# coding=utf-8
# Copyright 2018 The Google AI Language Team Authors and The HuggingFace Inc. team.
# Copyright (c) 2018, NVIDIA CORPORATION. All rights reserved.
#
# 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 MobileBERT model. """
import logging
import tensorflow as tf
from . import MobileBertConfig
from .file_utils import (
MULTIPLE_CHOICE_DUMMY_INPUTS,
add_code_sample_docstrings,
add_start_docstrings,
add_start_docstrings_to_callable,
)
from .modeling_tf_bert import TFBertIntermediate, gelu, gelu_new, swish
from .modeling_tf_utils import (
TFMultipleChoiceLoss,
TFPreTrainedModel,
TFQuestionAnsweringLoss,
TFSequenceClassificationLoss,
TFTokenClassificationLoss,
cast_bool_to_primitive,
get_initializer,
keras_serializable,
shape_list,
)
from .tokenization_utils import BatchEncoding
logger = logging.getLogger(__name__)
_TOKENIZER_FOR_DOC = "MobileBertTokenizer"
TF_MOBILEBERT_PRETRAINED_MODEL_ARCHIVE_LIST = [
"mobilebert-uncased",
# See all MobileBERT models at https://huggingface.co/models?filter=mobilebert
]
def mish(x):
return x * tf.tanh(tf.math.softplus(x))
class TFLayerNorm(tf.keras.layers.LayerNormalization):
def __init__(self, feat_size, *args, **kwargs):
super().__init__(*args, **kwargs)
class TFNoNorm(tf.keras.layers.Layer):
def __init__(self, feat_size, epsilon=None, **kwargs):
super().__init__(**kwargs)
self.feat_size = feat_size
def build(self, input_shape):
self.bias = self.add_weight("bias", shape=[self.feat_size], initializer="zeros")
self.weight = self.add_weight("weight", shape=[self.feat_size], initializer="ones")
def call(self, inputs: tf.Tensor):
return inputs * self.weight + self.bias
ACT2FN = {
"gelu": tf.keras.layers.Activation(gelu),
"relu": tf.keras.activations.relu,
"swish": tf.keras.layers.Activation(swish),
"gelu_new": tf.keras.layers.Activation(gelu_new),
}
NORM2FN = {"layer_norm": TFLayerNorm, "no_norm": TFNoNorm}
class TFMobileBertEmbeddings(tf.keras.layers.Layer):
"""Construct the embeddings from word, position and token_type embeddings.
"""
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.trigram_input = config.trigram_input
self.embedding_size = config.embedding_size
self.vocab_size = config.vocab_size
self.hidden_size = config.hidden_size
self.initializer_range = config.initializer_range
self.position_embeddings = tf.keras.layers.Embedding(
config.max_position_embeddings,
config.hidden_size,
embeddings_initializer=get_initializer(self.initializer_range),
name="position_embeddings",
)
self.token_type_embeddings = tf.keras.layers.Embedding(
config.type_vocab_size,
config.hidden_size,
embeddings_initializer=get_initializer(self.initializer_range),
name="token_type_embeddings",
)
self.embedding_transformation = tf.keras.layers.Dense(config.hidden_size, name="embedding_transformation")
# self.LayerNorm is not snake-cased to stick with TensorFlow model variable name and be able to load
# any TensorFlow checkpoint file
self.LayerNorm = NORM2FN[config.normalization_type](
config.hidden_size, epsilon=config.layer_norm_eps, name="LayerNorm"
)
self.dropout = tf.keras.layers.Dropout(config.hidden_dropout_prob)
def build(self, input_shape):
"""Build shared word embedding layer """
with tf.name_scope("word_embeddings"):
# Create and initialize weights. The random normal initializer was chosen
# arbitrarily, and works well.
self.word_embeddings = self.add_weight(
"weight",
shape=[self.vocab_size, self.embedding_size],
initializer=get_initializer(self.initializer_range),
)
super().build(input_shape)
def call(self, inputs, mode="embedding", training=False):
"""Get token embeddings of inputs.
Args:
inputs: list of three int64 tensors with shape [batch_size, length]: (input_ids, position_ids, token_type_ids)
mode: string, a valid value is one of "embedding" and "linear".
Returns:
outputs: (1) If mode == "embedding", output embedding tensor, float32 with
shape [batch_size, length, embedding_size]; (2) mode == "linear", output
linear tensor, float32 with shape [batch_size, length, vocab_size].
Raises:
ValueError: if mode is not valid.
Shared weights logic adapted from
https://github.com/tensorflow/models/blob/a009f4fb9d2fc4949e32192a944688925ef78659/official/transformer/v2/embedding_layer.py#L24
"""
if mode == "embedding":
return self._embedding(inputs, training=training)
elif mode == "linear":
return self._linear(inputs)
else:
raise ValueError("mode {} is not valid.".format(mode))
def _embedding(self, inputs, training=False):
"""Applies embedding based on inputs tensor."""
