarge-v2``                                       | | 24 repeating layers, 128 embedding, 2048-hidden, 16-heads, 58M parameters                                                           |
+|                    |                                                            | | ALBERT xlarge model with no dropout, additional training data and longer training                                                   |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``albert-xxlarge-v2``                                      | | 12 repeating layer, 128 embedding, 4096-hidden, 64-heads, 223M parameters                                                           |
+|                    |                                                            | | ALBERT xxlarge model with no dropout, additional training data and longer training                                                  |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/google-research/ALBERT>`__)                                                                         |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| T5                 | ``t5-small``                                               | | ~60M parameters with 6-layers, 512-hidden-state, 2048 feed-forward hidden-state, 8-heads,                                           |
+|                    |                                                            | | Trained on English text: the Colossal Clean Crawled Corpus (C4)                                                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``t5-base``                                                | | ~220M parameters with 12-layers, 768-hidden-state, 3072 feed-forward hidden-state, 12-heads,                                        |
+|                    |                                                            | | Trained on English text: the Colossal Clean Crawled Corpus (C4)                                                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``t5-large``                                               | | ~770M parameters with 24-layers, 1024-hidden-state, 4096 feed-forward hidden-state, 16-heads,                                       |
+|                    |                                                            | | Trained on English text: the Colossal Clean Crawled Corpus (C4)                                                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``t5-3B``                                                  | | ~2.8B parameters with 24-layers, 1024-hidden-state, 16384 feed-forward hidden-state, 32-heads,                                      |
+|                    |                                                            | | Trained on English text: the Colossal Clean Crawled Corpus (C4)                                                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``t5-11B``                                                 | | ~11B parameters with 24-layers, 1024-hidden-state, 65536 feed-forward hidden-state, 128-heads,                                      |
+|                    |                                                            | | Trained on English text: the Colossal Clean Crawled Corpus (C4)                                                                     |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| XLM-RoBERTa        | ``xlm-roberta-base``                                       | | ~125M parameters with 12-layers, 768-hidden-state, 3072 feed-forward hidden-state, 8-heads,                                         |
+|                    |                                                            | | Trained on on 2.5 TB of newly created clean CommonCrawl data in 100 languages                                                       |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``xlm-roberta-large``                                      | | ~355M parameters with 24-layers, 1027-hidden-state, 4096 feed-forward hidden-state, 16-heads,                                       |
+|                    |                                                            | | Trained on 2.5 TB of newly created clean CommonCrawl data in 100 languages                                                          |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| FlauBERT           | ``flaubert/flaubert_small_cased``                          | | 6-layer, 512-hidden, 8-heads, 54M parameters                                                                                        |
+|                    |                                                            | | FlauBERT small architecture                                                                                                         |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/getalp/Flaubert>`__)                                                                                |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``flaubert/flaubert_base_uncased``                         | | 12-layer, 768-hidden, 12-heads, 137M parameters                                                                                     |
+|                    |                                                            | | FlauBERT base architecture with uncased vocabulary                                                                                  |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/getalp/Flaubert>`__)                                                                                |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``flaubert/flaubert_base_cased``                           | | 12-layer, 768-hidden, 12-heads, 138M parameters                                                                                     |
+|                    |                                                            | | FlauBERT base architecture with cased vocabulary                                                                                    |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/getalp/Flaubert>`__)                                                                                |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``flaubert/flaubert_large_cased``                          | | 24-layer, 1024-hidden, 16-heads, 373M parameters                                                                                    |
+|                    |                                                            | | FlauBERT large architecture                                                                                                         |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/getalp/Flaubert>`__)                                                                                |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| Bart               | ``facebook/bart-large``                                    | | 24-layer, 1024-hidden, 16-heads, 406M parameters                                                                                    |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/pytorch/fairseq/tree/master/examples/bart>`_)                                                       |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``facebook/bart-base``                                     | | 12-layer, 768-hidden, 16-heads, 139M parameters                                                                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``facebook/bart-large-mnli``                               | | Adds a 2 layer classification head with 1 million parameters                                                                        |
+|                    |                                                            | | bart-large base architecture with a classification head, finetuned on MNLI                                                          |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``facebook/bart-large-cnn``                                | | 12-layer, 1024-hidden, 16-heads, 406M parameters       (same as base)                                                               |
+|                    |                                                            | | bart-large base architecture finetuned on cnn summarization task                                                                    |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| DialoGPT           | ``DialoGPT-small``                                         | | 12-layer, 768-hidden, 12-heads, 124M parameters                                                                                     |
+|                    |                                                            | | Trained on English text: 147M conversation-like exchanges extracted from Reddit.                                                    |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``DialoGPT-medium``                                        | | 24-layer, 1024-hidden, 16-heads, 355M parameters                                                                                    |
+|                    |                                                            | | Trained on English text: 147M conversation-like exchanges extracted from Reddit.                                                    |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``DialoGPT-large``                                         | | 36-layer, 1280-hidden, 20-heads, 774M parameters                                                                                    |
+|                    |                                                            | | Trained on English text: 147M conversation-like exchanges extracted from Reddit.                                                    |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| Reformer           | ``reformer-enwik8``                                        | | 12-layer, 1024-hidden, 8-heads, 149M parameters                                                                                     |
+|                    |                                                            | | Trained on English Wikipedia data - enwik8.                                                                                         |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``reformer-crime-and-punishment``                          | | 6-layer, 256-hidden, 2-heads, 3M parameters                                                                                         |
+|                    |                                                            | | Trained on English text: Crime and Punishment novel by Fyodor Dostoyevsky.                                                          |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| MarianMT           | ``Helsinki-NLP/opus-mt-{src}-{tgt}``                       | | 12-layer, 512-hidden, 8-heads, ~74M parameter Machine translation models. Parameter counts vary depending on vocab size.            |
+|                    |                                                            | | (see `model list <https://huggingface.co/Helsinki-NLP>`_)                                                                           |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| Pegasus            | ``google/pegasus-{dataset}``                               | | 16-layer, 1024-hidden, 16-heads, ~568M parameter, 2.2 GB for summary. `model list <https://huggingface.co/models?search=pegasus>`__ |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| Longformer         | ``allenai/longformer-base-4096``                           | | 12-layer, 768-hidden, 12-heads, ~149M parameters                                                                                    |
+|                    |                                                            | | Starting from RoBERTa-base checkpoint, trained on documents of max length 4,096                                                     |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``allenai/longformer-large-4096``                          | | 24-layer, 1024-hidden, 16-heads, ~435M parameters                                                                                   |
+|                    |                                                            | | Starting from RoBERTa-large checkpoint, trained on documents of max length 4,096                                                    |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| MBart              | ``facebook/mbart-large-cc25``                              | | 24-layer, 1024-hidden, 16-heads, 610M parameters                                                                                    |
+|                    |                                                            | | mBART (bart-large architecture) model trained on 25 languages' monolingual corpus                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``facebook/mbart-large-en-ro``                             | | 24-layer, 1024-hidden, 16-heads, 610M parameters                                                                                    |
+|                    |                                                            | | mbart-large-cc25 model finetuned on WMT english romanian translation.                                                               |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| Lxmert             | ``lxmert-base-uncased``                                    | | 9-language layers, 9-relationship layers, and 12-cross-modality layers                                                              |
+|                    |                                                            | | 768-hidden, 12-heads (for each layer) ~ 228M parameters                                                                             |
+|                    |                                                            | | Starting from lxmert-base checkpoint, trained on over 9 million image-text couplets from COCO, VisualGenome, GQA, VQA               |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| Funnel Transformer | ``funnel-transformer/small``                               | | 14 layers: 3 blocks of 4 layers then 2 layers decoder, 768-hidden, 12-heads, 130M parameters                                        |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/laiguokun/Funnel-Transformer>`__)                                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``funnel-transformer/small-base``                          | | 12 layers: 3 blocks of 4 layers (no decoder), 768-hidden, 12-heads, 115M parameters                                                 |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/laiguokun/Funnel-Transformer>`__)                                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``funnel-transformer/medium``                              | | 14 layers: 3 blocks 6, 3x2, 3x2 layers then 2 layers decoder, 768-hidden, 12-heads, 130M parameters                                 |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/laiguokun/Funnel-Transformer>`__)                                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``funnel-transformer/medium-base``                         | | 12 layers: 3 blocks 6, 3x2, 3x2 layers(no decoder), 768-hidden, 12-heads, 115M parameters                                           |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/laiguokun/Funnel-Transformer>`__)                                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``funnel-transformer/intermediate``                        | | 20 layers: 3 blocks of 6 layers then 2 layers decoder, 768-hidden, 12-heads, 177M parameters                                        |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/laiguokun/Funnel-Transformer>`__)                                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``funnel-transformer/intermediate-base``                   | | 18 layers: 3 blocks of 6 layers (no decoder), 768-hidden, 12-heads, 161M parameters                                                 |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/laiguokun/Funnel-Transformer>`__)                                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``funnel-transformer/large``                               | | 26 layers: 3 blocks of 8 layers then 2 layers decoder, 1024-hidden, 12-heads, 386M parameters                                       |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/laiguokun/Funnel-Transformer>`__)                                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``funnel-transformer/large-base``                          | | 24 layers: 3 blocks of 8 layers (no decoder), 1024-hidden, 12-heads, 358M parameters                                                |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/laiguokun/Funnel-Transformer>`__)                                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``funnel-transformer/xlarge``                              | | 32 layers: 3 blocks of 10 layers then 2 layers decoder, 1024-hidden, 12-heads, 468M parameters                                      |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/laiguokun/Funnel-Transformer>`__)                                                                   |
+|                    +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                    | ``funnel-transformer/xlarge-base``                         | | 30 layers: 3 blocks of 10 layers (no decoder), 1024-hidden, 12-heads, 440M parameters                                               |
+|                    |                                                            |                                                                                                                                       |
+|                    |                                                            | (see `details <https://github.com/laiguokun/Funnel-Transformer>`__)                                                                   |
++--------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+

