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modeling_tf_layoutlmv3.py
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modeling_tf_layoutlmv3.py
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# coding=utf-8
# Copyright 2022 Microsoft Research 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 LayoutLMv3 model."""
import collections
import math
from typing import Dict, List, Optional, Tuple, Union
import tensorflow as tf
from ...activations_tf import get_tf_activation
from ...modeling_tf_outputs import (
TFBaseModelOutput,
TFQuestionAnsweringModelOutput,
TFSequenceClassifierOutput,
TFTokenClassifierOutput,
)
from ...modeling_tf_utils import (
TFPreTrainedModel,
TFQuestionAnsweringLoss,
TFSequenceClassificationLoss,
TFTokenClassificationLoss,
get_initializer,
keras_serializable,
unpack_inputs,
)
from ...utils import add_start_docstrings, add_start_docstrings_to_model_forward, replace_return_docstrings
from .configuration_layoutlmv3 import LayoutLMv3Config
_CONFIG_FOR_DOC = "LayoutLMv3Config"
_DUMMY_INPUT_IDS = [
[7, 6, 1],
[1, 2, 0],
]
_DUMMY_BBOX = [
[[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]],
[[13, 14, 15, 16], [17, 18, 19, 20], [21, 22, 23, 24]],
]
TF_LAYOUTLMV3_PRETRAINED_MODEL_ARCHIVE_LIST = [
"microsoft/layoutlmv3-base",
"microsoft/layoutlmv3-large",
# See all LayoutLMv3 models at https://huggingface.co/models?filter=layoutlmv3
]
LARGE_NEGATIVE = -1e8
class TFLayoutLMv3PatchEmbeddings(tf.keras.layers.Layer):
"""LayoutLMv3 image (patch) embeddings."""
def __init__(self, config: LayoutLMv3Config, **kwargs):
super().__init__(**kwargs)
patch_sizes = (
config.patch_size
if isinstance(config.patch_size, collections.abc.Iterable)
else (config.patch_size, config.patch_size)
)
self.proj = tf.keras.layers.Conv2D(
filters=config.hidden_size,
kernel_size=patch_sizes,
strides=patch_sizes,
padding="valid",
data_format="channels_last",
use_bias=True,
kernel_initializer=get_initializer(config.initializer_range),
name="proj",
)
self.hidden_size = config.hidden_size
self.num_patches = (config.input_size**2) // (patch_sizes[0] * patch_sizes[1])
def call(self, pixel_values: tf.Tensor) -> tf.Tensor:
# When running on CPU, `tf.keras.layers.Conv2D` doesn't support `NCHW` format.
# So change the input format from `NCHW` to `NHWC`.
pixel_values = tf.transpose(pixel_values, perm=[0, 2, 3, 1])
embeddings = self.proj(pixel_values)
embeddings = tf.reshape(embeddings, (-1, self.num_patches, self.hidden_size))
return embeddings
class TFLayoutLMv3TextEmbeddings(tf.keras.layers.Layer):
"""
LayoutLMv3 text embeddings. Same as `RobertaEmbeddings` but with added spatial (layout) embeddings.
"""
def __init__(self, config: LayoutLMv3Config, **kwargs):
super().__init__(**kwargs)
self.word_embeddings = tf.keras.layers.Embedding(
config.vocab_size,
config.hidden_size,
embeddings_initializer=get_initializer(config.initializer_range),
name="word_embeddings",
)
self.token_type_embeddings = tf.keras.layers.Embedding(
config.type_vocab_size,
config.hidden_size,
embeddings_initializer=get_initializer(config.initializer_range),
name="token_type_embeddings",
)
self.LayerNorm = tf.keras.layers.LayerNormalization(epsilon=config.layer_norm_eps, name="LayerNorm")
self.dropout = tf.keras.layers.Dropout(config.hidden_dropout_prob)
self.padding_token_index = config.pad_token_id
self.position_embeddings = tf.keras.layers.Embedding(
config.max_position_embeddings,
config.hidden_size,
embeddings_initializer=get_initializer(config.initializer_range),
name="position_embeddings",
)
self.x_position_embeddings = tf.keras.layers.Embedding(
config.max_2d_position_embeddings,
config.coordinate_size,
embeddings_initializer=get_initializer(config.initializer_range),
name="x_position_embeddings",
)
self.y_position_embeddings = tf.keras.layers.Embedding(
config.max_2d_position_embeddings,