input_ids, position_ids, token_type_ids, inputs_embeds = inputs
if input_ids is not None:
input_shape = shape_list(input_ids)
else:
input_shape = shape_list(inputs_embeds)[:-1]
seq_length = input_shape[1]
if position_ids is None:
position_ids = tf.range(seq_length, dtype=tf.int32)[tf.newaxis, :]
if token_type_ids is None:
token_type_ids = tf.fill(input_shape, 0)
if inputs_embeds is None:
inputs_embeds = tf.gather(self.word_embeddings, input_ids)
if self.trigram_input:
# From the paper MobileBERT: a Compact Task-Agnostic BERT for Resource-Limited
# Devices (https://arxiv.org/abs/2004.02984)
#
# The embedding table in BERT models accounts for a substantial proportion of model size. To compress
# the embedding layer, we reduce the embedding dimension to 128 in MobileBERT.
# Then, we apply a 1D convolution with kernel size 3 on the raw token embedding to produce a 512
# dimensional output.
inputs_embeds = tf.concat(
[
tf.pad(inputs_embeds[:, 1:], ((0, 0), (0, 1), (0, 0))),
inputs_embeds,
tf.pad(inputs_embeds[:, :-1], ((0, 0), (1, 0), (0, 0))),
],
axis=2,
)
if self.trigram_input or self.embedding_size != self.hidden_size:
inputs_embeds = self.embedding_transformation(inputs_embeds)
position_embeddings = self.position_embeddings(position_ids)
token_type_embeddings = self.token_type_embeddings(token_type_ids)
embeddings = inputs_embeds + position_embeddings + token_type_embeddings
embeddings = self.LayerNorm(embeddings)
embeddings = self.dropout(embeddings, training=training)
return embeddings
def _linear(self, inputs):
"""Computes logits by running inputs through a linear layer.
Args:
inputs: A float32 tensor with shape [batch_size, length, hidden_size]
Returns:
float32 tensor with shape [batch_size, length, vocab_size].
"""
batch_size = shape_list(inputs)[0]
length = shape_list(inputs)[1]
x = tf.reshape(inputs, [-1, self.hidden_size])
logits = tf.matmul(x, self.word_embeddings, transpose_b=True)
return tf.reshape(logits, [batch_size, length, self.vocab_size])
class TFMobileBertSelfAttention(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
if config.hidden_size % config.num_attention_heads != 0:
raise ValueError(
"The hidden size (%d) is not a multiple of the number of attention "
"heads (%d)" % (config.hidden_size, config.num_attention_heads)
)
self.num_attention_heads = config.num_attention_heads
assert config.hidden_size % config.num_attention_heads == 0
self.attention_head_size = int(config.true_hidden_size / config.num_attention_heads)
self.all_head_size = self.num_attention_heads * self.attention_head_size
self.query = tf.keras.layers.Dense(
self.all_head_size, kernel_initializer=get_initializer(config.initializer_range), name="query"
)
self.key = tf.keras.layers.Dense(
self.all_head_size, kernel_initializer=get_initializer(config.initializer_range), name="key"
)
self.value = tf.keras.layers.Dense(
self.all_head_size, kernel_initializer=get_initializer(config.initializer_range), name="value"
)
self.dropout = tf.keras.layers.Dropout(config.attention_probs_dropout_prob)
def transpose_for_scores(self, x, batch_size):
x = tf.reshape(x, (batch_size, -1, self.num_attention_heads, self.attention_head_size))
return tf.transpose(x, perm=[0, 2, 1, 3])
def call(self, inputs, training=False):
query_tensor, key_tensor, value_tensor, attention_mask, head_mask, output_attentions = inputs
batch_size = shape_list(attention_mask)[0]
mixed_query_layer = self.query(query_tensor)
mixed_key_layer = self.key(key_tensor)
mixed_value_layer = self.value(value_tensor)
query_layer = self.transpose_for_scores(mixed_query_layer, batch_size)
key_layer = self.transpose_for_scores(mixed_key_layer, batch_size)
value_layer = self.transpose_for_scores(mixed_value_layer, batch_size)
# Take the dot product between "query" and "key" to get the raw attention scores.
attention_scores = tf.matmul(
query_layer, key_layer, transpose_b=True
) # (batch size, num_heads, seq_len_q, seq_len_k)
dk = tf.cast(shape_list(key_layer)[-1], tf.float32) # scale attention_scores
attention_scores = attention_scores / tf.math.sqrt(dk)
if attention_mask is not None:
# Apply the attention mask is (precomputed for all layers in TFBertModel call() function)
attention_scores = attention_scores + attention_mask
# Normalize the attention scores to probabilities.
attention_probs = tf.nn.softmax(attention_scores, axis=-1)