docs/source/quicktour.rst

@@ -214,7 +214,7 @@ Using the model
 
 Once your input has been preprocessed by the tokenizer, you can send it directly to the model. As we mentioned, it will
 contain all the relevant information the model needs. If you're using a TensorFlow model, you can pass the
-dictionary keys directly to tensor, for a PyTorch model, you need to unpack the dictionary by adding :obj:`**`.
+dictionary keys directly to tensors, for a PyTorch model, you need to unpack the dictionary by adding :obj:`**`.
 
 .. code-block::
 

docs/source/serialization.rst

@@ -52,15 +52,17 @@ Below are some of the operators which can be enabled to speed up inference throu
 * Skip connection LayerNormalization fusing
 * FastGeLU approximation
 
+Some of the optimizations performed by ONNX runtime can be hardware specific and thus lead to different performances
+if used on another machine with a different hardware configuration than the one used for exporting the model.
+For this reason, when using ``convert_graph_to_onnx.py`` optimizations are not enabled,
+ensuring the model can be easily exported to various hardware.
+Optimizations can then be enabled when loading the model through ONNX runtime for inference.
 
-Fortunately, you can let ONNXRuntime find all the possible optimized operators for you. Simply add ``--optimize``
-when exporting your model through ``convert_graph_to_onnx.py``.
 
-Example:
-
-.. code-block:: bash
-
-    python convert_graph_to_onnx.py --framework <pt, tf> --model bert-base-cased --optimize bert-base-cased.onnx
+.. note::
+    When quantization is enabled (see below), ``convert_graph_to_onnx.py`` script will enable optimizations on the model
+    because quantization would modify the underlying graph making it impossible for ONNX runtime to do the optimizations
+    afterwards.
 
 .. note::
     For more information about the optimizations enabled by ONNXRuntime, please have a look at the (`ONNXRuntime Github <https://github.com/microsoft/onnxruntime/tree/master/onnxruntime/python/tools/transformers>`_)
@@ -112,8 +114,6 @@ Example of quantized BERT model export:
     above command will contain the original ONNX model storing `float32` weights.
     The second one, with ``-quantized`` suffix, will hold the quantized parameters.
 
-.. note::
-    The quantization export gives the best performances when used in combination with ``--optimize``.
 
 TorchScript
 =======================================
@@ -130,13 +130,12 @@ Pytorch's two modules `JIT and TRACE <https://pytorch.org/docs/stable/jit.html>`
 their model to be re-used in other programs, such as efficiency-oriented C++ programs.
 
 We have provided an interface that allows the export of 🤗 Transformers models to TorchScript so that they can
-be reused in a different environment than a Pytorch-based python program. Here we explain how to use our models so that
-they can be exported, and what to be mindful of when using these models with TorchScript.
+be reused in a different environment than a Pytorch-based python program. Here we explain how to export and use our models using TorchScript.
 
-Exporting a model needs two things:
+Exporting a model requires two things:
 
-* dummy inputs to execute a model forward pass.
-* the model needs to be instantiated with the ``torchscript`` flag.
+* a forward pass with dummy inputs.
+* model instantiation with the ``torchscript`` flag.
 
 These necessities imply several things developers should be careful about. These are detailed below.
 
@@ -147,8 +146,8 @@ Implications
 TorchScript flag and tied weights
 ------------------------------------------------
 This flag is necessary because most of the language models in this repository have tied weights between their
-``Embedding`` layer and their ``Decoding`` layer. TorchScript does not allow the export of models that have tied weights,
-it is therefore necessary to untie the weights beforehand.
+``Embedding`` layer and their ``Decoding`` layer. TorchScript does not allow the export of models that have tied weights, therefore
+it is necessary to untie and clone the weights beforehand.
 
 This implies that models instantiated with the ``torchscript`` flag have their ``Embedding`` layer and ``Decoding`` layer
 separate, which means that they should not be trained down the line. Training would de-synchronize the two layers,
@@ -181,7 +180,7 @@ when exporting varying sequence-length models.
 Using TorchScript in Python
 -------------------------------------------------
 
-Below are examples of using the Python to save, load models as well as how to use the trace for inference.
+Below is an example, showing how to save, load models as well as how to use the trace for inference.
 
 Saving a model
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -237,10 +236,10 @@ We are re-using the previously initialised ``dummy_input``.
 
 .. code-block:: python
 
-    loaded_model = torch.jit.load("traced_model.pt")
+    loaded_model = torch.jit.load("traced_bert.pt")
     loaded_model.eval()
 
-    all_encoder_layers, pooled_output = loaded_model(dummy_input)
+    all_encoder_layers, pooled_output = loaded_model(*dummy_input)
 
 Using a traced model for inference
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

docs/source/task_summary.rst

@@ -15,18 +15,17 @@ checkpoints are usually pre-trained on a large corpus of data and fine-tuned on
 following:
 
 - Not all models were fine-tuned on all tasks. If you want to fine-tune a model on a specific task, you can leverage
-  one of the `run_$TASK.py` script in the
-  `examples <https://github.com/huggingface/transformers/tree/master/examples>`_ directory.
+  one of the `run_$TASK.py` scripts in the
+  `examples <https://github.com/huggingface/transformers/tree/master/examples>`__ directory.
 - Fine-tuned models were fine-tuned on a specific dataset. This dataset may or may not overlap with your use-case
   and domain. As mentioned previously, you may leverage the
-  `examples <https://github.com/huggingface/transformers/tree/master/examples>`_ scripts to fine-tune your model, or you
+  `examples <https://github.com/huggingface/transformers/tree/master/examples>`__ scripts to fine-tune your model, or you
   may create your own training script.
 
 In order to do an inference on a task, several mechanisms are made available by the library:
 
 - Pipelines: very easy-to-use abstractions, which require as little as two lines of code.
-- Using a model directly with a tokenizer (PyTorch/TensorFlow): the full inference using the model. Less abstraction,
-  but much more powerful.
+- Direct model use: Less abstractions, but more flexibility and power via a direct access to a tokenizer (PyTorch/TensorFlow) and full inference capacity.
 
 Both approaches are showcased here.
 
@@ -44,10 +43,11 @@ Sequence Classification
 Sequence classification is the task of classifying sequences according to a given number of classes. An example
 of sequence classification is the GLUE dataset, which is entirely based on that task. If you would like to fine-tune
 a model on a GLUE sequence classification task, you may leverage the
-`run_glue.py <https://github.com/huggingface/transformers/tree/master/examples/text-classification/run_glue.py>`_ or
-`run_tf_glue.py <https://github.com/huggingface/transformers/tree/master/examples/text-classification/run_tf_glue.py>`_ scripts.
+`run_glue.py <https://github.com/huggingface/transformers/tree/master/examples/text-classification/run_glue.py>`__ and
+`run_pl_glue.py <https://github.com/huggingface/transformers/tree/master/examples/text-classification/run_pl_glue.py>`__ or
+`run_tf_glue.py <https://github.com/huggingface/transformers/tree/master/examples/text-classification/run_tf_glue.py>`__ scripts.
 
-Here is an example using the pipelines do to sentiment analysis: identifying if a sequence is positive or negative.
+Here is an example of using pipelines to do sentiment analysis: identifying if a sequence is positive or negative.
 It leverages a fine-tuned model on sst2, which is a GLUE task.
 
