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modeling_tf_flaubert.py
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# coding=utf-8
# Copyright 2019-present, Facebook, Inc and the HuggingFace Inc. team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
TF 2.0 Flaubert model.
"""
import itertools
import random
import warnings
from dataclasses import dataclass
from typing import Optional, Tuple
import tensorflow as tf
from ...activations_tf import get_tf_activation
from ...file_utils import (
ModelOutput,
add_code_sample_docstrings,
add_start_docstrings,
add_start_docstrings_to_model_forward,
)
from ...modeling_tf_outputs import TFBaseModelOutput
from ...modeling_tf_utils import (
TFPreTrainedModel,
TFSharedEmbeddings,
get_initializer,
input_processing,
keras_serializable,
shape_list,
)
from ...utils import logging
from ..xlm.modeling_tf_xlm import (
TFXLMForMultipleChoice,
TFXLMForQuestionAnsweringSimple,
TFXLMForSequenceClassification,
TFXLMForTokenClassification,
)
from .configuration_flaubert import FlaubertConfig
logger = logging.get_logger(__name__)
_CHECKPOINT_FOR_DOC = "flaubert/flaubert_base_cased"
_CONFIG_FOR_DOC = "FlaubertConfig"
_TOKENIZER_FOR_DOC = "FlaubertTokenizer"
TF_FLAUBERT_PRETRAINED_MODEL_ARCHIVE_LIST = [
# See all Flaubert models at https://huggingface.co/models?filter=flaubert
]
FLAUBERT_START_DOCSTRING = r"""
This model inherits from :class:`~transformers.TFPreTrainedModel`. Check the superclass documentation for the
generic methods the library implements for all its model (such as downloading or saving, resizing the input
embeddings, pruning heads etc.)
This model is also a `tf.keras.Model <https://www.tensorflow.org/api_docs/python/tf/keras/Model>`__ subclass. Use
it as a regular TF 2.0 Keras Model and refer to the TF 2.0 documentation for all matter related to general usage
and behavior.
.. note::
TF 2.0 models accepts two formats as inputs:
- having all inputs as keyword arguments (like PyTorch models), or
- having all inputs as a list, tuple or dict in the first positional arguments.
This second option is useful when using :meth:`tf.keras.Model.fit` method which currently requires having all
the tensors in the first argument of the model call function: :obj:`model(inputs)`.
If you choose this second option, there are three possibilities you can use to gather all the input Tensors in
the first positional argument :
- a single Tensor with :obj:`input_ids` only and nothing else: :obj:`model(inputs_ids)`
- a list of varying length with one or several input Tensors IN THE ORDER given in the docstring:
:obj:`model([input_ids, attention_mask])` or :obj:`model([input_ids, attention_mask, token_type_ids])`
- a dictionary with one or several input Tensors associated to the input names given in the docstring:
:obj:`model({"input_ids": input_ids, "token_type_ids": token_type_ids})`
Parameters:
config (:class:`~transformers.FlaubertConfig`): Model configuration class with all the parameters of the model.
Initializing with a config file does not load the weights associated with the model, only the
configuration. Check out the :meth:`~transformers.PreTrainedModel.from_pretrained` method to load the model
weights.
"""
FLAUBERT_INPUTS_DOCSTRING = r"""
Args:
input_ids (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length)`):
Indices of input sequence tokens in the vocabulary.
Indices can be obtained using :class:`~transformers.FlaubertTokenizer`. See
:func:`transformers.PreTrainedTokenizer.__call__` and :func:`transformers.PreTrainedTokenizer.encode` for
details.
`What are input IDs? <../glossary.html#input-ids>`__
attention_mask (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length)`, `optional`):
Mask to avoid performing attention on padding token indices. Mask values selected in ``[0, 1]``:
- ``1`` for tokens that are **not masked**,
- ``0`` for tokens that are **masked**.
`What are attention masks? <../glossary.html#attention-mask>`__
langs (:obj:`tf.Tensor` or :obj:`Numpy array` of shape :obj:`(batch_size, sequence_length)`, `optional`):
A parallel sequence of tokens to be used to indicate the language of each token in the input. Indices are
languages ids which can be obtained from the language names by using two conversion mappings provided in
the configuration of the model (only provided for multilingual models). More precisely, the `language name
to language id` mapping is in :obj:`model.config.lang2id` (which is a dictionary string to int) and the
`language id to language name` mapping is in :obj:`model.config.id2lang` (dictionary int to string).