# This is actually dropping out entire tokens to attend to, which might
# seem a bit unusual, but is taken from the original Transformer paper.
attention_probs = self.dropout(attention_probs, training=training)
# Mask heads if we want to
if head_mask is not None:
attention_probs = attention_probs * head_mask
context_layer = tf.matmul(attention_probs, value_layer)
context_layer = tf.transpose(context_layer, perm=[0, 2, 1, 3])
context_layer = tf.reshape(
context_layer, (batch_size, -1, self.all_head_size)
) # (batch_size, seq_len_q, all_head_size)
outputs = (
(context_layer, attention_probs) if cast_bool_to_primitive(output_attentions) is True else (context_layer,)
)
return outputs
class TFMobileBertSelfOutput(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.use_bottleneck = config.use_bottleneck
self.dense = tf.keras.layers.Dense(
config.true_hidden_size, kernel_initializer=get_initializer(config.initializer_range), name="dense"
)
self.LayerNorm = NORM2FN[config.normalization_type](
config.true_hidden_size, epsilon=config.layer_norm_eps, name="LayerNorm"
)
if not self.use_bottleneck:
self.dropout = tf.keras.layers.Dropout(config.hidden_dropout_prob)
def call(self, inputs, training=False):
hidden_states, residual_tensor = inputs
hidden_states = self.dense(hidden_states)
if not self.use_bottleneck:
hidden_states = self.dropout(hidden_states, training=training)
hidden_states = self.LayerNorm(hidden_states + residual_tensor)
return hidden_states
class TFMobileBertAttention(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.self = TFMobileBertSelfAttention(config, name="self")
self.mobilebert_output = TFMobileBertSelfOutput(config, name="output")
def prune_heads(self, heads):
raise NotImplementedError
def call(self, inputs, training=False):
query_tensor, key_tensor, value_tensor, layer_input, attention_mask, head_mask, output_attentions = inputs
self_outputs = self.self(
[query_tensor, key_tensor, value_tensor, attention_mask, head_mask, output_attentions], training=training
)
attention_output = self.mobilebert_output([self_outputs[0], layer_input], training=training)
outputs = (attention_output,) + self_outputs[1:] # add attentions if we output them
return outputs
class TFMobileBertIntermediate(TFBertIntermediate):
def __init__(self, config, **kwargs):
super().__init__(config, **kwargs)
self.dense = tf.keras.layers.Dense(config.intermediate_size, name="dense")
class TFOutputBottleneck(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.dense = tf.keras.layers.Dense(config.hidden_size, name="dense")
self.LayerNorm = NORM2FN[config.normalization_type](
config.hidden_size, epsilon=config.layer_norm_eps, name="LayerNorm"
)
self.dropout = tf.keras.layers.Dropout(config.hidden_dropout_prob)
def call(self, inputs, training=False):
hidden_states, residual_tensor = inputs
layer_outputs = self.dense(hidden_states)
layer_outputs = self.dropout(layer_outputs, training=training)
layer_outputs = self.LayerNorm(layer_outputs + residual_tensor)
return layer_outputs
class TFMobileBertOutput(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.use_bottleneck = config.use_bottleneck
self.dense = tf.keras.layers.Dense(
config.true_hidden_size, kernel_initializer=get_initializer(config.initializer_range), name="dense"
)
self.LayerNorm = NORM2FN[config.normalization_type](
config.true_hidden_size, epsilon=config.layer_norm_eps, name="LayerNorm"
)
if not self.use_bottleneck:
self.dropout = tf.keras.layers.Dropout(config.hidden_dropout_prob)
else:
self.bottleneck = TFOutputBottleneck(config, name="bottleneck")
def call(self, inputs, training=False):
hidden_states, residual_tensor_1, residual_tensor_2 = inputs
hidden_states = self.dense(hidden_states)
if not self.use_bottleneck:
hidden_states = self.dropout(hidden_states, training=training)
hidden_states = self.LayerNorm(hidden_states + residual_tensor_1)
else:
hidden_states = self.LayerNorm(hidden_states + residual_tensor_1)
hidden_states = self.bottleneck([hidden_states, residual_tensor_2])
return hidden_states
class TFBottleneckLayer(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.dense = tf.keras.layers.Dense(config.intra_bottleneck_size, name="dense")
self.LayerNorm = NORM2FN[config.normalization_type](
config.intra_bottleneck_size, epsilon=config.layer_norm_eps, name="LayerNorm"
)
def call(self, inputs):
hidden_states = self.dense(inputs)
hidden_states = self.LayerNorm(hidden_states)
return hidden_states
class TFBottleneck(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.key_query_shared_bottleneck = config.key_query_shared_bottleneck
self.use_bottleneck_attention = config.use_bottleneck_attention
self.bottleneck_input = TFBottleneckLayer(config, name="input")
if self.key_query_shared_bottleneck:
self.attention = TFBottleneckLayer(config, name="attention")
def call(self, hidden_states):