 This returns a label ("POSITIVE" or "NEGATIVE") alongside a score, as follows:
@@ -70,15 +70,17 @@ This returns a label ("POSITIVE" or "NEGATIVE") alongside a score, as follows:
 Here is an example of doing a sequence classification using a model to determine if two sequences are paraphrases
 of each other. The process is the following:
 
-- Instantiate a tokenizer and a model from the checkpoint name. The model is identified as a BERT model and loads it
-  with the weights stored in the checkpoint.
-- Build a sequence from the two sentences, with the correct model-specific separators token type ids
-  and attention masks (:func:`~transformers.PreTrainedTokenizer.encode` and
-  :func:`~transformers.PreTrainedTokenizer.__call__` take care of this)
-- Pass this sequence through the model so that it is classified in one of the two available classes: 0
-  (not a paraphrase) and 1 (is a paraphrase)
-- Compute the softmax of the result to get probabilities over the classes
-- Print the results
+1. Instantiate a tokenizer and a model from the checkpoint name. The model is
+   identified as a BERT model and loads it with the weights stored in the
+   checkpoint.
+2. Build a sequence from the two sentences, with the correct model-specific
+   separators token type ids and attention masks
+   (:func:`~transformers.PreTrainedTokenizer.encode` and
+   :func:`~transformers.PreTrainedTokenizer.__call__` take care of this).
+3. Pass this sequence through the model so that it is classified in one of the
+   two available classes: 0 (not a paraphrase) and 1 (is a paraphrase).
+4. Compute the softmax of the result to get probabilities over the classes.
+5. Print the results.
 
 .. code-block::
 
@@ -154,9 +156,12 @@ Extractive Question Answering
 
 Extractive Question Answering is the task of extracting an answer from a text given a question. An example of a
 question answering dataset is the SQuAD dataset, which is entirely based on that task. If you would like to fine-tune
-a model on a SQuAD task, you may leverage the `run_squad.py`.
+a model on a SQuAD task, you may leverage the
+`run_squad.py <https://github.com/huggingface/transformers/tree/master/examples/question-answering/run_squad.py>`__ and
+`run_tf_squad.py <https://github.com/huggingface/transformers/tree/master/examples/question-answering/run_tf_squad.py>`__ scripts.
 
-Here is an example using the pipelines do to question answering: extracting an answer from a text given a question.
+
+Here is an example of using pipelines to do question answering: extracting an answer from a text given a question.
 It leverages a fine-tuned model on SQuAD.
 
 .. code-block::
@@ -171,7 +176,7 @@ It leverages a fine-tuned model on SQuAD.
     ... a model on a SQuAD task, you may leverage the examples/question-answering/run_squad.py script.
     ... """
 
-This returns an answer extracted from the text, a confidence score, alongside "start" and "end" values which
+This returns an answer extracted from the text, a confidence score, alongside "start" and "end" values, which
 are the positions of the extracted answer in the text.
 
 .. code-block::
@@ -187,16 +192,19 @@ are the positions of the extracted answer in the text.
 
 Here is an example of question answering using a model and a tokenizer. The process is the following:
 
-- Instantiate a tokenizer and a model from the checkpoint name. The model is identified as a BERT model and loads it
-  with the weights stored in the checkpoint.
-- Define a text and a few questions.
-- Iterate over the questions and build a sequence from the text and the current question, with the correct
-  model-specific separators token type ids and attention masks
-- Pass this sequence through the model. This outputs a range of scores across the entire sequence tokens (question and
-  text), for both the start and end positions.
-- Compute the softmax of the result to get probabilities over the tokens
-- Fetch the tokens from the identified start and stop values, convert those tokens to a string.
-- Print the results
+1. Instantiate a tokenizer and a model from the checkpoint name. The model is
+   identified as a BERT model and loads it with the weights stored in the
+   checkpoint.
+2. Define a text and a few questions.
+3. Iterate over the questions and build a sequence from the text and the current
+   question, with the correct model-specific separators token type ids and
+   attention masks.
+4. Pass this sequence through the model. This outputs a range of scores across
+   the entire sequence tokens (question and text), for both the start and end
+   positions.
+5. Compute the softmax of the result to get probabilities over the tokens.
+6. Fetch the tokens from the identified start and stop values, convert those tokens to a string.
+7. Print the results.
 
 .. code-block::
 
@@ -291,8 +299,8 @@ Here is an example of question answering using a model and a tokenizer. The proc
 Language Modeling
 ----------------------------------------------------
 
-Language modeling is the task of fitting a model to a corpus, which can be domain specific. All popular transformer
-based models are trained using a variant of language modeling, e.g. BERT with masked language modeling, GPT-2 with
+Language modeling is the task of fitting a model to a corpus, which can be domain specific. All popular transformer-based
+models are trained using a variant of language modeling, e.g. BERT with masked language modeling, GPT-2 with
 causal language modeling.
 
 Language modeling can be useful outside of pre-training as well, for example to shift the model distribution to be
@@ -305,7 +313,7 @@ Masked Language Modeling
 Masked language modeling is the task of masking tokens in a sequence with a masking token, and prompting the model to
 fill that mask with an appropriate token. This allows the model to attend to both the right context (tokens on the
 right of the mask) and the left context (tokens on the left of the mask). Such a training creates a strong basis
-for downstream tasks requiring bi-directional context such as SQuAD (question answering,
+for downstream tasks, requiring bi-directional context such as SQuAD (question answering,
 see `Lewis, Lui, Goyal et al. <https://arxiv.org/abs/1910.13461>`__, part 4.2).
 
 Here is an example of using pipelines to replace a mask from a sequence:
@@ -316,7 +324,7 @@ Here is an example of using pipelines to replace a mask from a sequence:
 
     >>> nlp = pipeline("fill-mask")
 
-This outputs the sequences with the mask filled, the confidence score as well as the token id in the tokenizer
+This outputs the sequences with the mask filled, the confidence score, and the token id in the tokenizer
 vocabulary:
 
 .. code-block::
@@ -349,17 +357,19 @@ vocabulary:
       'token': 17715,
       'token_str': 'Ġprototype'}]
 
-Here is an example doing masked language modeling using a model and a tokenizer. The process is the following:
+Here is an example of doing masked language modeling using a model and a tokenizer. The process is the following:
 
-- Instantiate a tokenizer and a model from the checkpoint name. The model is identified as a DistilBERT model and
-  loads it with the weights stored in the checkpoint.
-- Define a sequence with a masked token, placing the :obj:`tokenizer.mask_token` instead of a word.
-- Encode that sequence into IDs and find the position of the masked token in that list of IDs.
-- Retrieve the predictions at the index of the mask token: this tensor has the same size as the vocabulary, and the
-  values are the scores attributed to each token. The model gives higher score to tokens he deems probable in that
-  context.
-- Retrieve the top 5 tokens using the PyTorch :obj:`topk` or TensorFlow :obj:`top_k` methods.
-- Replace the mask token by the tokens and print the results
+1. Instantiate a tokenizer and a model from the checkpoint name. The model is
+   identified as a DistilBERT model and loads it with the weights stored in the
+   checkpoint.
+2. Define a sequence with a masked token, placing the :obj:`tokenizer.mask_token` instead of a word.
+3. Encode that sequence into a list of IDs and find the position of the masked token in that list.
+4. Retrieve the predictions at the index of the mask token: this tensor has the
+   same size as the vocabulary, and the values are the scores attributed to each
+   token. The model gives higher score to tokens it deems probable in that
+   context.
+5. Retrieve the top 5 tokens using the PyTorch :obj:`topk` or TensorFlow :obj:`top_k` methods.
+6. Replace the mask token by the tokens and print the results
 
 .. code-block::
 
@@ -419,7 +429,7 @@ for generation tasks.
 
 Usually, the next token is predicted by sampling from the logits of the last hidden state the model produces from the input sequence.
 
-Here is an example using the tokenizer and model and leveraging the :func:`~transformers.PreTrainedModel.top_k_top_p_filtering` method to sample the next token following an input sequence of tokens.
+Here is an example of using the tokenizer and model and leveraging the :func:`~transformers.PreTrainedModel.top_k_top_p_filtering` method to sample the next token following an input sequence of tokens.
 
 .. code-block::
 
@@ -473,7 +483,7 @@ Here is an example using the tokenizer and model and leveraging the :func:`~tran
     >>> resulting_string = tokenizer.decode(generated.numpy().tolist()[0])
 
 
-This outputs a (hopefully) coherent next token following the original sequence, which is in our case is the word *has*:
+This outputs a (hopefully) coherent next token following the original sequence, which in our case is the word *has*:
 
 .. code-block::
 
@@ -485,7 +495,7 @@ In the next section, we show how this functionality is leveraged in :func:`~tran
 Text Generation
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-In text generation (*a.k.a* *open-ended text generation*) the goal is to create a coherent portion of text that is a continuation from the given context. As an example, is it shown how *GPT-2* can be used in pipelines to generate text. As a default all models apply *Top-K* sampling when used in pipelines as configured in their respective configurations (see `gpt-2 config <https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-config.json>`_ for example).
+In text generation (*a.k.a* *open-ended text generation*) the goal is to create a coherent portion of text that is a continuation from the given context. The following example shows how *GPT-2* can be used in pipelines to generate text. As a default all models apply *Top-K* sampling when used in pipelines, as configured in their respective configurations (see `gpt-2 config <https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-config.json>`__ for example).
 