See usage examples detailed in the :doc:`multilingual documentation <../multilingual>`.
token_type_ids (:obj:`tf.Tensor` or :obj:`Numpy array` of shape :obj:`(batch_size, sequence_length)`, `optional`):
Segment token indices to indicate first and second portions of the inputs. Indices are selected in ``[0,
1]``:
- ``0`` corresponds to a `sentence A` token,
- ``1`` corresponds to a `sentence B` token.
`What are token type IDs? <../glossary.html#token-type-ids>`__
position_ids (:obj:`tf.Tensor` or :obj:`Numpy array` of shape :obj:`(batch_size, sequence_length)`, `optional`):
Indices of positions of each input sequence tokens in the position embeddings. Selected in the range ``[0,
config.max_position_embeddings - 1]``.
`What are position IDs? <../glossary.html#position-ids>`__
lengths (:obj:`tf.Tensor` or :obj:`Numpy array` of shape :obj:`(batch_size,)`, `optional`):
Length of each sentence that can be used to avoid performing attention on padding token indices. You can
also use `attention_mask` for the same result (see above), kept here for compatibility Indices selected in
``[0, ..., input_ids.size(-1)]``:
cache (:obj:`Dict[str, tf.Tensor]`, `optional`):
Dictionary string to ``tf.FloatTensor`` that contains precomputed hidden states (key and values in the
attention blocks) as computed by the model (see :obj:`cache` output below). Can be used to speed up
sequential decoding.
The dictionary object will be modified in-place during the forward pass to add newly computed
hidden-states.
head_mask (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`(num_heads,)` or :obj:`(num_layers, num_heads)`, `optional`):
Mask to nullify selected heads of the self-attention modules. Mask values selected in ``[0, 1]``:
- ``1`` indicates the head is **not masked**,
- ``0`` indicates the head is **masked**.
inputs_embeds (:obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length, hidden_size)`, `optional`):
Optionally, instead of passing :obj:`input_ids` you can choose to directly pass an embedded representation.
This is useful if you want more control over how to convert :obj:`input_ids` indices into associated
vectors than the model's internal embedding lookup matrix.
output_attentions (:obj:`bool`, `optional`):
Whether or not to return the attentions tensors of all attention layers. See ``attentions`` under returned
tensors for more detail. This argument can be used only in eager mode, in graph mode the value in the
config will be used instead.
output_hidden_states (:obj:`bool`, `optional`):
Whether or not to return the hidden states of all layers. See ``hidden_states`` under returned tensors for
more detail. This argument can be used only in eager mode, in graph mode the value in the config will be
used instead.
return_dict (:obj:`bool`, `optional`):
Whether or not to return a :class:`~transformers.file_utils.ModelOutput` instead of a plain tuple. This
argument can be used in eager mode, in graph mode the value will always be set to True.
training (:obj:`bool`, `optional`, defaults to :obj:`False`):
Whether or not to use the model in training mode (some modules like dropout modules have different
behaviors between training and evaluation).
"""
def get_masks(slen, lengths, causal, padding_mask=None):
"""
Generate hidden states mask, and optionally an attention mask.
"""
bs = shape_list(lengths)[0]
if padding_mask is not None:
mask = padding_mask
else:
# assert lengths.max().item() <= slen
alen = tf.range(slen)
mask = tf.math.less(alen, tf.expand_dims(lengths, axis=1))
# attention mask is the same as mask, or triangular inferior attention (causal)
if causal:
attn_mask = tf.less_equal(
tf.tile(tf.reshape(alen, (1, 1, slen)), (bs, slen, 1)), tf.reshape(alen, (1, slen, 1))
)
else:
attn_mask = mask
# sanity check
# assert shape_list(mask) == [bs, slen]
if tf.executing_eagerly():
tf.debugging.assert_equal(shape_list(mask), [bs, slen])
assert causal is False or shape_list(attn_mask) == [bs, slen, slen]
return mask, attn_mask
class TFFlaubertPreTrainedModel(TFPreTrainedModel):
"""
An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained
models.