config.coordinate_size,
embeddings_initializer=get_initializer(config.initializer_range),
name="y_position_embeddings",
)
self.h_position_embeddings = tf.keras.layers.Embedding(
config.max_2d_position_embeddings,
config.shape_size,
embeddings_initializer=get_initializer(config.initializer_range),
name="h_position_embeddings",
)
self.w_position_embeddings = tf.keras.layers.Embedding(
config.max_2d_position_embeddings,
config.shape_size,
embeddings_initializer=get_initializer(config.initializer_range),
name="w_position_embeddings",
)
self.max_2d_positions = config.max_2d_position_embeddings
def calculate_spatial_position_embeddings(self, bbox: tf.Tensor) -> tf.Tensor:
try:
left_position_ids = bbox[:, :, 0]
upper_position_ids = bbox[:, :, 1]
right_position_ids = bbox[:, :, 2]
lower_position_ids = bbox[:, :, 3]
except IndexError as exception:
raise IndexError("Bounding box is not of shape (batch_size, seq_length, 4).") from exception
try:
left_position_embeddings = self.x_position_embeddings(left_position_ids)
upper_position_embeddings = self.y_position_embeddings(upper_position_ids)
right_position_embeddings = self.x_position_embeddings(right_position_ids)
lower_position_embeddings = self.y_position_embeddings(lower_position_ids)
except IndexError as exception:
raise IndexError(
f"The `bbox` coordinate values should be within 0-{self.max_2d_positions} range."
) from exception
max_position_id = self.max_2d_positions - 1
h_position_embeddings = self.h_position_embeddings(
tf.clip_by_value(bbox[:, :, 3] - bbox[:, :, 1], 0, max_position_id)
)
w_position_embeddings = self.w_position_embeddings(
tf.clip_by_value(bbox[:, :, 2] - bbox[:, :, 0], 0, max_position_id)
)
# LayoutLMv1 sums the spatial embeddings, but LayoutLMv3 concatenates them.
spatial_position_embeddings = tf.concat(
[
left_position_embeddings,
upper_position_embeddings,
right_position_embeddings,
lower_position_embeddings,
h_position_embeddings,
w_position_embeddings,
],
axis=-1,
)
return spatial_position_embeddings
def create_position_ids_from_inputs_embeds(self, inputs_embds: tf.Tensor) -> tf.Tensor:
"""
We are provided embeddings directly. We cannot infer which are padded, so just generate sequential position
ids.
"""
input_shape = tf.shape(inputs_embds)
sequence_length = input_shape[1]
start_index = self.padding_token_index + 1
end_index = self.padding_token_index + sequence_length + 1
position_ids = tf.range(start_index, end_index, dtype=tf.int32)
batch_size = input_shape[0]
position_ids = tf.reshape(position_ids, (1, sequence_length))
position_ids = tf.tile(position_ids, (batch_size, 1))
return position_ids
def create_position_ids_from_input_ids(self, input_ids: tf.Tensor) -> tf.Tensor:
"""
Replace non-padding symbols with their position numbers. Position numbers begin at padding_token_index + 1.
"""
mask = tf.cast(tf.not_equal(input_ids, self.padding_token_index), input_ids.dtype)
position_ids = tf.cumsum(mask, axis=1) * mask
position_ids = position_ids + self.padding_token_index
return position_ids
def create_position_ids(self, input_ids: tf.Tensor, inputs_embeds: tf.Tensor) -> tf.Tensor:
if input_ids is None:
return self.create_position_ids_from_inputs_embeds(inputs_embeds)
else:
return self.create_position_ids_from_input_ids(input_ids)
def call(
self,
input_ids: Optional[tf.Tensor] = None,
bbox: tf.Tensor = None,
token_type_ids: Optional[tf.Tensor] = None,
position_ids: Optional[tf.Tensor] = None,
inputs_embeds: Optional[tf.Tensor] = None,
training: bool = False,
) -> tf.Tensor:
if position_ids is None:
position_ids = self.create_position_ids(input_ids, inputs_embeds)
if input_ids is not None:
input_shape = tf.shape(input_ids)
else:
input_shape = tf.shape(inputs_embeds)[:-1]
if token_type_ids is None:
token_type_ids = tf.zeros(input_shape, dtype=position_ids.dtype)
if inputs_embeds is None:
# Note: tf.gather, on which the embedding layer is based, won't check positive out of bound
# indices on GPU, returning zeros instead. This is a dangerous silent behavior.
tf.debugging.assert_less(
input_ids,
tf.cast(self.word_embeddings.input_dim, dtype=input_ids.dtype),
message=(
"input_ids must be smaller than the embedding layer's input dimension (got"
f" {tf.math.reduce_max(input_ids)} >= {self.word_embeddings.input_dim})"
),
)
inputs_embeds = self.word_embeddings(input_ids)
token_type_embeddings = self.token_type_embeddings(token_type_ids)
embeddings = inputs_embeds + token_type_embeddings
position_embeddings = self.position_embeddings(position_ids)
embeddings += position_embeddings
spatial_position_embeddings = self.calculate_spatial_position_embeddings(bbox)
embeddings += spatial_position_embeddings
embeddings = self.LayerNorm(embeddings)
embeddings = self.dropout(embeddings, training=training)
return embeddings
class TFLayoutLMv3SelfAttention(tf.keras.layers.Layer):
def __init__(self, config: LayoutLMv3Config, **kwargs):
super().__init__(**kwargs)
if config.hidden_size % config.num_attention_heads != 0:
raise ValueError(
f"The hidden size ({config.hidden_size}) is not a multiple of the number of attention "
f"heads ({config.num_attention_heads})"
)
self.num_attention_heads = config.num_attention_heads
self.attention_head_size = int(config.hidden_size / config.num_attention_heads)
self.all_head_size = self.num_attention_heads * self.attention_head_size
self.attention_score_normaliser = math.sqrt(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)
self.has_relative_attention_bias = config.has_relative_attention_bias
self.has_spatial_attention_bias = config.has_spatial_attention_bias
def transpose_for_scores(self, x: tf.Tensor):
shape = tf.shape(x)
new_shape = (
shape[0], # batch_size
shape[1], # seq_length
self.num_attention_heads,
self.attention_head_size,
)
x = tf.reshape(x, new_shape)
return tf.transpose(x, perm=[0, 2, 1, 3]) # batch_size, num_heads, seq_length, attention_head_size
def cogview_attention(self, attention_scores: tf.Tensor, alpha: Union[float, int] = 32):
"""
https://arxiv.org/abs/2105.13290 Section 2.4 Stabilization of training: Precision Bottleneck Relaxation
(PB-Relax). A replacement of the original tf.keras.layers.Softmax(axis=-1)(attention_scores). Seems the new
attention_probs will result in a slower speed and a little bias. Can use
tf.debugging.assert_near(standard_attention_probs, cogview_attention_probs, atol=1e-08) for comparison. The
smaller atol (e.g., 1e-08), the better.
"""
scaled_attention_scores = attention_scores / alpha
max_value = tf.expand_dims(tf.reduce_max(scaled_attention_scores, axis=-1), axis=-1)
new_attention_scores = (scaled_attention_scores - max_value) * alpha
return tf.math.softmax(new_attention_scores, axis=-1)
def call(
self,
hidden_states: tf.Tensor,
attention_mask: Optional[tf.Tensor],
head_mask: Optional[tf.Tensor],
output_attentions: bool,
rel_pos: Optional[tf.Tensor] = None,
rel_2d_pos: Optional[tf.Tensor] = None,
training: bool = False,
) -> Union[Tuple[tf.Tensor], Tuple[tf.Tensor, tf.Tensor]]:
key_layer = self.transpose_for_scores(self.key(hidden_states))
value_layer = self.transpose_for_scores(self.value(hidden_states))
query_layer = self.transpose_for_scores(self.query(hidden_states))
# Take the dot product between "query" and "key" to get the raw attention scores.
normalised_query_layer = query_layer / self.attention_score_normaliser
transposed_key_layer = tf.transpose(
key_layer, perm=[0, 1, 3, 2]
) # batch_size, num_heads, attention_head_size, seq_length
attention_scores = tf.matmul(normalised_query_layer, transposed_key_layer)
if self.has_relative_attention_bias and self.has_spatial_attention_bias:
attention_scores += (rel_pos + rel_2d_pos) / self.attention_score_normaliser
elif self.has_relative_attention_bias:
attention_scores += rel_pos / self.attention_score_normaliser
if attention_mask is not None:
# Apply the attention mask (is precomputed for all layers in TFLayoutLMv3Model call() function)
attention_scores += attention_mask
# Normalize the attention scores to probabilities.
# Use the trick of CogView paper to stabilize training.
attention_probs = self.cogview_attention(attention_scores)
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]
) # batch_size, seq_length, num_heads, attention_head_size
shape = tf.shape(context_layer)
context_layer = tf.reshape(
context_layer, (shape[0], shape[1], self.all_head_size)
) # batch_size, seq_length, num_heads * attention_head_size
outputs = (context_layer, attention_probs) if output_attentions else (context_layer,)
return outputs
# Copied from models.roberta.modeling_tf_roberta.TFRobertaSelfOutput
class TFLayoutLMv3SelfOutput(tf.keras.layers.Layer):
def __init__(self, config: LayoutLMv3Config, **kwargs):
super().__init__(**kwargs)
self.dense = tf.keras.layers.Dense(
units=config.hidden_size, kernel_initializer=get_initializer(config.initializer_range), name="dense"
)
self.LayerNorm = tf.keras.layers.LayerNormalization(epsilon=config.layer_norm_eps, name="LayerNorm")
self.dropout = tf.keras.layers.Dropout(rate=config.hidden_dropout_prob)
def call(self, hidden_states: tf.Tensor, input_tensor: tf.Tensor, training: bool = False) -> tf.Tensor:
hidden_states = self.dense(inputs=hidden_states)
hidden_states = self.dropout(inputs=hidden_states, training=training)
hidden_states = self.LayerNorm(inputs=hidden_states + input_tensor)
return hidden_states
class TFLayoutLMv3Attention(tf.keras.layers.Layer):
def __init__(self, config: LayoutLMv3Config, **kwargs):
super().__init__(**kwargs)
self.self_attention = TFLayoutLMv3SelfAttention(config, name="self")
self.self_output = TFLayoutLMv3SelfOutput(config, name="output")
def call(
self,
hidden_states: tf.Tensor,
attention_mask: Optional[tf.Tensor],
head_mask: Optional[tf.Tensor],
output_attentions: bool,
rel_pos: Optional[tf.Tensor] = None,
rel_2d_pos: Optional[tf.Tensor] = None,
training: bool = False,
) -> Union[Tuple[tf.Tensor], Tuple[tf.Tensor, tf.Tensor]]:
self_outputs = self.self_attention(
hidden_states,
attention_mask,
head_mask,
output_attentions,
rel_pos,
rel_2d_pos,
training=training,
)
attention_output = self.self_output(self_outputs[0], hidden_states, training=training)
outputs = (attention_output,) + self_outputs[1:] # add attentions if we output them
return outputs
# Copied from models.roberta.modeling_tf_bert.TFRobertaIntermediate
class TFLayoutLMv3Intermediate(tf.keras.layers.Layer):
def __init__(self, config: LayoutLMv3Config, **kwargs):
super().__init__(**kwargs)
self.dense = tf.keras.layers.Dense(
units=config.intermediate_size, kernel_initializer=get_initializer(config.initializer_range), name="dense"
)
if isinstance(config.hidden_act, str):
self.intermediate_act_fn = get_tf_activation(config.hidden_act)
else:
self.intermediate_act_fn = config.hidden_act
def call(self, hidden_states: tf.Tensor) -> tf.Tensor:
hidden_states = self.dense(inputs=hidden_states)
hidden_states = self.intermediate_act_fn(hidden_states)
return hidden_states
# Copied from models.roberta.modeling_tf_bert.TFRobertaOutput
class TFLayoutLMv3Output(tf.keras.layers.Layer):
def __init__(self, config: LayoutLMv3Config, **kwargs):
super().__init__(**kwargs)
self.dense = tf.keras.layers.Dense(
units=config.hidden_size, kernel_initializer=get_initializer(config.initializer_range), name="dense"
)
self.LayerNorm = tf.keras.layers.LayerNormalization(epsilon=config.layer_norm_eps, name="LayerNorm")
self.dropout = tf.keras.layers.Dropout(rate=config.hidden_dropout_prob)
def call(self, hidden_states: tf.Tensor, input_tensor: tf.Tensor, training: bool = False) -> tf.Tensor:
hidden_states = self.dense(inputs=hidden_states)
hidden_states = self.dropout(inputs=hidden_states, training=training)
hidden_states = self.LayerNorm(inputs=hidden_states + input_tensor)
return hidden_states
class TFLayoutLMv3Layer(tf.keras.layers.Layer):
def __init__(self, config: LayoutLMv3Config, **kwargs):
super().__init__(**kwargs)
self.attention = TFLayoutLMv3Attention(config, name="attention")