 .. code-block::
 
@@ -497,10 +507,10 @@ In text generation (*a.k.a* *open-ended text generation*) the goal is to create
 
 
 
-Here the model generates a random text with a total maximal length of *50* tokens from context *"As far as I am concerned, I will"*.
-The default arguments of ``PreTrainedModel.generate()`` can directly be overriden in the pipeline as is shown above for the argument ``max_length``.
+Here, the model generates a random text with a total maximal length of *50* tokens from context *"As far as I am concerned, I will"*.
+The default arguments of ``PreTrainedModel.generate()`` can be directly overriden in the pipeline, as is shown above for the argument ``max_length``.
 
-Here is an example for text generation using XLNet and its tokenzier. 
+Here is an example of text generation using ``XLNet`` and its tokenzier.
 
 .. code-block::
 
@@ -556,24 +566,27 @@ Here is an example for text generation using XLNet and its tokenzier.
 
 .. code-block::
 
-    print(generated)
+    >>> print(generated)
+    Today the weather is really nice and I am planning on anning on taking a nice...... of a great time!<eop>...............
 
-Text generation is currently possible with *GPT-2*, *OpenAi-GPT*, *CTRL*, *XLNet*, *Transfo-XL* and *Reformer* in PyTorch and for most models in Tensorflow as well. As can be seen in the example above *XLNet* and *Transfo-xl* often need to be padded to work well.
-GPT-2 is usually a good choice for *open-ended text generation* because it was trained on millions on webpages with a causal language modeling objective.
+Text generation is currently possible with *GPT-2*, *OpenAi-GPT*, *CTRL*, *XLNet*, *Transfo-XL* and *Reformer* in PyTorch and for most models in Tensorflow as well. As can be seen in the example above *XLNet* and *Transfo-XL* often need to be padded to work well.
+GPT-2 is usually a good choice for *open-ended text generation* because it was trained on millions of webpages with a causal language modeling objective.
 
-For more information on how to apply different decoding strategies for text generation, please also refer to our generation blog post `here <https://huggingface.co/blog/how-to-generate>`_.
+For more information on how to apply different decoding strategies for text generation, please also refer to our text generation blog post `here <https://huggingface.co/blog/how-to-generate>`__.
 
 
 Named Entity Recognition
 ----------------------------------------------------
 
-Named Entity Recognition (NER) is the task of classifying tokens according to a class, for example identifying a
+Named Entity Recognition (NER) is the task of classifying tokens according to a class, for example, identifying a
 token as a person, an organisation or a location.
 An example of a named entity recognition dataset is the CoNLL-2003 dataset, which is entirely based on that task.
-If you would like to fine-tune a model on an NER task, you may leverage the `ner/run_ner.py` (PyTorch),
-`ner/run_pl_ner.py` (leveraging pytorch-lightning) or the `ner/run_tf_ner.py` (TensorFlow) scripts.
+If you would like to fine-tune a model on an NER task, you may leverage the
+`run_ner.py <https://github.com/huggingface/transformers/tree/master/examples/token-classification/run_ner.py>`__ (PyTorch),
+`run_pl_ner.py <https://github.com/huggingface/transformers/tree/master/examples/token-classification/run_pl_ner.py>`__ (leveraging pytorch-lightning) or the
+`run_tf_ner.py <https://github.com/huggingface/transformers/tree/master/examples/token-classification/run_tf_ner.py>`__ (TensorFlow) scripts.
 
-Here is an example using the pipelines do to named entity recognition, trying to identify tokens as belonging to one
+Here is an example of using pipelines to do named entity recognition, specifically, trying to identify tokens as belonging to one
 of 9 classes:
 
 - O, Outside of a named entity
@@ -599,7 +612,7 @@ It leverages a fine-tuned model on CoNLL-2003, fine-tuned by `@stefan-it <https:
     ...            "close to the Manhattan Bridge which is visible from the window."
 
 
-This outputs a list of all words that have been identified as an entity from the 9 classes defined above. Here is the
+This outputs a list of all words that have been identified as one of the entities from the 9 classes defined above. Here are the
 expected results:
 
 .. code-block::
@@ -620,22 +633,25 @@ expected results:
         {'word': 'Bridge', 'score': 0.990249514579773, 'entity': 'I-LOC'}
     ]
 
-Note how the words "Hugging Face" have been identified as an organisation, and "New York City", "DUMBO" and
+Note, how the tokens of the sequence "Hugging Face" have been identified as an organisation, and "New York City", "DUMBO" and
 "Manhattan Bridge" have been identified as locations.
 
-Here is an example doing named entity recognition using a model and a tokenizer. The process is the following:
+Here is an example of doing named entity recognition, using a model and a tokenizer. The process is the following:
 
-- Instantiate a tokenizer and a model from the checkpoint name. The model is identified as a BERT model and
-  loads it with the weights stored in the checkpoint.
-- Define the label list with which the model was trained on.
-- Define a sequence with known entities, such as "Hugging Face" as an organisation and "New York City" as a location.
-- Split words into tokens so that they can be mapped to the predictions. We use a small hack by firstly completely
-  encoding and decoding the sequence, so that we're left with a string that contains the special tokens.
-- Encode that sequence into IDs (special tokens are added automatically).
-- Retrieve the predictions by passing the input to the model and getting the first output. This results in a
-  distribution over the 9 possible classes for each token. We take the argmax to retrieve the most likely class
-  for each token.
-- Zip together each token with its prediction and print it.
+1. Instantiate a tokenizer and a model from the checkpoint name. The model is
+   identified as a BERT model and loads it with the weights stored in the
+   checkpoint.
+2. Define the label list with which the model was trained on.
+3. Define a sequence with known entities, such as "Hugging Face" as an organisation and "New York City" as a location.
+4. Split words into tokens so that they can be mapped to predictions. We use a
+   small hack by, first, completely encoding and decoding the sequence, so that
+   we're left with a string that contains the special tokens.
+5. Encode that sequence into IDs (special tokens are added automatically).
+6. Retrieve the predictions by passing the input to the model and getting the
+   first output. This results in a distribution over the 9 possible classes for
+   each token. We take the argmax to retrieve the most likely class for each
+   token.
+7. Zip together each token with its prediction and print it.
 
 .. code-block::
 
@@ -697,8 +713,8 @@ Here is an example doing named entity recognition using a model and a tokenizer.
     >>> predictions = tf.argmax(outputs, axis=2)
 
 
-This outputs a list of each token mapped to their prediction. Differently from the pipeline, here every token has
-a prediction as we didn't remove the "0" class which means that no particular entity was found on that token. The
+This outputs a list of each token mapped to its corresponding prediction. Differently from the pipeline, here every token has
+a prediction as we didn't remove the "0"th class, which means that no particular entity was found on that token. The
 following array should be the output:
 
 .. code-block::
@@ -709,13 +725,13 @@ following array should be the output:
 Summarization
 ----------------------------------------------------
 
-Summarization is the task of summarizing a text / an article into a shorter text.
+Summarization is the task of summarizing a document or an article into a shorter text.
 
 An example of a summarization dataset is the CNN / Daily Mail dataset, which consists of long news articles and was created for the task of summarization.
-If you would like to fine-tune a model on a summarization task, you may leverage the ``examples/summarization/bart/run_train.sh`` (leveraging pytorch-lightning) script.
+If you would like to fine-tune a model on a summarization task, various approaches are described in this
+`document <https://github.com/huggingface/transformers/blob/master/examples/seq2seq/README.md>`__.
 
-Here is an example using the pipelines do to summarization. 
-It leverages a Bart model that was fine-tuned on the CNN / Daily Mail data set.
+Here is an example of using the pipelines to do summarization. It leverages a Bart model that was fine-tuned on the CNN / Daily Mail data set.
 