"""
config_class = FlaubertConfig
base_model_prefix = "transformer"
@property
def dummy_inputs(self):
# Sometimes XLM has language embeddings so don't forget to build them as well if needed
inputs_list = tf.constant([[7, 6, 0, 0, 1], [1, 2, 3, 0, 0], [0, 0, 0, 4, 5]])
attns_list = tf.constant([[1, 1, 0, 0, 1], [1, 1, 1, 0, 0], [1, 0, 0, 1, 1]])
if self.config.use_lang_emb and self.config.n_langs > 1:
return {
"input_ids": inputs_list,
"attention_mask": attns_list,
"langs": tf.constant([[1, 1, 0, 0, 1], [1, 1, 1, 0, 0], [1, 0, 0, 1, 1]]),
}
else:
return {"input_ids": inputs_list, "attention_mask": attns_list}
@add_start_docstrings(
"The bare Flaubert Model transformer outputting raw hidden-states without any specific head on top.",
FLAUBERT_START_DOCSTRING,
)
class TFFlaubertModel(TFFlaubertPreTrainedModel):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.transformer = TFFlaubertMainLayer(config, name="transformer")
@add_start_docstrings_to_model_forward(FLAUBERT_INPUTS_DOCSTRING)
@add_code_sample_docstrings(
tokenizer_class=_TOKENIZER_FOR_DOC,
checkpoint=_CHECKPOINT_FOR_DOC,
output_type=TFBaseModelOutput,
config_class=_CONFIG_FOR_DOC,
)
def call(
self,
input_ids=None,
attention_mask=None,
langs=None,
token_type_ids=None,
position_ids=None,
lengths=None,
cache=None,
head_mask=None,
inputs_embeds=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
training=False,
**kwargs,
):
inputs = input_processing(
func=self.call,
config=self.config,
input_ids=input_ids,
attention_mask=attention_mask,
langs=langs,
token_type_ids=token_type_ids,
position_ids=position_ids,
lengths=lengths,
cache=cache,
head_mask=head_mask,
inputs_embeds=inputs_embeds,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
training=training,
kwargs_call=kwargs,
)
outputs = self.transformer(
input_ids=inputs["input_ids"],
attention_mask=inputs["attention_mask"],
langs=inputs["langs"],
token_type_ids=inputs["token_type_ids"],
position_ids=inputs["position_ids"],
lengths=inputs["lengths"],
cache=inputs["cache"],
head_mask=inputs["head_mask"],
inputs_embeds=inputs["inputs_embeds"],
output_attentions=inputs["output_attentions"],
output_hidden_states=inputs["output_hidden_states"],
return_dict=inputs["return_dict"],
training=inputs["training"],
)
return outputs
# Copied from transformers.models.distilbert.modeling_tf_distilbert.TFDistilBertModel.serving_output
def serving_output(self, output):
hs = tf.convert_to_tensor(output.hidden_states) if self.config.output_hidden_states else None
attns = tf.convert_to_tensor(output.attentions) if self.config.output_attentions else None
return TFBaseModelOutput(last_hidden_state=output.last_hidden_state, hidden_states=hs, attentions=attns)
# Copied from transformers.models.xlm.modeling_tf_xlm.TFXLMMultiHeadAttention with XLM->Flaubert
class TFFlaubertMultiHeadAttention(tf.keras.layers.Layer):
NEW_ID = itertools.count()
def __init__(self, n_heads, dim, config, **kwargs):
super().__init__(**kwargs)
self.layer_id = next(TFFlaubertMultiHeadAttention.NEW_ID)
self.dim = dim
self.n_heads = n_heads
self.output_attentions = config.output_attentions
assert self.dim % self.n_heads == 0
self.q_lin = tf.keras.layers.Dense(dim, kernel_initializer=get_initializer(config.init_std), name="q_lin")
self.k_lin = tf.keras.layers.Dense(dim, kernel_initializer=get_initializer(config.init_std), name="k_lin")
self.v_lin = tf.keras.layers.Dense(dim, kernel_initializer=get_initializer(config.init_std), name="v_lin")
self.out_lin = tf.keras.layers.Dense(dim, kernel_initializer=get_initializer(config.init_std), name="out_lin")
self.dropout = tf.keras.layers.Dropout(config.attention_dropout)
self.pruned_heads = set()
def prune_heads(self, heads):
raise NotImplementedError
def call(self, input, mask, kv, cache, head_mask, output_attentions, training=False):
"""
Self-attention (if kv is None) or attention over source sentence (provided by kv).