# This method can return three different tuples of values. These different values make use of bottlenecks,
# which are linear layers used to project the hidden states to a lower-dimensional vector, reducing memory
# usage. These linear layer have weights that are learned during training.
#
# If `config.use_bottleneck_attention`, it will return the result of the bottleneck layer four times for the
# key, query, value, and "layer input" to be used by the attention layer.
# This bottleneck is used to project the hidden. This last layer input will be used as a residual tensor
# in the attention self output, after the attention scores have been computed.
#
# If not `config.use_bottleneck_attention` and `config.key_query_shared_bottleneck`, this will return
# four values, three of which have been passed through a bottleneck: the query and key, passed through the same
# bottleneck, and the residual layer to be applied in the attention self output, through another bottleneck.
#
# Finally, in the last case, the values for the query, key and values are the hidden states without bottleneck,
# and the residual layer will be this value passed through a bottleneck.
bottlenecked_hidden_states = self.bottleneck_input(hidden_states)
if self.use_bottleneck_attention:
return (bottlenecked_hidden_states,) * 4
elif self.key_query_shared_bottleneck:
shared_attention_input = self.attention(hidden_states)
return (shared_attention_input, shared_attention_input, hidden_states, bottlenecked_hidden_states)
else:
return (hidden_states, hidden_states, hidden_states, bottlenecked_hidden_states)
class TFFFNOutput(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.dense = tf.keras.layers.Dense(config.true_hidden_size, name="dense")
self.LayerNorm = NORM2FN[config.normalization_type](
config.true_hidden_size, epsilon=config.layer_norm_eps, name="LayerNorm"
)
def call(self, hidden_states, residual_tensor):
hidden_states = self.dense(hidden_states)
hidden_states = self.LayerNorm(hidden_states + residual_tensor)
return hidden_states
class TFFFNLayer(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.intermediate = TFMobileBertIntermediate(config, name="intermediate")
self.mobilebert_output = TFFFNOutput(config, name="output")
def call(self, hidden_states):
intermediate_output = self.intermediate(hidden_states)
layer_outputs = self.mobilebert_output(intermediate_output, hidden_states)
return layer_outputs
class TFMobileBertLayer(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.use_bottleneck = config.use_bottleneck
self.num_feedforward_networks = config.num_feedforward_networks
self.attention = TFMobileBertAttention(config, name="attention")
self.intermediate = TFMobileBertIntermediate(config, name="intermediate")
self.mobilebert_output = TFMobileBertOutput(config, name="output")
if self.use_bottleneck:
self.bottleneck = TFBottleneck(config, name="bottleneck")
if config.num_feedforward_networks > 1:
self.ffn = [
TFFFNLayer(config, name="ffn.{}".format(i)) for i in range(config.num_feedforward_networks - 1)
]
def call(self, inputs, training=False):
hidden_states, attention_mask, head_mask, output_attentions = inputs
if self.use_bottleneck:
query_tensor, key_tensor, value_tensor, layer_input = self.bottleneck(hidden_states)
else:
query_tensor, key_tensor, value_tensor, layer_input = [hidden_states] * 4
attention_outputs = self.attention(
[query_tensor, key_tensor, value_tensor, layer_input, attention_mask, head_mask, output_attentions],
training=training,
)
attention_output = attention_outputs[0]
s = (attention_output,)
if self.num_feedforward_networks != 1:
for i, ffn_module in enumerate(self.ffn):
attention_output = ffn_module(attention_output)
s += (attention_output,)
intermediate_output = self.intermediate(attention_output)
layer_output = self.mobilebert_output(
[intermediate_output, attention_output, hidden_states], training=training
)
outputs = (
(layer_output,)
+ attention_outputs[1:]
+ (0, query_tensor, key_tensor, value_tensor, layer_input, attention_output, intermediate_output)
+ s
) # add attentions if we output them
return outputs
class TFMobileBertEncoder(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.layer = [TFMobileBertLayer(config, name="layer_._{}".format(i)) for i in range(config.num_hidden_layers)]
def call(self, inputs, training=False):
hidden_states, attention_mask, head_mask, output_attentions, output_hidden_states = inputs
all_hidden_states = ()
all_attentions = ()
for i, layer_module in enumerate(self.layer):
if cast_bool_to_primitive(output_hidden_states) is True:
all_hidden_states = all_hidden_states + (hidden_states,)
layer_outputs = layer_module(
[hidden_states, attention_mask, head_mask[i], output_attentions], training=training
)
hidden_states = layer_outputs[0]
if cast_bool_to_primitive(output_attentions) is True:
all_attentions = all_attentions + (layer_outputs[1],)
# Add last layer
if cast_bool_to_primitive(output_hidden_states) is True:
all_hidden_states = all_hidden_states + (hidden_states,)
outputs = (hidden_states,)
if cast_bool_to_primitive(output_hidden_states) is True:
outputs = outputs + (all_hidden_states,)
if cast_bool_to_primitive(output_attentions) is True:
outputs = outputs + (all_attentions,)
return outputs # outputs, (hidden states), (attentions)
class TFMobileBertPooler(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.do_activate = config.classifier_activation
if self.do_activate:
self.dense = tf.keras.layers.Dense(
config.hidden_size,
kernel_initializer=get_initializer(config.initializer_range),
activation="tanh",
name="dense",
)
def call(self, hidden_states):
# We "pool" the model by simply taking the hidden state corresponding
# to the first token.
first_token_tensor = hidden_states[:, 0]
if not self.do_activate:
return first_token_tensor
else:
pooled_output = self.dense(first_token_tensor)
return pooled_output
class TFMobileBertPredictionHeadTransform(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.dense = tf.keras.layers.Dense(
config.hidden_size, kernel_initializer=get_initializer(config.initializer_range), name="dense"
)
if isinstance(config.hidden_act, str):
self.transform_act_fn = ACT2FN[config.hidden_act]
else:
self.transform_act_fn = config.hidden_act
self.LayerNorm = NORM2FN["layer_norm"](config.hidden_size, epsilon=config.layer_norm_eps, name="LayerNorm")
def call(self, hidden_states):
hidden_states = self.dense(hidden_states)
hidden_states = self.transform_act_fn(hidden_states)
hidden_states = self.LayerNorm(hidden_states)
return hidden_states
class TFMobileBertLMPredictionHead(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.transform = TFMobileBertPredictionHeadTransform(config, name="transform")
self.vocab_size = config.vocab_size
self.config = config
def build(self, input_shape):
self.bias = self.add_weight(shape=(self.vocab_size,), initializer="zeros", trainable=True, name="bias")
self.dense = self.add_weight(
shape=(self.config.hidden_size - self.config.embedding_size, self.vocab_size),
initializer="zeros",
trainable=True,
name="dense/weight",
)
self.decoder = self.add_weight(
shape=(self.config.vocab_size, self.config.embedding_size),
initializer="zeros",
trainable=True,
name="decoder/weight",
)
super().build(input_shape)
def call(self, hidden_states):
hidden_states = self.transform(hidden_states)
hidden_states = tf.matmul(hidden_states, tf.concat([tf.transpose(self.decoder), self.dense], axis=0))
hidden_states = hidden_states + self.bias
return hidden_states
class TFMobileBertMLMHead(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.predictions = TFMobileBertLMPredictionHead(config, name="predictions")
def call(self, sequence_output):
prediction_scores = self.predictions(sequence_output)
return prediction_scores
@keras_serializable
class TFMobileBertMainLayer(tf.keras.layers.Layer):
config_class = MobileBertConfig
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.num_hidden_layers = config.num_hidden_layers
self.output_attentions = config.output_attentions
self.output_hidden_states = config.output_hidden_states
self.embeddings = TFMobileBertEmbeddings(config, name="embeddings")
self.encoder = TFMobileBertEncoder(config, name="encoder")
self.pooler = TFMobileBertPooler(config, name="pooler")
def get_input_embeddings(self):
return self.embeddings
def _resize_token_embeddings(self, new_num_tokens):
raise NotImplementedError
def _prune_heads(self, heads_to_prune):
""" Prunes heads of the model.