 .. code-block::
 
@@ -742,8 +758,8 @@ It leverages a Bart model that was fine-tuned on the CNN / Daily Mail data set.
     ... If convicted, Barrientos faces up to four years in prison.  Her next court appearance is scheduled for May 18.
     ... """
 
-Because the summarization pipeline depends on the ``PretrainedModel.generate()`` method, we can override the default arguments 
-of ``PretrainedModel.generate()`` directly in the pipeline as is shown for ``max_length`` and ``min_length`` above.
+Because the summarization pipeline depends on the ``PretrainedModel.generate()`` method, we can override the default arguments
+of ``PretrainedModel.generate()`` directly in the pipeline for ``max_length`` and ``min_length`` as shown below.
 This outputs the following summary:
 
 .. code-block::
@@ -751,14 +767,15 @@ This outputs the following summary:
     >>> print(summarizer(ARTICLE, max_length=130, min_length=30, do_sample=False))
     [{'summary_text': 'Liana Barrientos, 39, is charged with two counts of "offering a false instrument for filing in the first degree" In total, she has been married 10 times, with nine of her marriages occurring between 1999 and 2002. She is believed to still be married to four men.'}]
 
-Here is an example doing summarization using a model and a tokenizer. The process is the following:
+Here is an example of doing summarization using a model and a tokenizer. The process is the following:
 
-- Instantiate a tokenizer and a model from the checkpoint name. Summarization is usually done using an encoder-decoder model, such as ``Bart`` or ``T5``.
-- Define the article that should be summarizaed.
-- Leverage the ``PretrainedModel.generate()`` method.
-- Add the T5 specific prefix "summarize: ".
+1. Instantiate a tokenizer and a model from the checkpoint name. Summarization is usually done using an encoder-decoder model, such as ``Bart`` or ``T5``.
+2. Define the article that should be summarized.
+3. Add the T5 specific prefix "summarize: ".
+4. Use the ``PretrainedModel.generate()`` method to generate the summary.
+
+In this example we use Google`s T5 model. Even though it was pre-trained only on a multi-task mixed dataset (including CNN / Daily Mail), it yields very good results.
 
-Here Google`s T5 model is used that was only pre-trained on a multi-task mixed data set (including CNN / Daily Mail), but nevertheless yields very good results.
 .. code-block::
 
     >>> ## PYTORCH CODE
@@ -785,12 +802,14 @@ Translation
 
 Translation is the task of translating a text from one language to another.
 
-An example of a translation dataset is the WMT English to German dataset, which has English sentences as the input data 
-and German sentences as the target data.
+An example of a translation dataset is the WMT English to German dataset, which has sentences in English as the input data
+and the corresponding sentences in German as the target data.
+If you would like to fine-tune a model on a translation task, various approaches are described in this
+`document <https://github.com/huggingface/transformers/blob/master/examples/seq2seq/README.md>`__.
 
-Here is an example using the pipelines do to translation. 
-It leverages a T5 model that was only pre-trained on a multi-task mixture dataset (including WMT), but yields impressive 
-translation results nevertheless.
+Here is an example of using the pipelines to do translation.
+It leverages a T5 model that was only pre-trained on a multi-task mixture dataset (including WMT), yet, yielding impressive
+translation results.
 
 .. code-block::
 
@@ -800,15 +819,15 @@ translation results nevertheless.
     >>> print(translator("Hugging Face is a technology company based in New York and Paris", max_length=40))
     [{'translation_text': 'Hugging Face ist ein Technologieunternehmen mit Sitz in New York und Paris.'}]
 
-Because the translation pipeline depends on the ``PretrainedModel.generate()`` method, we can override the default arguments 
+Because the translation pipeline depends on the ``PretrainedModel.generate()`` method, we can override the default arguments
 of ``PretrainedModel.generate()`` directly in the pipeline as is shown for ``max_length`` above.
-  
-Here is an example doing translation using a model and a tokenizer. The process is the following:
 
-- Instantiate a tokenizer and a model from the checkpoint name. Summarization is usually done using an encoder-decoder model, such as ``Bart`` or ``T5``.
-- Define the article that should be summarizaed.
-- Leverage the ``PretrainedModel.generate()`` method.
-- Add the T5 specific prefix "translate English to German: "
+Here is an example of doing translation using a model and a tokenizer. The process is the following:
+
+1. Instantiate a tokenizer and a model from the checkpoint name. Summarization is usually done using an encoder-decoder model, such as ``Bart`` or ``T5``.
+2. Define the article that should be summarizaed.
+3. Add the T5 specific prefix "translate English to German: "
+4. Use the ``PretrainedModel.generate()`` method to perform the translation.
 
 .. code-block::
 
@@ -820,10 +839,6 @@ Here is an example doing translation using a model and a tokenizer. The process
 
     >>> inputs = tokenizer.encode("translate English to German: Hugging Face is a technology company based in New York and Paris", return_tensors="pt")
     >>> outputs = model.generate(inputs, max_length=40, num_beams=4, early_stopping=True)
-
-    >>> print(outputs)
-    tensor([[    0, 11560,  3896,  8881,   229,   236,     3, 14366, 15377,   181,
-             11216,    16,   368,  1060,    64,  1919,     5]])
     >>> ## TENSORFLOW CODE
     >>> from transformers import TFAutoModelWithLMHead, AutoTokenizer
 
@@ -833,7 +848,9 @@ Here is an example doing translation using a model and a tokenizer. The process
     >>> inputs = tokenizer.encode("translate English to German: Hugging Face is a technology company based in New York and Paris", return_tensors="tf")
     >>> outputs = model.generate(inputs, max_length=40, num_beams=4, early_stopping=True)
 
-    >>> print(outputs)
-    tf.Tensor(
-    [[    0 11560  3896  8881   229   236     3 14366 15377   181 11216    16
-        368  1060    64  1919     5]], shape=(1, 17), dtype=int32)
+As with the pipeline example, we get the same translation:
+
+.. code-block::
+
+    >>> print(tokenizer.decode(outputs[0]))
+    Hugging Face ist ein Technologieunternehmen mit Sitz in New York und Paris.