"""
# Input is (bs, qlen, dim)
# Mask is (bs, klen) (non-causal) or (bs, klen, klen)
bs, qlen, dim = shape_list(input)
if kv is None:
klen = qlen if cache is None else cache["slen"] + qlen
else:
klen = shape_list(kv)[1]
# assert dim == self.dim, 'Dimensions do not match: %s input vs %s configured' % (dim, self.dim)
dim_per_head = self.dim // self.n_heads
mask_reshape = (bs, 1, qlen, klen) if len(shape_list(mask)) == 3 else (bs, 1, 1, klen)
def shape(x):
""" projection """
return tf.transpose(tf.reshape(x, (bs, -1, self.n_heads, dim_per_head)), perm=(0, 2, 1, 3))
def unshape(x):
""" compute context """
return tf.reshape(tf.transpose(x, perm=(0, 2, 1, 3)), (bs, -1, self.n_heads * dim_per_head))
q = shape(self.q_lin(input)) # (bs, n_heads, qlen, dim_per_head)
if kv is None:
k = shape(self.k_lin(input)) # (bs, n_heads, qlen, dim_per_head)
v = shape(self.v_lin(input)) # (bs, n_heads, qlen, dim_per_head)
elif cache is None or self.layer_id not in cache:
k = v = kv
k = shape(self.k_lin(k)) # (bs, n_heads, qlen, dim_per_head)
v = shape(self.v_lin(v)) # (bs, n_heads, qlen, dim_per_head)
if cache is not None:
if self.layer_id in cache:
if kv is None:
k_, v_ = cache[self.layer_id]
k = tf.concat([k_, k], axis=2) # (bs, n_heads, klen, dim_per_head)
v = tf.concat([v_, v], axis=2) # (bs, n_heads, klen, dim_per_head)
else:
k, v = cache[self.layer_id]
cache[self.layer_id] = (k, v)
f_dim_per_head = tf.cast(dim_per_head, dtype=q.dtype)
q = tf.multiply(q, tf.math.rsqrt(f_dim_per_head)) # (bs, n_heads, qlen, dim_per_head)
k = tf.cast(k, dtype=q.dtype)
scores = tf.matmul(q, k, transpose_b=True) # (bs, n_heads, qlen, klen)
mask = tf.reshape(mask, mask_reshape) # (bs, n_heads, qlen, klen)
# scores.masked_fill_(mask, -float('inf')) # (bs, n_heads, qlen, klen)
mask = tf.cast(mask, dtype=scores.dtype)
scores = scores - 1e30 * (1.0 - mask)
weights = tf.nn.softmax(scores, axis=-1) # (bs, n_heads, qlen, klen)
weights = self.dropout(weights, training=training) # (bs, n_heads, qlen, klen)
# Mask heads if we want to
if head_mask is not None:
weights = weights * head_mask
context = tf.matmul(weights, v) # (bs, n_heads, qlen, dim_per_head)
context = unshape(context) # (bs, qlen, dim)
outputs = (self.out_lin(context),)
if output_attentions:
outputs = outputs + (weights,)
return outputs
# Copied from transformers.models.xlm.modeling_tf_xlm.TFXLMTransformerFFN
class TFFlaubertTransformerFFN(tf.keras.layers.Layer):
def __init__(self, in_dim, dim_hidden, out_dim, config, **kwargs):
super().__init__(**kwargs)
self.lin1 = tf.keras.layers.Dense(dim_hidden, kernel_initializer=get_initializer(config.init_std), name="lin1")
self.lin2 = tf.keras.layers.Dense(out_dim, kernel_initializer=get_initializer(config.init_std), name="lin2")
self.act = get_tf_activation("gelu") if config.gelu_activation else get_tf_activation("relu")
self.dropout = tf.keras.layers.Dropout(config.dropout)
def call(self, input, training=False):
x = self.lin1(input)
x = self.act(x)
x = self.lin2(x)
x = self.dropout(x, training=training)
return x
@keras_serializable
class TFFlaubertMainLayer(tf.keras.layers.Layer):
config_class = FlaubertConfig
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.config = config
self.n_heads = config.n_heads
self.n_langs = config.n_langs
self.dim = config.emb_dim
self.hidden_dim = self.dim * 4
self.n_words = config.n_words
self.pad_index = config.pad_index
self.causal = config.causal
self.n_layers = config.n_layers
self.use_lang_emb = config.use_lang_emb
self.layerdrop = getattr(config, "layerdrop", 0.0)
self.pre_norm = getattr(config, "pre_norm", False)
self.output_attentions = config.output_attentions
self.output_hidden_states = config.output_hidden_states
self.return_dict = config.use_return_dict
self.max_position_embeddings = config.max_position_embeddings
self.embed_init_std = config.embed_init_std
self.dropout = tf.keras.layers.Dropout(config.dropout)
self.embeddings = TFSharedEmbeddings(
self.n_words, self.dim, initializer_range=config.embed_init_std, name="embeddings"
)
self.layer_norm_emb = tf.keras.layers.LayerNormalization(epsilon=config.layer_norm_eps, name="layer_norm_emb")