heads_to_prune: dict of {layer_num: list of heads to prune in this layer}
See base class PreTrainedModel
"""
raise NotImplementedError
def call(
self,
inputs,
attention_mask=None,
token_type_ids=None,
position_ids=None,
head_mask=None,
inputs_embeds=None,
output_attentions=None,
output_hidden_states=None,
training=False,
):
if isinstance(inputs, (tuple, list)):
input_ids = inputs[0]
attention_mask = inputs[1] if len(inputs) > 1 else attention_mask
token_type_ids = inputs[2] if len(inputs) > 2 else token_type_ids
position_ids = inputs[3] if len(inputs) > 3 else position_ids
head_mask = inputs[4] if len(inputs) > 4 else head_mask
inputs_embeds = inputs[5] if len(inputs) > 5 else inputs_embeds
output_attentions = inputs[6] if len(inputs) > 6 else output_attentions
output_hidden_states = inputs[7] if len(inputs) > 7 else output_hidden_states
assert len(inputs) <= 8, "Too many inputs."
elif isinstance(inputs, (dict, BatchEncoding)):
input_ids = inputs.get("input_ids")
attention_mask = inputs.get("attention_mask", attention_mask)
token_type_ids = inputs.get("token_type_ids", token_type_ids)
position_ids = inputs.get("position_ids", position_ids)
head_mask = inputs.get("head_mask", head_mask)
inputs_embeds = inputs.get("inputs_embeds", inputs_embeds)
output_attentions = inputs.get("output_attentions", output_attentions)
output_hidden_states = inputs.get("output_hidden_states", output_hidden_states)
assert len(inputs) <= 8, "Too many inputs."
else:
input_ids = inputs
output_attentions = output_attentions if output_attentions is not None else self.output_attentions
output_hidden_states = output_hidden_states if output_hidden_states is not None else self.output_hidden_states
if input_ids is not None and inputs_embeds is not None:
raise ValueError("You cannot specify both input_ids and inputs_embeds at the same time")
elif input_ids is not None:
input_shape = shape_list(input_ids)
elif inputs_embeds is not None:
input_shape = shape_list(inputs_embeds)[:-1]
else:
raise ValueError("You have to specify either input_ids or inputs_embeds")
if attention_mask is None:
attention_mask = tf.fill(input_shape, 1)
if token_type_ids is None:
token_type_ids = tf.fill(input_shape, 0)
# We create a 3D attention mask from a 2D tensor mask.
# Sizes are [batch_size, 1, 1, to_seq_length]
# So we can broadcast to [batch_size, num_heads, from_seq_length, to_seq_length]
# this attention mask is more simple than the triangular masking of causal attention
# used in OpenAI GPT, we just need to prepare the broadcast dimension here.
extended_attention_mask = attention_mask[:, tf.newaxis, tf.newaxis, :]
# Since attention_mask is 1.0 for positions we want to attend and 0.0 for
# masked positions, this operation will create a tensor which is 0.0 for
# positions we want to attend and -10000.0 for masked positions.
# Since we are adding it to the raw scores before the softmax, this is
# effectively the same as removing these entirely.
extended_attention_mask = tf.cast(extended_attention_mask, tf.float32)
extended_attention_mask = (1.0 - extended_attention_mask) * -10000.0
# 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 seq_length x seq_length]
if head_mask is not None:
raise NotImplementedError
else:
head_mask = [None] * self.num_hidden_layers
# head_mask = tf.constant([0] * self.num_hidden_layers)
embedding_output = self.embeddings([input_ids, position_ids, token_type_ids, inputs_embeds], training=training)
encoder_outputs = self.encoder(
[embedding_output, extended_attention_mask, head_mask, output_attentions, output_hidden_states],
training=training,
)
sequence_output = encoder_outputs[0]
pooled_output = self.pooler(sequence_output)
outputs = (sequence_output, pooled_output,) + encoder_outputs[
1:
] # add hidden_states and attentions if they are here
return outputs # sequence_output, pooled_output, (hidden_states), (attentions)
class TFMobileBertPreTrainedModel(TFPreTrainedModel):
""" An abstract class to handle weights initialization and
a simple interface for downloading and loading pretrained models.
"""
config_class = MobileBertConfig
base_model_prefix = "mobilebert"
MOBILEBERT_START_DOCSTRING = r"""
This model is a `tf.keras.Model <https://www.tensorflow.org/api_docs/python/tf/keras/Model>`__ sub-class.