docs/source/testing.rst

@@ -0,0 +1,936 @@
+Testing
+==========
+
+
+Let's take a look at how 🤗 Transformer models are tested and how you can write new tests and improve the existing ones.
+
+There are 2 test suites in the repository:
+
+1. ``tests`` -- tests for the general API
+2. ``examples`` -- tests primarily for various applications that aren't part of the API
+
+How transformers are tested
+---------------------------
+
+1. Once a PR is submitted it gets tested with 9 CircleCi jobs. Every new commit to that PR gets retested. These jobs are defined in this `config file <https://github.com/huggingface/transformers/blob/master/.circleci/config.yml>`__, so that if needed you can reproduce the same environment on your machine.
+   
+   These CI jobs don't run ``@slow`` tests.
+   
+2. There are 3 jobs run by `github actions <https://github.com/huggingface/transformers/actions>`__:
+
+   * `torch hub integration <https://github.com/huggingface/transformers/blob/master/.github/workflows/github-torch-hub.yml>`__:  checks whether torch hub integration works.
+
+   * `self-hosted (push) <https://github.com/huggingface/transformers/blob/master/.github/workflows/self-push.yml>`__: runs fast tests on GPU only on commits on ``master``. It only runs if a commit on ``master`` has updated the code in one of the following folders: ``src``, ``tests``, ``.github`` (to prevent running on added model cards, notebooks, etc.)
+     
+   * `self-hosted runner <https://github.com/huggingface/transformers/blob/master/.github/workflows/self-scheduled.yml>`__: runs slow tests on ``tests`` and ``examples``:
+
+   .. code-block:: bash
+
+    RUN_SLOW=1 USE_CUDA=1 pytest tests/
+    RUN_SLOW=1 USE_CUDA=1 pytest examples/
+
+   The results can be observed `here <https://github.com/huggingface/transformers/actions>`__.
+
+
+
+Running tests
+-------------
+
+
+
+
+
+Choosing which tests to run
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This document goes into many details of how tests can be run. If after reading everything, you need even more details you will find them `here <https://docs.pytest.org/en/latest/usage.html>`__.
+
+Here are some most useful ways of running tests.
+
+Run all:
+
+.. code-block:: console
+
+   pytest
+
+or:
+
+.. code-block:: bash
+
+   make test
+
+Note that the latter is defined as:
+
+.. code-block:: bash
+
+   python -m pytest -n auto --dist=loadfile -s -v ./tests/
+
+which tells pytest to:
+
+* run as many test processes as they are CPU cores (which could be too many if you don't have a ton of RAM!)
+* ensure that all tests from the same file will be run by the same test process
+* do not capture output
+* run in verbose mode
+
+
+
+Getting the list of all tests
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+All tests of the test suite:
+
+.. code-block:: bash
+
+   pytest --collect-only -q
+
+All tests of a given test file:
+
+.. code-block:: bash
+
+   pytest tests/test_optimization.py --collect-only -q
+
+
+   
+Run a specific test module
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To run an individual test module:
+
+.. code-block:: bash
+
+   pytest tests/test_logging.py
+   
+
+Run specific tests
+~~~~~~~~~~~~~~~~~~
+
+Since unittest is used inside most of the tests, to run specific subtests you need to know the name of the unittest class containing those tests. For example, it could be:
+
+.. code-block:: bash
+
+   pytest tests/test_optimization.py::OptimizationTest::test_adam_w
+
+Here:
+
+* ``tests/test_optimization.py`` - the file with tests
+* ``OptimizationTest`` - the name of the class
+* ``test_adam_w`` - the name of the specific test function
+
+If the file contains multiple classes, you can choose to run only tests of a given class. For example:
+
+.. code-block:: bash
+
+   pytest tests/test_optimization.py::OptimizationTest
+
+
+will run all the tests inside that class.
+
+As mentioned earlier you can see what tests are contained inside the ``OptimizationTest`` class by running:
+
+.. code-block:: bash
+
+   pytest tests/test_optimization.py::OptimizationTest --collect-only -q
+
+  
+You can run tests by keyword expressions.
+
+To run only tests whose name contains ``adam``:
+
+.. code-block:: bash
+
+   pytest -k adam tests/test_optimization.py
+
+To run all tests except those whose name contains ``adam``:
+
+.. code-block:: bash
+
+   pytest -k "not adam" tests/test_optimization.py
+
+And you can combine the two patterns in one:
+
+
+.. code-block:: bash
+
+   pytest -k "ada and not adam" tests/test_optimization.py
+
+
+
+Run only modified tests
+~~~~~~~~~~~~~~~~~~~~~~~
+
+You can run the tests related to the unstaged files or the current branch (according to Git) by using `pytest-picked <https://github.com/anapaulagomes/pytest-picked>`__. This is a great way of quickly testing your changes didn't break anything, since it won't run the tests related to files you didn't touch.
+
+.. code-block:: bash
+
+    pip install pytest-picked
+
+.. code-block:: bash
+
+    pytest --picked
+
+All tests will be run from files and folders which are modified, but not
+yet committed.
+
+Automatically rerun failed tests on source modification
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+`pytest-xdist <https://github.com/pytest-dev/pytest-xdist>`__ provides a
+very useful feature of detecting all failed tests, and then waiting for
+you to modify files and continuously re-rerun those failing tests until
+they pass while you fix them. So that you don't need to re start pytest
+after you made the fix. This is repeated until all tests pass after
+which again a full run is performed.
+
+.. code-block:: bash
+
+    pip install pytest-xdist
+
+To enter the mode: ``pytest -f`` or ``pytest --looponfail``
+
+File changes are detected by looking at ``looponfailroots`` root
+directories and all of their contents (recursively). If the default for
+this value does not work for you, you can change it in your project by
+setting a configuration option in ``setup.cfg``:
+
+.. code-block:: ini
+
+    [tool:pytest]
+    looponfailroots = transformers tests
+
+or ``pytest.ini``/``tox.ini`` files:
+
+.. code-block:: ini
+
+    [pytest]
+    looponfailroots = transformers tests
+
+This would lead to only looking for file changes in the respective
+directories, specified relatively to the ini-file’s directory.
+
+`pytest-watch <https://github.com/joeyespo/pytest-watch>`__ is an
+alternative implementation of this functionality.
+
+
+Skip a test module
+~~~~~~~~~~~~~~~~~~
+
+If you want to run all test modules, except a few you can exclude them by giving an explicit list of tests to run. For example, to run all except ``test_modeling_*.py`` tests:
+
+.. code-block:: bash
+
+   pytest `ls -1 tests/*py | grep -v test_modeling`
+
+
+Clearing state
+~~~~~~~~~~~~~~
+
+CI builds and when isolation is important (against speed), cache should
+be cleared:
+
+.. code-block:: bash
+
+    pytest --cache-clear tests
+
+Running tests in parallel
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+As mentioned earlier ``make test`` runs tests in parallel via ``pytest-xdist`` plugin (``-n X`` argument, e.g. ``-n 2`` to run 2 parallel jobs).
+
+``pytest-xdist``'s ``--dist=`` option allows one to control how the tests are grouped. ``--dist=loadfile`` puts the tests located in one file onto the same process.
+
+Since the order of executed tests is different and unpredictable, if
+running the test suite with ``pytest-xdist`` produces failures (meaning
+we have some undetected coupled tests), use
+`pytest-replay <https://github.com/ESSS/pytest-replay>`__ to replay the
+tests in the same order, which should help with then somehow reducing
+that failing sequence to a minimum.
+
+Test order and repetition
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+It's good to repeat the tests several times, in sequence, randomly, or
+in sets, to detect any potential inter-dependency and state-related bugs
+(tear down). And the straightforward multiple repetition is just good to
+detect some problems that get uncovered by randomness of DL.
+
+
+Repeat tests
+^^^^^^^^^^^^
+
+* `pytest-flakefinder <https://github.com/dropbox/pytest-flakefinder>`__:
+
+.. code-block:: bash
+
+   pip install pytest-flakefinder
+
+And then run every test multiple times (50 by default):
+
+.. code-block:: bash
+
+   pytest --flake-finder --flake-runs=5 tests/test_failing_test.py
+   
+.. note::
+   This plugin doesn't work with ``-n`` flag from ``pytest-xdist``.
+   
+.. note::
+   There is another plugin ``pytest-repeat``, but it doesn't work with ``unittest``.
+
+
+Run tests in a random order
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+.. code-block:: bash
+
+    pip install pytest-random-order
+
+Important: the presence of ``pytest-random-order`` will automatically
+randomize tests, no configuration change or command line options is
+required.
+
+As explained earlier this allows detection of coupled tests - where one
+test's state affects the state of another. When ``pytest-random-order``
+is installed it will print the random seed it used for that session,
+e.g:
+
+.. code-block:: bash
+
+   pytest tests
+   [...]
+   Using --random-order-bucket=module
+   Using --random-order-seed=573663
+
+So that if the given particular sequence fails, you can reproduce it by
+adding that exact seed, e.g.:
+
+.. code-block:: bash
+
+   pytest --random-order-seed=573663
+   [...]
+   Using --random-order-bucket=module
+   Using --random-order-seed=573663
+
+It will only reproduce the exact order if you use the exact same list of
+tests (or no list at all). Once you start to manually narrowing
+down the list you can no longer rely on the seed, but have to list them
+manually in the exact order they failed and tell pytest to not randomize
+them instead using ``--random-order-bucket=none``, e.g.:
+
+.. code-block:: bash
+
+   pytest --random-order-bucket=none tests/test_a.py tests/test_c.py tests/test_b.py
+
+To disable the shuffling for all tests:
+
+.. code-block:: bash
+
+    pytest --random-order-bucket=none
+
+By default ``--random-order-bucket=module`` is implied, which will