self.attentions = []
self.layer_norm1 = []
self.ffns = []
self.layer_norm2 = []
for i in range(self.n_layers):
self.attentions.append(
TFFlaubertMultiHeadAttention(self.n_heads, self.dim, config=config, name="attentions_._{}".format(i))
)
self.layer_norm1.append(
tf.keras.layers.LayerNormalization(epsilon=config.layer_norm_eps, name="layer_norm1_._{}".format(i))
)
# if self.is_decoder:
# self.layer_norm15.append(nn.LayerNorm(self.dim, eps=config.layer_norm_eps))
# self.encoder_attn.append(MultiHeadAttention(self.n_heads, self.dim, dropout=self.attention_dropout))
self.ffns.append(
TFFlaubertTransformerFFN(
self.dim, self.hidden_dim, self.dim, config=config, name="ffns_._{}".format(i)
)
)
self.layer_norm2.append(
tf.keras.layers.LayerNormalization(epsilon=config.layer_norm_eps, name="layer_norm2_._{}".format(i))
)
def build(self, input_shape):
with tf.name_scope("position_embeddings"):
self.position_embeddings = self.add_weight(
name="embeddings",
shape=[self.max_position_embeddings, self.dim],
initializer=get_initializer(self.embed_init_std),
)
if self.n_langs > 1 and self.use_lang_emb:
with tf.name_scope("lang_embeddings"):
self.lang_embeddings = self.add_weight(
name="embeddings",
shape=[self.n_langs, self.dim],
initializer=get_initializer(self.embed_init_std),
)
super().build(input_shape)
def get_input_embeddings(self):
return self.embeddings
def set_input_embeddings(self, value):
self.embeddings.weight = value
self.embeddings.vocab_size = shape_list(value)[0]
def call(
self,
input_ids=None,
attention_mask=None,
langs=None,
token_type_ids=None,
position_ids=None,
lengths=None,
cache=None,
head_mask=None,
inputs_embeds=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
training=False,
**kwargs,
):
# removed: src_enc=None, src_len=None
inputs = input_processing(
func=self.call,
config=self.config,
input_ids=input_ids,
attention_mask=attention_mask,
langs=langs,
token_type_ids=token_type_ids,
position_ids=position_ids,
lengths=lengths,
cache=cache,
head_mask=head_mask,
inputs_embeds=inputs_embeds,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
training=training,
kwargs_call=kwargs,
)
if inputs["input_ids"] is not None and inputs["inputs_embeds"] is not None:
raise ValueError("You cannot specify both input_ids and inputs_embeds at the same time")
elif inputs["input_ids"] is not None:
bs, slen = shape_list(inputs["input_ids"])
elif inputs["inputs_embeds"] is not None:
bs, slen = shape_list(inputs["inputs_embeds"])[:2]
else:
raise ValueError("You have to specify either input_ids or inputs_embeds")
if inputs["lengths"] is None:
if inputs["input_ids"] is not None:
inputs["lengths"] = tf.reduce_sum(
tf.cast(tf.not_equal(inputs["input_ids"], self.pad_index), dtype=inputs["input_ids"].dtype), axis=1
)
else:
inputs["lengths"] = tf.convert_to_tensor([slen] * bs)
# mask = input_ids != self.pad_index
# check inputs
# assert shape_list(lengths)[0] == bs
if tf.executing_eagerly():
tf.debugging.assert_equal(
shape_list(inputs["lengths"])[0], bs
), f"Expected batch size {shape_list(inputs['lengths'])[0]} and received batch size {bs} mismatched"
# assert lengths.max().item() <= slen
# input_ids = input_ids.transpose(0, 1) # batch size as dimension 0
# assert (src_enc is None) == (src_len is None)
# if src_enc is not None:
# assert self.is_decoder
# assert src_enc.size(0) == bs
# generate masks
mask, attn_mask = get_masks(slen, inputs["lengths"], self.causal, padding_mask=inputs["attention_mask"])
# if self.is_decoder and src_enc is not None:
# src_mask = torch.arange(src_len.max(), dtype=torch.long, device=lengths.device) < src_len[:, None]
# position_ids
if inputs["position_ids"] is None:
inputs["position_ids"] = tf.expand_dims(tf.range(slen), axis=0)
inputs["position_ids"] = tf.tile(inputs["position_ids"], (bs, 1))
if tf.executing_eagerly():
# assert shape_list(position_ids) == [bs, slen] # (slen, bs)
tf.debugging.assert_equal(
shape_list(inputs["position_ids"]), [bs, slen]
), f"Position id shape {shape_list(inputs['position_ids'])} and input shape {[bs, slen]} mismatched"
# position_ids = position_ids.transpose(0, 1)
# langs
if inputs["langs"] is not None and tf.executing_eagerly():