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 :obj:`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 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.MobileBertConfig`): 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.
"""
MOBILEBERT_INPUTS_DOCSTRING = r"""
Args:
input_ids (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`{0}`):
Indices of input sequence tokens in the vocabulary.
Indices can be obtained using :class:`transformers.MobileBertTokenizer`.
See :func:`transformers.PreTrainedTokenizer.encode` and
:func:`transformers.PreTrainedTokenizer.__call__` for details.
`What are input IDs? <../glossary.html#input-ids>`__
attention_mask (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`{0}`, `optional`, defaults to :obj:`None`):
Mask to avoid performing attention on padding token indices.
Mask values selected in ``[0, 1]``:
``1`` for tokens that are NOT MASKED, ``0`` for MASKED tokens.
`What are attention masks? <../glossary.html#attention-mask>`__
token_type_ids (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`{0}`, `optional`, defaults to :obj:`None`):
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:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`{0}`, `optional`, defaults to :obj:`None`):
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>`__
head_mask (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`(num_heads,)` or :obj:`(num_layers, num_heads)`, `optional`, defaults to :obj:`None`):
Mask to nullify selected heads of the self-attention modules.
Mask values selected in ``[0, 1]``:
:obj:`1` indicates the head is **not masked**, :obj:`0` indicates the head is **masked**.
inputs_embeds (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length, embedding_dim)`, `optional`, defaults to :obj:`None`):
Optionally, instead of passing :obj:`input_ids` you can to directly pass an embedded representation.
This is useful if you want more control over how to convert `input_ids` indices into associated vectors
than the model's internal embedding lookup matrix.
training (:obj:`boolean`, `optional`, defaults to :obj:`False`):
Whether to activate dropout modules (if set to :obj:`True`) during training or to de-activate them
(if set to :obj:`False`) for evaluation.
"""
[docs]@add_start_docstrings(
"The bare MobileBert Model transformer outputing raw hidden-states without any specific head on top.",
MOBILEBERT_START_DOCSTRING,
)
class TFMobileBertModel(TFMobileBertPreTrainedModel):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.mobilebert = TFMobileBertMainLayer(config, name="mobilebert")
[docs] @add_start_docstrings_to_callable(MOBILEBERT_INPUTS_DOCSTRING.format("(batch_size, sequence_length)"))
@add_code_sample_docstrings(tokenizer_class=_TOKENIZER_FOR_DOC, checkpoint="google/mobilebert-uncased")
def call(self, inputs, **kwargs):
r"""
Returns:
:obj:`tuple(tf.Tensor)` comprising various elements depending on the configuration (:class:`~transformers.MobileBertConfig`) and inputs:
last_hidden_state (:obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length, hidden_size)`):
Sequence of hidden-states at the output of the last layer of the model.
pooler_output (:obj:`tf.Tensor` of shape :obj:`(batch_size, hidden_size)`):
Last layer hidden-state of the first token of the sequence (classification token)
further processed by a Linear layer and a Tanh activation function. The Linear
layer weights are trained from the next sentence prediction (classification)
objective during the original Bert pretraining. This output is usually *not* a good summary
of the semantic content of the input, you're often better with averaging or pooling
the sequence of hidden-states for the whole input sequence.
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.
"""
outputs = self.mobilebert(inputs, **kwargs)
return outputs
[docs]@add_start_docstrings(
"""MobileBert Model with two heads on top as done during the pre-training:
a `masked language modeling` head and a `next sentence prediction (classification)` head. """,
MOBILEBERT_START_DOCSTRING,
)
class TFMobileBertForPreTraining(TFMobileBertPreTrainedModel):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.mobilebert = TFMobileBertMainLayer(config, name="mobilebert")
self.predictions = TFMobileBertMLMHead(config, name="predictions___cls")
self.seq_relationship = TFMobileBertOnlyNSPHead(2, name="seq_relationship___cls")
[docs] def get_output_embeddings(self):
return self.mobilebert.embeddings
[docs] @add_start_docstrings_to_callable(MOBILEBERT_INPUTS_DOCSTRING.format("(batch_size, sequence_length)"))
def call(self, inputs, **kwargs):
r"""
Return:
:obj:`tuple(tf.Tensor)` comprising various elements depending on the configuration (:class:`~transformers.MobileBertConfig`) and inputs:
prediction_scores (: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).
seq_relationship_scores (:obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length, 2)`):
Prediction scores of the next sequence prediction (classification) head (scores of True/False continuation 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.