+shuffle the files on the module levels. It can also shuffle on
+``class``, ``package``, ``global`` and ``none`` levels. For the complete
+details please see its `documentation <https://github.com/jbasko/pytest-random-order>`__.
+
+Another randomization alternative is: ``pytest-randomly`` <https://github.com/pytest-dev/pytest-randomly>`__. This module has a very similar functionality/interface, but it doesn't have the bucket modes available in ``pytest-random-order``. It has the same problem of imposing itself once installed.
+
+Look and feel variations
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+pytest-sugar
+^^^^^^^^^^^^
+
+`pytest-sugar <https://github.com/Frozenball/pytest-sugar>`__ is a
+plugin that improves the look-n-feel, adds a progressbar, and show tests
+that fail and the assert instantly. It gets activated automatically upon
+installation.
+
+.. code-block:: bash
+                
+   pip install pytest-sugar
+
+To run tests without it, run:
+
+.. code-block:: bash
+
+    pytest -p no:sugar
+
+or uninstall it.
+
+
+
+Report each sub-test name and its progress
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+For a single or a group of tests via ``pytest`` (after
+``pip install pytest-pspec``):
+
+.. code-block:: bash
+
+   pytest --pspec tests/test_optimization.py 
+
+
+
+Instantly shows failed tests
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+`pytest-instafail <https://github.com/pytest-dev/pytest-instafail>`__
+shows failures and errors instantly instead of waiting until the end of
+test session.
+
+.. code-block:: bash
+
+    pip install pytest-instafail
+
+.. code-block:: bash
+
+    pytest --instafail
+
+To GPU or not to GPU
+~~~~~~~~~~~~~~~~~~~~
+
+On a GPU-enabled setup, to test in CPU-only mode add ``CUDA_VISIBLE_DEVICES=""``:
+
+.. code-block:: bash
+                
+    CUDA_VISIBLE_DEVICES="" pytest tests/test_logging.py
+
+or if you have multiple gpus, you can tell which one to use in this test session, e.g. to use only the second gpu if you have gpus ``0`` and ``1``, you can run:
+
+.. code-block:: bash
+                
+    CUDA_VISIBLE_DEVICES="1" pytest tests/test_logging.py
+
+This is handy when you want to run different tasks on different GPUs.
+    
+And we have these decorators that require the condition described by the marker.
+
+```
+@require_torch
+@require_tf
+@require_multigpu
+@require_non_multigpu
+@require_torch_tpu
+@require_torch_and_cuda
+```
+
+This section will be expanded soon once our work in progress on those decorators is finished.
+
+Inside tests:
+
+* How many GPUs are available:
+
+.. code-block:: bash
+
+   torch.cuda.device_count()
+
+
+   
+
+
+Output capture
+~~~~~~~~~~~~~~
+
+During test execution any output sent to ``stdout`` and ``stderr`` is
+captured. If a test or a setup method fails, its according captured
+output will usually be shown along with the failure traceback.
+
+To disable output capturing and to get the ``stdout`` and ``stderr``
+normally, use ``-s`` or ``--capture=no``:
+
+.. code-block:: bash
+
+   pytest -s tests/test_logging.py
+
+To send test results to JUnit format output:
+
+.. code-block:: bash
+
+   py.test tests --junitxml=result.xml
+
+
+Color control
+~~~~~~~~~~~~~
+
+To have no color (e.g., yellow on white background is not readable):
+
+.. code-block:: bash
+
+   pytest --color=no tests/test_logging.py
+
+
+
+Sending test report to online pastebin service
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Creating a URL for each test failure:
+
+.. code-block:: bash
+
+   pytest --pastebin=failed tests/test_logging.py
+
+This will submit test run information to a remote Paste service and
+provide a URL for each failure. You may select tests as usual or add for
+example -x if you only want to send one particular failure.
+
+Creating a URL for a whole test session log:
+
+.. code-block:: bash
+
+   pytest --pastebin=all tests/test_logging.py
+
+
+
+Writing tests
+-------------
+
+🤗 transformers tests are based on ``unittest``, but run by ``pytest``, so most of the time features from both systems can be used.
+
+You can read `here <https://docs.pytest.org/en/stable/unittest.html>`__ which features are supported, but the important thing to remember is that most ``pytest`` fixtures don't work. Neither parametrization, but we use the module ``parameterized`` that works in a similar way.
+
+
+Parametrization
+~~~~~~~~~~~~~~~
+
+Often, there is a need to run the same test multiple times, but with different arguments. It could be done from within the test, but then there is no way of running that test for just one set of arguments.
+
+.. code-block:: python
+                
+    # test_this1.py
+    import unittest
+    from parameterized import parameterized
+    class TestMathUnitTest(unittest.TestCase):
+        @parameterized.expand([
+            ("negative", -1.5, -2.0),
+            ("integer", 1, 1.0),
+            ("large fraction", 1.6, 1),
+        ])
+        def test_floor(self, name, input, expected):
+            assert_equal(math.floor(input), expected)
+
+Now, by default this test will be run 3 times, each time with the last 3 arguments of ``test_floor`` being assigned the corresponding arguments in the parameter list.
+
+and you could run just the ``negative`` and ``integer`` sets of params with:
+
+.. code-block:: bash
+
+   pytest -k "negative and integer" tests/test_mytest.py
+
+or all but ``negative`` sub-tests, with:
+
+.. code-block:: bash
+
+   pytest -k "not negative" tests/test_mytest.py
+
+Besides using the ``-k`` filter that was just mentioned, you can find out the exact name of each sub-test and run any or all of them using their exact names. 
+        
+.. code-block:: bash
+                
+    pytest test_this1.py --collect-only -q
+
+and it will list:
+                
+.. code-block:: bash
+
+    test_this1.py::TestMathUnitTest::test_floor_0_negative
+    test_this1.py::TestMathUnitTest::test_floor_1_integer
+    test_this1.py::TestMathUnitTest::test_floor_2_large_fraction
+
+So now you can run just 2 specific sub-tests:
+
+.. code-block:: bash
+
+    pytest test_this1.py::TestMathUnitTest::test_floor_0_negative  test_this1.py::TestMathUnitTest::test_floor_1_integer
+   
+The module `parameterized <https://pypi.org/project/parameterized/>`__ which is already in the developer dependencies of ``transformers`` works for both: ``unittests`` and ``pytest`` tests.
+
+If, however, the test is not a ``unittest``, you may use ``pytest.mark.parametrize`` (or you may see it being used in some existing tests, mostly under ``examples``).
+
+Here is the same example, this time using ``pytest``'s ``parametrize`` marker:
+
+.. code-block:: python
+
+    # test_this2.py
+    import pytest
+    @pytest.mark.parametrize(
+        "name, input, expected",
+        [
+            ("negative", -1.5, -2.0),
+            ("integer", 1, 1.0),
+            ("large fraction", 1.6, 1),
+        ],
+    )
+    def test_floor(name, input, expected):
+        assert_equal(math.floor(input), expected)
+
+Same as with ``parameterized``, with ``pytest.mark.parametrize`` you can have a fine control over which sub-tests are run, if the ``-k`` filter doesn't do the job. Except, this parametrization function creates a slightly different set of names for the sub-tests. Here is what they look like:
+        
+.. code-block:: bash
+                
+    pytest test_this2.py --collect-only -q
+
+and it will list:
+                
+.. code-block:: bash
+
+    test_this2.py::test_floor[integer-1-1.0]
+    test_this2.py::test_floor[negative--1.5--2.0]
+    test_this2.py::test_floor[large fraction-1.6-1]       
+
+So now you can run just the specific test:
+
+.. code-block:: bash
+
+    pytest test_this2.py::test_floor[negative--1.5--2.0] test_this2.py::test_floor[integer-1-1.0]
+
+as in the previous example.
+
+    
+
+Temporary files and directories
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Using unique temporary files and directories are essential for parallel test running, so that the tests won't overwrite each other's data. Also we want to get the temp files and directories removed at the end of each test that created them. Therefore, using packages like ``tempfile``, which address these needs is essential.
+
+However, when debugging tests, you need to be able to see what goes into the temp file or directory and you want to know it's exact path and not having it randomized on every test re-run.
+
+A helper class :obj:`transformers.test_utils.TestCasePlus` is best used for such purposes. It's a sub-class of :obj:`unittest.TestCase`, so we can easily inherit from it in the test modules.
+
+Here is an example of its usage:
+
+.. code-block:: python
+
+    from transformers.testing_utils import TestCasePlus
+    class ExamplesTests(TestCasePlus):
+    def test_whatever(self):
+        tmp_dir = self.get_auto_remove_tmp_dir()
+
+This code creates a unique temporary directory, and sets :obj:`tmp_dir` to its location.
+
+In this and all the following scenarios the temporary directory will be auto-removed at the end of test, unless ``after=False`` is passed to the helper function.
+
+* Create a temporary directory of my choice and delete it at the end - useful for debugging when you want to monitor a specific directory:
+
+.. code-block:: python
+
+    def test_whatever(self):
+        tmp_dir = self.get_auto_remove_tmp_dir(tmp_dir="./tmp/run/test")
+
+* Create a temporary directory of my choice and do not delete it at the end---useful for when you want to look at the temp results:
+
+.. code-block:: python
+
+    def test_whatever(self):
+        tmp_dir = self.get_auto_remove_tmp_dir(tmp_dir="./tmp/run/test", after=False)
+
+* Create a temporary directory of my choice and ensure to delete it right away---useful for when you disabled deletion in the previous test run and want to make sure the that temporary directory is empty before the new test is run:
+
+.. code-block:: python
+
+   def test_whatever(self):
+        tmp_dir = self.get_auto_remove_tmp_dir(tmp_dir="./tmp/run/test", before=True)
+
+.. note::