# assert shape_list(langs) == [bs, slen] # (slen, bs)
tf.debugging.assert_equal(
shape_list(inputs["langs"]), [bs, slen]
), f"Lang shape {shape_list(inputs['langs'])} and input shape {[bs, slen]} mismatched"
# langs = langs.transpose(0, 1)
# Prepare head mask if needed
# 1.0 in head_mask indicate we keep the head
# attention_probs has shape bsz x n_heads x N x N
# input head_mask has shape [num_heads] or [num_hidden_layers x num_heads]
# and head_mask is converted to shape [num_hidden_layers x batch x num_heads x qlen x klen]
if inputs["head_mask"] is not None:
raise NotImplementedError
else:
inputs["head_mask"] = [None] * self.n_layers
# do not recompute cached elements
if inputs["cache"] is not None and inputs["input_ids"] is not None:
_slen = slen - inputs["cache"]["slen"]
inputs["input_ids"] = inputs["input_ids"][:, -_slen:]
inputs["position_ids"] = inputs["position_ids"][:, -_slen:]
if inputs["langs"] is not None:
inputs["langs"] = inputs["langs"][:, -_slen:]
mask = mask[:, -_slen:]
attn_mask = attn_mask[:, -_slen:]
# embeddings
if inputs["inputs_embeds"] is None:
inputs["inputs_embeds"] = self.embeddings(inputs["input_ids"])
tensor = inputs["inputs_embeds"] + tf.gather(self.position_embeddings, inputs["position_ids"])
if inputs["langs"] is not None and self.use_lang_emb:
tensor = tensor + tf.gather(self.lang_embeddings, inputs["langs"])
if inputs["token_type_ids"] is not None:
tensor = tensor + self.embeddings(inputs["token_type_ids"])
tensor = self.layer_norm_emb(tensor)
tensor = self.dropout(tensor, training=inputs["training"])
mask = tf.cast(mask, dtype=tensor.dtype)
tensor = tensor * tf.expand_dims(mask, axis=-1)
# hidden_states and attentions cannot be None in graph mode.
hidden_states = () if inputs["output_hidden_states"] else None
attentions = () if inputs["output_attentions"] else None
# transformer layers
for i in range(self.n_layers):
# LayerDrop
dropout_probability = random.uniform(0, 1)
if inputs["training"] and (dropout_probability < self.layerdrop):
continue
if inputs["output_hidden_states"]:
hidden_states = hidden_states + (tensor,)
# self attention
if not self.pre_norm:
attn_outputs = self.attentions[i](
tensor,
attn_mask,
None,
inputs["cache"],
inputs["head_mask"][i],
inputs["output_attentions"],
training=inputs["training"],
)
attn = attn_outputs[0]
if inputs["output_attentions"]:
attentions = attentions + (attn_outputs[1],)
attn = self.dropout(attn, training=inputs["training"])
tensor = tensor + attn
tensor = self.layer_norm1[i](tensor)
else:
tensor_normalized = self.layer_norm1[i](tensor)
attn_outputs = self.attentions[i](
tensor_normalized,
attn_mask,
None,
inputs["cache"],
inputs["head_mask"][i],
inputs["output_attentions"],
training=inputs["training"],
)
attn = attn_outputs[0]
if inputs["output_attentions"]:
attentions = attentions + (attn_outputs[1],)
attn = self.dropout(attn, training=inputs["training"])
tensor = tensor + attn
# encoder attention (for decoder only)
# if self.is_decoder and src_enc is not None:
# attn = self.encoder_attn[i](tensor, src_mask, kv=src_enc, cache=cache)
# attn = F.dropout(attn, p=self.dropout, training=self.training)
# tensor = tensor + attn
# tensor = self.layer_norm15[i](tensor)
# FFN
if not self.pre_norm:
tensor = tensor + self.ffns[i](tensor)
tensor = self.layer_norm2[i](tensor)
else:
tensor_normalized = self.layer_norm2[i](tensor)
tensor = tensor + self.ffns[i](tensor_normalized)
tensor = tensor * tf.expand_dims(mask, axis=-1)
# Add last hidden state
if inputs["output_hidden_states"]:
hidden_states = hidden_states + (tensor,)
# update cache length
if inputs["cache"] is not None:
inputs["cache"]["slen"] += tensor.size(1)
# move back sequence length to dimension 0
# tensor = tensor.transpose(0, 1)
if not inputs["return_dict"]:
return tuple(v for v in [tensor, hidden_states, attentions] if v is not None)
return TFBaseModelOutput(last_hidden_state=tensor, hidden_states=hidden_states, attentions=attentions)
# Copied from transformers.models.xlm.modeling_tf_xlm.TFXLMPredLayer
class TFFlaubertPredLayer(tf.keras.layers.Layer):
"""
Prediction layer (cross_entropy or adaptive_softmax).
