Update doc to new model outputs (#5946)

* Update doc to new model outputs

* Fix outputs in quicktour

docs/source/quicktour.rst

@@ -230,13 +230,18 @@ final activations of the model.
 
     >>> ## PYTORCH CODE
     >>> print(pt_outputs)
-    (tensor([[-4.0833,  4.3364],
-            [ 0.0818, -0.0418]], grad_fn=<AddmmBackward>),)
+    SequenceClassifierOutput(loss=None, logits=tensor([[-4.0833,  4.3364],
+            [ 0.0818, -0.0418]], grad_fn=<AddmmBackward>), hidden_states=None, attentions=None)
     >>> ## TENSORFLOW CODE
     >>> print(tf_outputs)
     (<tf.Tensor: shape=(2, 2), dtype=float32, numpy=
-    array([[-4.0832963 ,  4.3364134 ],
-           [ 0.08181238, -0.04178794]], dtype=float32)>,)
+    array([[-4.0832963 ,  4.336414  ],
+           [ 0.08181786, -0.04179301]], dtype=float32)>,)
+
+The model can return more than just the final activations, which is why the PyTorch output is a special class and the
+TensorFlow output is a tuple. Here we only asked for the final activations, so we get a tuple with one element on the
+TensorFlow side and a :class:`~transformers.modeling_outputs.SequenceClassifierOutput` with just the ``logits`` field
+filled on the PyTorch side.
 
 .. note::
 
@@ -249,7 +254,7 @@ Let's apply the SoftMax activation to get predictions.
 
     >>> ## PYTORCH CODE
     >>> import torch.nn.functional as F
-    >>> pt_predictions = F.softmax(pt_outputs[0], dim=-1)
+    >>> pt_predictions = F.softmax(pt_outputs.logits, dim=-1)
     >>> ## TENSORFLOW CODE
     >>> import tensorflow as tf
     >>> tf_predictions = tf.nn.softmax(tf_outputs[0], axis=-1)
@@ -262,7 +267,7 @@ We can see we get the numbers from before:
     >>> print(tf_predictions)
     tf.Tensor(
     [[2.2042994e-04 9.9977952e-01]
-     [5.3086078e-01 4.6913919e-01]], shape=(2, 2), dtype=float32)
+     [5.3086340e-01 4.6913657e-01]], shape=(2, 2), dtype=float32)
     >>> ## PYTORCH CODE
     >>> print(pt_predictions)
     tensor([[2.2043e-04, 9.9978e-01],
@@ -285,6 +290,12 @@ training loop. 🤗 Transformers also provides a :class:`~transformers.Trainer`
 you are using TensorFlow) class to help with your training (taking care of things such as distributed training, mixed
 precision, etc.). See the :doc:`training tutorial <training>` for more details.
 
+.. note::
+
+    Pytorch model outputs are special dataclasses so that you can get autocompletion for their attributes in an IDE.
+    They also behave like a tuple or a dictionary (e.g., you can index with an integer, a slice or a string) in which
+    case the attributes not set (that have :obj:`None` values) are ignored.
+
 Once your model is fine-tuned, you can save it with its tokenizer in the following way:
 
 ::

docs/source/task_summary.rst

@@ -98,8 +98,8 @@ of each other. The process is the following:
     >>> paraphrase = tokenizer(sequence_0, sequence_2, return_tensors="pt")
     >>> not_paraphrase = tokenizer(sequence_0, sequence_1, return_tensors="pt")
 
-    >>> paraphrase_classification_logits = model(**paraphrase)[0]
-    >>> not_paraphrase_classification_logits = model(**not_paraphrase)[0]
+    >>> paraphrase_classification_logits = model(**paraphrase).logits
+    >>> not_paraphrase_classification_logits = model(**not_paraphrase).logits
 
     >>> paraphrase_results = torch.softmax(paraphrase_classification_logits, dim=1).tolist()[0]
     >>> not_paraphrase_results = torch.softmax(not_paraphrase_classification_logits, dim=1).tolist()[0]
@@ -375,7 +375,7 @@ Here is an example doing masked language modeling using a model and a tokenizer.
     >>> input = tokenizer.encode(sequence, return_tensors="pt")
     >>> mask_token_index = torch.where(input == tokenizer.mask_token_id)[1]
 
-    >>> token_logits = model(input)[0]
+    >>> token_logits = model(input).logits
     >>> mask_token_logits = token_logits[0, mask_token_index, :]
 
     >>> top_5_tokens = torch.topk(mask_token_logits, 5, dim=1).indices[0].tolist()
@@ -436,7 +436,7 @@ Here is an example using the tokenizer and model and leveraging the :func:`~tran
     >>> input_ids = tokenizer.encode(sequence, return_tensors="pt")
 
     >>> # get logits of last hidden state
-    >>> next_token_logits = model(input_ids)[0][:, -1, :]
+    >>> next_token_logits = model(input_ids).logits[:, -1, :]
 
     >>> # filter
     >>> filtered_next_token_logits = top_k_top_p_filtering(next_token_logits, top_k=50, top_p=1.0)
@@ -666,7 +666,7 @@ Here is an example doing named entity recognition using a model and a tokenizer.
     >>> tokens = tokenizer.tokenize(tokenizer.decode(tokenizer.encode(sequence)))
     >>> inputs = tokenizer.encode(sequence, return_tensors="pt")
 
-    >>> outputs = model(inputs)[0]
+    >>> outputs = model(inputs).logits
     >>> predictions = torch.argmax(outputs, dim=2)
     >>> ## TENSORFLOW CODE
     >>> from transformers import TFAutoModelForTokenClassification, AutoTokenizer

docs/source/training.rst

@@ -99,7 +99,7 @@ backwards pass and update the weights:
 
     labels = torch.tensor([1,0]).unsqueeze(0)
     outputs = model(input_ids, attention_mask=attention_mask, labels=labels)
-    loss = outputs[0]
+    loss = outputs.loss
     loss.backward()
     optimizer.step()
 
@@ -111,7 +111,7 @@ The following is equivalent to the previous example:
     from torch.nn import functional as F
     labels = torch.tensor([1,0]).unsqueeze(0)
     outputs = model(input_ids, attention_mask=attention_mask)
-    loss = F.cross_entropy(labels, outputs[0])
+    loss = F.cross_entropy(labels, outputs.logitd)
     loss.backward()
     optimizer.step()