+   In order to run the equivalent of ``rm -r`` safely, only subdirs of the project repository checkout are allowed if an explicit obj:`tmp_dir` is used, so that by mistake no ``/tmp`` or similar important part of the filesystem will get nuked. i.e. please always pass paths that start with ``./``.
+
+.. note::
+   Each test can register multiple temporary directories and they all will get auto-removed, unless requested otherwise.
+
+
+Skipping tests
+~~~~~~~~~~~~~~
+
+This is useful when a bug is found and a new test is written, yet the
+bug is not fixed yet. In order to be able to commit it to the main
+repository we need make sure it's skipped during ``make test``.
+
+Methods:
+
+-  A **skip** means that you expect your test to pass only if some
+   conditions are met, otherwise pytest should skip running the test
+   altogether. Common examples are skipping windows-only tests on
+   non-windows platforms, or skipping tests that depend on an external
+   resource which is not available at the moment (for example a
+   database).
+
+-  A **xfail** means that you expect a test to fail for some reason. A
+   common example is a test for a feature not yet implemented, or a bug
+   not yet fixed. When a test passes despite being expected to fail
+   (marked with pytest.mark.xfail), it’s an xpass and will be reported
+   in the test summary.
+
+One of the important differences between the two is that ``skip``
+doesn't run the test, and ``xfail`` does. So if the code that's buggy
+causes some bad state that will affect other tests, do not use
+``xfail``.
+
+Implementation
+^^^^^^^^^^^^^^
+
+- Here is how to skip whole test unconditionally:
+
+.. code-block:: python
+
+    @unittest.skip("this bug needs to be fixed")
+    def test_feature_x():
+
+or via pytest:
+
+.. code-block:: python
+
+    @pytest.mark.skip(reason="this bug needs to be fixed")
+
+or the ``xfail`` way:
+
+.. code-block:: python
+
+    @pytest.mark.xfail
+    def test_feature_x():
+
+Here is how to skip a test based on some internal check inside the test:
+
+.. code-block:: python
+
+    def test_feature_x():
+        if not has_something():
+            pytest.skip("unsupported configuration")
+
+or the whole module:
+
+.. code-block:: python
+
+    import pytest
+    if not pytest.config.getoption("--custom-flag"):
+        pytest.skip("--custom-flag is missing, skipping tests", allow_module_level=True)
+
+or the ``xfail`` way:
+
+.. code-block:: python
+
+    def test_feature_x():
+        pytest.xfail("expected to fail until bug XYZ is fixed")
+
+Here is how to skip all tests in a module if some import is missing:
+
+.. code-block:: python
+
+    docutils = pytest.importorskip("docutils", minversion="0.3")
+
+-  Skip a test based on a condition:
+
+.. code-block:: python
+
+    @pytest.mark.skipif(sys.version_info < (3,6), reason="requires python3.6 or higher")
+    def test_feature_x():
+
+or:
+
+.. code-block:: python
+
+    @unittest.skipIf(torch_device == "cpu", "Can't do half precision")
+    def test_feature_x():
+   
+or skip the whole module:
+
+.. code-block:: python
+
+    @pytest.mark.skipif(sys.platform == 'win32', reason="does not run on windows")
+    class TestClass():
+        def test_feature_x(self):
+
+More details, example and ways are `here <https://docs.pytest.org/en/latest/skipping.html>`__.
+
+Custom markers
+~~~~~~~~~~~~~~
+
+* Slow tests
+
+Tests that are too slow (e.g. once downloading huge model files) are marked with:
+
+.. code-block:: python
+
+    from transformers.testing_utils import slow
+    @slow
+    def test_integration_foo():
+
+To run such tests set ``RUN_SLOW=1`` env var, e.g.:
+
+.. code-block:: bash
+
+    RUN_SLOW=1 pytest tests
+
+
+Testing the stdout/stderr output
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+In order to test functions that write to ``stdout`` and/or ``stderr``,
+the test can access those streams using the ``pytest``'s `capsys
+system <https://docs.pytest.org/en/latest/capture.html>`__. Here is how
+this is accomplished:
+
+.. code-block:: python
+
+    import sys
+    def print_to_stdout(s): print(s)
+    def print_to_stderr(s): sys.stderr.write(s)
+    def test_result_and_stdout(capsys):
+        msg = "Hello"
+        print_to_stdout(msg)
+        print_to_stderr(msg)
+        out, err = capsys.readouterr() # consume the captured output streams
+        # optional: if you want to replay the consumed streams:
+        sys.stdout.write(out)
+        sys.stderr.write(err)
+        # test:
+        assert msg in out
+        assert msg in err
+
+And, of course, most of the time, ``stderr`` will come as a part of an
+exception, so try/except has to be used in such a case:
+
+.. code-block:: python
+
+    def raise_exception(msg): raise ValueError(msg)
+    def test_something_exception():
+        msg = "Not a good value"
+        error = ''
+        try:
+            raise_exception(msg)
+        except Exception as e:
+            error = str(e)
+            assert msg in error, f"{msg} is in the exception:\n{error}"
+
+Another approach to capturing stdout is via ``contextlib.redirect_stdout``:
+
+.. code-block:: python
+
+    from io import StringIO
+    from contextlib import redirect_stdout
+    def print_to_stdout(s): print(s)
+    def test_result_and_stdout():
+        msg = "Hello"
+        buffer = StringIO()
+        with redirect_stdout(buffer):
+            print_to_stdout(msg)
+        out = buffer.getvalue()
+        # optional: if you want to replay the consumed streams:
+        sys.stdout.write(out)
+        # test:
+        assert msg in out
+
+An important potential issue with capturing stdout is that it may
+contain ``\r`` characters that in normal ``print`` reset everything that
+has been printed so far. There is no problem with ``pytest``, but with
+``pytest -s`` these characters get included in the buffer, so to be able
+to have the test run with and without ``-s``, you have to make an extra
+cleanup to the captured output, using ``re.sub(r'~.*\r', '', buf, 0, re.M)``.
+
+But, then we have a helper context manager wrapper to automatically take
+care of it all, regardless of whether it has some ``\r``'s in it or
+not, so it's a simple:
+
+.. code-block:: python
+
+    from transformers.testing_utils import CaptureStdout
+    with CaptureStdout() as cs:
+        function_that_writes_to_stdout()
+    print(cs.out)
+
+Here is a full test example:
+
+.. code-block:: python
+
+    from transformers.testing_utils import CaptureStdout
+    msg = "Secret message\r"
+    final = "Hello World"
+    with CaptureStdout() as cs:
+        print(msg + final)
+    assert cs.out == final+"\n", f"captured: {cs.out}, expecting {final}"
+
+If you'd like to capture ``stderr`` use the :obj:`CaptureStderr` class
+instead:
+
+.. code-block:: python
+
+    from transformers.testing_utils import CaptureStderr
+    with CaptureStderr() as cs:
+        function_that_writes_to_stderr()
+    print(cs.err)
+
+If you need to capture both streams at once, use the parent
+:obj:`CaptureStd` class:
+
+.. code-block:: python
+
+    from transformers.testing_utils import CaptureStd
+    with CaptureStd() as cs:
+        function_that_writes_to_stdout_and_stderr()
+    print(cs.err, cs.out)
+
+
+
+Capturing logger stream
+~~~~~~~~~~~~~~~~~~~~~~~
+
+If you need to validate the output of a logger, you can use :obj:`CaptureLogger`:
+
+.. code-block:: python
+
+    from transformers import logging
+    from transformers.testing_utils import CaptureLogger
+
+    msg = "Testing 1, 2, 3"
+    logging.set_verbosity_info()
+    logger = logging.get_logger("transformers.tokenization_bart")
+    with CaptureLogger(logger) as cl:
+        logger.info(msg)
+    assert cl.out, msg+"\n"
+
+
+Testing with environment variables
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+If you want to test the impact of environment variables for a specific test you can use a helper decorator ``transformers.testing_utils.mockenv``
+
+.. code-block:: python
+
+    from transformers.testing_utils import mockenv
+    class HfArgumentParserTest(unittest.TestCase):
+        @mockenv(TRANSFORMERS_VERBOSITY="error")
+        def test_env_override(self):
+            env_level_str = os.getenv("TRANSFORMERS_VERBOSITY", None)
+
+
+Getting reproducible results
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+In some situations you may want to remove randomness for your tests. To
+get identical reproducable results set, you will need to fix the seed:
+
+.. code-block:: python
+
+    seed = 42
+
+    # python RNG
+    import random
+    random.seed(seed)
+
+    # pytorch RNGs
+    import torch
+    torch.manual_seed(seed)
+    torch.backends.cudnn.deterministic = True
+    if torch.cuda.is_available(): torch.cuda.manual_seed_all(seed)
+
+    # numpy RNG
+    import numpy as np
+    np.random.seed(seed)
+
+    # tf RNG
+    tf.random.set_seed(seed)
+
+Debugging tests
+~~~~~~~~~~~~~~~
+
+To start a debugger at the point of the warning, do this:
+
+.. code-block:: bash
+
+    pytest tests/test_logging.py -W error::UserWarning --pdb

docs/source/tokenizer_summary.rst

@@ -130,7 +130,7 @@ Then the base vocabulary is ['b', 'g', 'h', 'n', 'p', 's', 'u'] and all our word
 
 We then take each pair of symbols and look at the most frequent. For instance 'hu' is present `10 + 5 = 15` times (10
 times in the 10 occurrences of 'hug', 5 times in the 5 occurrences of 'hugs'). The most frequent here is 'ug', present
-`10 + 5 + 2 + 5 = 22` times in total. So the first merge rule the tokenizer learns is to group all 'u' and 'g' together
+`10 + 5 + 5 = 20` times in total. So the first merge rule the tokenizer learns is to group all 'u' and 'g' together
 then it adds 'ug' to the vocabulary. Our corpus then becomes
 
 ::

docs/source/training.rst

@@ -282,7 +282,7 @@ your own ``compute_metrics`` function and pass it to the trainer.
 
 .. code-block:: python
 
-    from sklearn.metrics import precision_recall_fscore_support
+    from sklearn.metrics import accuracy_score, precision_recall_fscore_support
 
     def compute_metrics(pred):
         labels = pred.label_ids