"""
def __init__(self, config, input_embeddings, **kwargs):
super().__init__(**kwargs)
self.asm = config.asm
self.n_words = config.n_words
self.pad_index = config.pad_index
if config.asm is False:
self.input_embeddings = input_embeddings
else:
raise NotImplementedError
# self.proj = nn.AdaptiveLogSoftmaxWithLoss(
# in_features=dim,
# n_classes=config.n_words,
# cutoffs=config.asm_cutoffs,
# div_value=config.asm_div_value,
# head_bias=True, # default is False
# )
def build(self, input_shape):
# The output weights are the same as the input embeddings, but there is an output-only bias for each token.
self.bias = self.add_weight(shape=(self.n_words,), initializer="zeros", trainable=True, name="bias")
super().build(input_shape)
def get_output_embeddings(self):
return self.input_embeddings
def set_output_embeddings(self, value):
self.input_embeddings.weight = value
self.input_embeddings.vocab_size = shape_list(value)[0]
def get_bias(self):
return {"bias": self.bias}
def set_bias(self, value):
self.bias = value["bias"]
self.vocab_size = shape_list(value["bias"])[0]
def call(self, hidden_states):
hidden_states = self.input_embeddings(hidden_states, mode="linear")
hidden_states = hidden_states + self.bias
return hidden_states
@dataclass
class TFFlaubertWithLMHeadModelOutput(ModelOutput):
"""
Base class for :class:`~transformers.TFFlaubertWithLMHeadModel` outputs.
Args:
logits (:obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length, config.vocab_size)`):
Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax).
hidden_states (:obj:`tuple(tf.Tensor)`, `optional`, returned when ``output_hidden_states=True`` is passed or when ``config.output_hidden_states=True``):
Tuple of :obj:`tf.Tensor` (one for the output of the embeddings + one for the output of each layer) of
shape :obj:`(batch_size, sequence_length, hidden_size)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs.
attentions (:obj:`tuple(tf.Tensor)`, `optional`, returned when ``output_attentions=True`` is passed or when ``config.output_attentions=True``):
Tuple of :obj:`tf.Tensor` (one for each layer) of shape :obj:`(batch_size, num_heads, sequence_length,
sequence_length)`.
Attentions weights after the attention softmax, used to compute the weighted average in the self-attention
heads.
"""
logits: tf.Tensor = None
hidden_states: Optional[Tuple[tf.Tensor]] = None
attentions: Optional[Tuple[tf.Tensor]] = None
@add_start_docstrings(
"""
The Flaubert Model transformer with a language modeling head on top (linear layer with weights tied to the input
embeddings).