Examples::
>>> import tensorflow as tf
>>> from transformers import MobileBertTokenizer, TFMobileBertForPreTraining
>>> tokenizer = MobileBertTokenizer.from_pretrained('google/mobilebert-uncased')
>>> model = TFMobileBertForPreTraining.from_pretrained('google/mobilebert-uncased')
>>> input_ids = tf.constant(tokenizer.encode("Hello, my dog is cute"))[None, :] # Batch size 1
>>> outputs = model(input_ids)
>>> prediction_scores, seq_relationship_scores = outputs[:2]
"""
outputs = self.mobilebert(inputs, **kwargs)
sequence_output, pooled_output = outputs[:2]
prediction_scores = self.predictions(sequence_output)
seq_relationship_score = self.seq_relationship(pooled_output)
outputs = (prediction_scores, seq_relationship_score,) + outputs[
2:
] # add hidden states and attention if they are here
return outputs # prediction_scores, seq_relationship_score, (hidden_states), (attentions)
class TFMobileBertOnlyNSPHead(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.seq_relationship = tf.keras.layers.Dense(2, name="seq_relationship")
def call(self, pooled_output):
seq_relationship_score = self.seq_relationship(pooled_output)
return seq_relationship_score
[docs]@add_start_docstrings(
"""MobileBert Model with a `next sentence prediction (classification)` head on top. """,
MOBILEBERT_START_DOCSTRING,
)
class TFMobileBertForNextSentencePrediction(TFMobileBertPreTrainedModel):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.mobilebert = TFMobileBertMainLayer(config, name="mobilebert")
self.cls = TFMobileBertOnlyNSPHead(config, name="seq_relationship___cls")
[docs] @add_start_docstrings_to_callable(MOBILEBERT_INPUTS_DOCSTRING.format("(batch_size, sequence_length)"))
def call(self, inputs, **kwargs):
r"""
Return:
:obj:`tuple(tf.Tensor)` comprising various elements depending on the configuration (:class:`~transformers.MobileBertConfig`) and inputs:
seq_relationship_scores (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length, 2)`)
Prediction scores of the next sequence prediction (classification) head (scores of True/False continuation 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.
Examples::
>>> import tensorflow as tf
>>> from transformers import MobileBertTokenizer, TFMobileBertForNextSentencePrediction
>>> tokenizer = MobileBertTokenizer.from_pretrained('google/mobilebert-uncased')
>>> model = TFMobileBertForNextSentencePrediction.from_pretrained('google/mobilebert-uncased')
>>> prompt = "In Italy, pizza served in formal settings, such as at a restaurant, is presented unsliced."
>>> next_sentence = "The sky is blue due to the shorter wavelength of blue light."
>>> encoding = tokenizer(prompt, next_sentence, return_tensors='tf')
>>> logits = model(encoding['input_ids'], token_type_ids=encoding['token_type_ids'])[0]
"""
outputs = self.mobilebert(inputs, **kwargs)
pooled_output = outputs[1]
seq_relationship_score = self.cls(pooled_output)
outputs = (seq_relationship_score,) + outputs[2:] # add hidden states and attention if they are here
return outputs # seq_relationship_score, (hidden_states), (attentions)
[docs]@add_start_docstrings(
"""MobileBert Model transformer with a sequence classification/regression head on top (a linear layer on top of
the pooled output) e.g. for GLUE tasks. """,
MOBILEBERT_START_DOCSTRING,
)
class TFMobileBertForSequenceClassification(TFMobileBertPreTrainedModel, TFSequenceClassificationLoss):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.num_labels = config.num_labels
self.mobilebert = TFMobileBertMainLayer(config, name="mobilebert")
self.dropout = tf.keras.layers.Dropout(config.hidden_dropout_prob)
self.classifier = tf.keras.layers.Dense(
config.num_labels, kernel_initializer=get_initializer(config.initializer_range), name="classifier"
)
[docs] @add_start_docstrings_to_callable(MOBILEBERT_INPUTS_DOCSTRING)
@add_code_sample_docstrings(tokenizer_class=_TOKENIZER_FOR_DOC, checkpoint="google/mobilebert-uncased")
def call(
self,
inputs=None,
attention_mask=None,
token_type_ids=None,
position_ids=None,
head_mask=None,
inputs_embeds=None,
output_attentions=None,
output_hidden_states=None,
labels=None,
training=False,
):
r"""
labels (:obj:`tf.Tensor` of shape :obj:`(batch_size,)`, `optional`, defaults to :obj:`None`):
Labels for computing the sequence classification/regression loss.
Indices should be in :obj:`[0, ..., config.num_labels - 1]`.
If :obj:`config.num_labels == 1` a regression loss is computed (Mean-Square loss),
If :obj:`config.num_labels > 1` a classification loss is computed (Cross-Entropy).
Return:
:obj:`tuple(tf.Tensor)` comprising various elements depending on the configuration (:class:`~transformers.MobileBertConfig`) and inputs:
logits (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`(batch_size, config.num_labels)`):
Classification (or regression if config.num_labels==1) scores (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.
"""
if isinstance(inputs, (tuple, list)):
labels = inputs[8] if len(inputs) > 8 else labels
if len(inputs) > 8:
inputs = inputs[:8]
elif isinstance(inputs, (dict, BatchEncoding)):
labels = inputs.pop("labels", labels)
outputs = self.mobilebert(
inputs,
attention_mask=attention_mask,
token_type_ids=token_type_ids,
position_ids=position_ids,
head_mask=head_mask,
inputs_embeds=inputs_embeds,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
training=training,
)
pooled_output = outputs[1]
pooled_output = self.dropout(pooled_output, training=training)
logits = self.classifier(pooled_output)
outputs = (logits,) + outputs[2:] # add hidden states and attention if they are here
if labels is not None:
loss = self.compute_loss(labels, logits)
outputs = (loss,) + outputs
return outputs # (loss), logits, (hidden_states), (attentions)
[docs]@add_start_docstrings(
"""MobileBert Model with a span classification head on top for extractive question-answering tasks like SQuAD (a linear layers on top of
the hidden-states output to compute `span start logits` and `span end logits`). """,
MOBILEBERT_START_DOCSTRING,
)
class TFMobileBertForQuestionAnswering(TFMobileBertPreTrainedModel, TFQuestionAnsweringLoss):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.num_labels = config.num_labels
self.mobilebert = TFMobileBertMainLayer(config, name="mobilebert")
self.qa_outputs = tf.keras.layers.Dense(
config.num_labels, kernel_initializer=get_initializer(config.initializer_range), name="qa_outputs"
)
[docs] @add_start_docstrings_to_callable(MOBILEBERT_INPUTS_DOCSTRING)
@add_code_sample_docstrings(tokenizer_class=_TOKENIZER_FOR_DOC, checkpoint="google/mobilebert-uncased")
def call(
self,
inputs=None,
attention_mask=None,
token_type_ids=None,
position_ids=None,
head_mask=None,
inputs_embeds=None,
output_attentions=None,
output_hidden_states=None,
start_positions=None,
end_positions=None,
training=False,
):
r"""
start_positions (:obj:`tf.Tensor` of shape :obj:`(batch_size,)`, `optional`, defaults to :obj:`None`):
Labels for position (index) of the start of the labelled span for computing the token classification loss.
Positions are clamped to the length of the sequence (`sequence_length`).
Position outside of the sequence are not taken into account for computing the loss.
end_positions (:obj:`tf.Tensor` of shape :obj:`(batch_size,)`, `optional`, defaults to :obj:`None`):
Labels for position (index) of the end of the labelled span for computing the token classification loss.
Positions are clamped to the length of the sequence (`sequence_length`).
Position outside of the sequence are not taken into account for computing the loss.
Return:
:obj:`tuple(tf.Tensor)` comprising various elements depending on the configuration (:class:`~transformers.MobileBertConfig`) and inputs:
start_scores (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length,)`):
Span-start scores (before SoftMax).
end_scores (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length,)`):
Span-end scores (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.
"""
if isinstance(inputs, (tuple, list)):
start_positions = inputs[8] if len(inputs) > 8 else start_positions
end_positions = inputs[9] if len(inputs) > 9 else end_positions
if len(inputs) > 8:
inputs = inputs[:8]
elif isinstance(inputs, (dict, BatchEncoding)):
start_positions = inputs.pop("start_positions", start_positions)
end_positions = inputs.pop("end_positions", start_positions)
outputs = self.mobilebert(
inputs,
attention_mask=attention_mask,
token_type_ids=token_type_ids,
position_ids=position_ids,
head_mask=head_mask,
inputs_embeds=inputs_embeds,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
training=training,
)
sequence_output = outputs[0]
logits = self.qa_outputs(sequence_output)
start_logits, end_logits = tf.split(logits, 2, axis=-1)
start_logits = tf.squeeze(start_logits, axis=-1)
end_logits = tf.squeeze(end_logits, axis=-1)
outputs = (start_logits, end_logits,) + outputs[2:]
if start_positions is not None and end_positions is not None:
labels = {"start_position": start_positions}
labels["end_position"] = end_positions
loss = self.compute_loss(labels, outputs[:2])
outputs = (loss,) + outputs
return outputs # (loss), start_logits, end_logits, (hidden_states), (attentions)
[docs]@add_start_docstrings(
"""MobileBert 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. """,
MOBILEBERT_START_DOCSTRING,
)
class TFMobileBertForTokenClassification(TFMobileBertPreTrainedModel, TFTokenClassificationLoss):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.num_labels = config.num_labels
self.mobilebert = TFMobileBertMainLayer(config, name="mobilebert")
self.dropout = tf.keras.layers.Dropout(config.hidden_dropout_prob)
self.classifier = tf.keras.layers.Dense(
config.num_labels, kernel_initializer=get_initializer(config.initializer_range), name="classifier"
)
[docs] @add_start_docstrings_to_callable(MOBILEBERT_INPUTS_DOCSTRING)
@add_code_sample_docstrings(tokenizer_class=_TOKENIZER_FOR_DOC, checkpoint="google/mobilebert-uncased")
def call(
self,
inputs=None,
attention_mask=None,
token_type_ids=None,
position_ids=None,
head_mask=None,
inputs_embeds=None,
output_attentions=None,
output_hidden_states=None,
labels=None,
training=False,
):
r"""
labels (:obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length)`, `optional`, defaults to :obj:`None`):
Labels for computing the token classification loss.
Indices should be in ``[0, ..., config.num_labels - 1]``.
Return:
:obj:`tuple(tf.Tensor)` comprising various elements depending on the configuration (:class:`~transformers.MobileBertConfig`) and inputs:
scores (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length, config.num_labels)`):
Classification scores (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.
"""
if isinstance(inputs, (tuple, list)):
labels = inputs[8] if len(inputs) > 8 else labels
if len(inputs) > 8:
inputs = inputs[:8]
elif isinstance(inputs, (dict, BatchEncoding)):
labels = inputs.pop("labels", labels)
outputs = self.mobilebert(
inputs,
attention_mask=attention_mask,
token_type_ids=token_type_ids,
position_ids=position_ids,
head_mask=head_mask,
inputs_embeds=inputs_embeds,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
training=training,
)
sequence_output = outputs[0]
sequence_output = self.dropout(sequence_output, training=training)
logits = self.classifier(sequence_output)
outputs = (logits,) + outputs[2:] # add hidden states and attention if they are here
if labels is not None:
loss = self.compute_loss(labels, logits)
outputs = (loss,) + outputs
return outputs # (loss), logits, (hidden_states), (attentions)