""",
FLAUBERT_START_DOCSTRING,
)
class TFFlaubertWithLMHeadModel(TFFlaubertPreTrainedModel):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.transformer = TFFlaubertMainLayer(config, name="transformer")
self.pred_layer = TFFlaubertPredLayer(config, self.transformer.embeddings, name="pred_layer_._proj")
def get_lm_head(self):
return self.pred_layer
def get_prefix_bias_name(self):
warnings.warn("The method get_prefix_bias_name is deprecated. Please use `get_bias` instead.", FutureWarning)
return self.name + "/" + self.pred_layer.name
def prepare_inputs_for_generation(self, inputs, **kwargs):
mask_token_id = self.config.mask_token_id
lang_id = self.config.lang_id
effective_batch_size = inputs.shape[0]
mask_token = tf.fill((effective_batch_size, 1), 1) * mask_token_id
inputs = tf.concat([inputs, mask_token], axis=1)
if lang_id is not None:
langs = tf.ones_like(inputs) * lang_id
else:
langs = None
return {"input_ids": inputs, "langs": langs}
@add_start_docstrings_to_model_forward(FLAUBERT_INPUTS_DOCSTRING)
@add_code_sample_docstrings(
tokenizer_class=_TOKENIZER_FOR_DOC,
checkpoint=_CHECKPOINT_FOR_DOC,
output_type=TFFlaubertWithLMHeadModelOutput,
config_class=_CONFIG_FOR_DOC,
)
def call(
self,
input_ids=None,
attention_mask=None,
langs=None,
token_type_ids=None,
position_ids=None,
lengths=None,
cache=None,
head_mask=None,
inputs_embeds=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
training=False,
**kwargs,
):
inputs = input_processing(
func=self.call,
config=self.config,
input_ids=input_ids,
attention_mask=attention_mask,
langs=langs,
token_type_ids=token_type_ids,
position_ids=position_ids,
lengths=lengths,
cache=cache,
head_mask=head_mask,
inputs_embeds=inputs_embeds,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
training=training,
kwargs_call=kwargs,
)
transformer_outputs = self.transformer(
input_ids=inputs["input_ids"],
attention_mask=inputs["attention_mask"],
langs=inputs["langs"],
token_type_ids=inputs["token_type_ids"],
position_ids=inputs["position_ids"],
lengths=inputs["lengths"],
cache=inputs["cache"],
head_mask=inputs["head_mask"],
inputs_embeds=inputs["inputs_embeds"],
output_attentions=inputs["output_attentions"],
output_hidden_states=inputs["output_hidden_states"],
return_dict=inputs["return_dict"],
training=inputs["training"],
)
output = transformer_outputs[0]
outputs = self.pred_layer(output)
if not inputs["return_dict"]:
return (outputs,) + transformer_outputs[1:]
return TFFlaubertWithLMHeadModelOutput(
logits=outputs, hidden_states=transformer_outputs.hidden_states, attentions=transformer_outputs.attentions
)
def serving_output(self, output):
hs = tf.convert_to_tensor(output.hidden_states) if self.config.output_hidden_states else None
attns = tf.convert_to_tensor(output.attentions) if self.config.output_attentions else None
return TFFlaubertWithLMHeadModelOutput(logits=output.logits, hidden_states=hs, attentions=attns)
@add_start_docstrings(
"""
Flaubert Model with a sequence classification/regression head on top (a linear layer on top of the pooled output)
e.g. for GLUE tasks.
""",
FLAUBERT_START_DOCSTRING,
)
class TFFlaubertForSequenceClassification(TFXLMForSequenceClassification):
config_class = FlaubertConfig
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.transformer = TFFlaubertMainLayer(config, name="transformer")
@add_start_docstrings(
"""
Flaubert Model with a span classification head on top for extractive question-answering tasks like SQuAD (a linear
layer on top of the hidden-states output to compute `span start logits` and `span end logits`).
""",
FLAUBERT_START_DOCSTRING,
)
class TFFlaubertForQuestionAnsweringSimple(TFXLMForQuestionAnsweringSimple):
config_class = FlaubertConfig
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.transformer = TFFlaubertMainLayer(config, name="transformer")
@add_start_docstrings(
"""
Flaubert Model with a token classification head on top (a linear layer on top of the hidden-states output) e.g. for
Named-Entity-Recognition (NER) tasks.
""",
FLAUBERT_START_DOCSTRING,
)
class TFFlaubertForTokenClassification(TFXLMForTokenClassification):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.transformer = TFFlaubertMainLayer(config, name="transformer")
@add_start_docstrings(
"""
Flaubert Model with a multiple choice classification head on top (a linear layer on top of the pooled output and a
softmax) e.g. for RocStories/SWAG tasks.
""",
FLAUBERT_START_DOCSTRING,
)
class TFFlaubertForMultipleChoice(TFXLMForMultipleChoice):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.transformer = TFFlaubertMainLayer(config, name="transformer")

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