self.intermediate = TFLayoutLMv3Intermediate(config, name="intermediate")
self.bert_output = TFLayoutLMv3Output(config, name="output")
def call(
self,
hidden_states: tf.Tensor,
attention_mask: Optional[tf.Tensor],
head_mask: Optional[tf.Tensor],
output_attentions: bool,
rel_pos: Optional[tf.Tensor] = None,
rel_2d_pos: Optional[tf.Tensor] = None,
training: bool = False,
) -> Union[Tuple[tf.Tensor], Tuple[tf.Tensor, tf.Tensor]]:
self_attention_outputs = self.attention(
hidden_states,
attention_mask,
head_mask,
output_attentions=output_attentions,
rel_pos=rel_pos,
rel_2d_pos=rel_2d_pos,
training=training,
)
attention_output = self_attention_outputs[0]
outputs = self_attention_outputs[1:] # add self attentions if we output attention weights
intermediate_output = self.intermediate(attention_output)
layer_output = self.bert_output(intermediate_output, attention_output, training=training)
outputs = (layer_output,) + outputs
return outputs
class TFLayoutLMv3Encoder(tf.keras.layers.Layer):
def __init__(self, config: LayoutLMv3Config, **kwargs):
super().__init__(**kwargs)
self.config = config
self.layer = [TFLayoutLMv3Layer(config, name=f"layer.{i}") for i in range(config.num_hidden_layers)]
self.has_relative_attention_bias = config.has_relative_attention_bias
self.has_spatial_attention_bias = config.has_spatial_attention_bias
if self.has_relative_attention_bias:
self.rel_pos_bins = config.rel_pos_bins
self.max_rel_pos = config.max_rel_pos
self.rel_pos_bias = tf.keras.layers.Dense(
units=config.num_attention_heads,
kernel_initializer=get_initializer(config.initializer_range),
use_bias=False,
name="rel_pos_bias",
)
if self.has_spatial_attention_bias:
self.max_rel_2d_pos = config.max_rel_2d_pos
self.rel_2d_pos_bins = config.rel_2d_pos_bins
self.rel_pos_x_bias = tf.keras.layers.Dense(
units=config.num_attention_heads,
kernel_initializer=get_initializer(config.initializer_range),
use_bias=False,
name="rel_pos_x_bias",
)
self.rel_pos_y_bias = tf.keras.layers.Dense(
units=config.num_attention_heads,
kernel_initializer=get_initializer(config.initializer_range),
use_bias=False,
name="rel_pos_y_bias",
)
def relative_position_bucket(self, relative_positions: tf.Tensor, num_buckets: int, max_distance: int):
# the negative relative positions are assigned to the interval [0, num_buckets / 2]
# we deal with this by assigning absolute relative positions to the interval [0, num_buckets / 2]
# and then offsetting the positive relative positions by num_buckets / 2 at the end
num_buckets = num_buckets // 2
buckets = tf.abs(relative_positions)
# half of the buckets are for exact increments in positions
max_exact_buckets = num_buckets // 2
is_small = buckets < max_exact_buckets
# the other half of the buckets are for logarithmically bigger bins in positions up to max_distance
buckets_log_ratio = tf.math.log(tf.cast(buckets, tf.float32) / max_exact_buckets)
distance_log_ratio = math.log(max_distance / max_exact_buckets)
buckets_big_offset = (
buckets_log_ratio / distance_log_ratio * (num_buckets - max_exact_buckets)
) # scale is [0, num_buckets - max_exact_buckets]
buckets_big = max_exact_buckets + buckets_big_offset # scale is [max_exact_buckets, num_buckets]
buckets_big = tf.cast(buckets_big, buckets.dtype)
buckets_big = tf.minimum(buckets_big, num_buckets - 1)
return (tf.cast(relative_positions > 0, buckets.dtype) * num_buckets) + tf.where(
is_small, buckets, buckets_big
)
def _cal_pos_emb(
self,
dense_layer: tf.keras.layers.Dense,
position_ids: tf.Tensor,
num_buckets: int,
max_distance: int,
):
rel_pos_matrix = tf.expand_dims(position_ids, axis=-2) - tf.expand_dims(position_ids, axis=-1)
rel_pos = self.relative_position_bucket(rel_pos_matrix, num_buckets, max_distance)
rel_pos_one_hot = tf.one_hot(rel_pos, depth=num_buckets, dtype=self.compute_dtype)
embedding = dense_layer(rel_pos_one_hot)
# batch_size, seq_length, seq_length, num_heads --> batch_size, num_heads, seq_length, seq_length
embedding = tf.transpose(embedding, [0, 3, 1, 2])
embedding = tf.cast(embedding, dtype=self.compute_dtype)
return embedding
def _cal_1d_pos_emb(self, position_ids: tf.Tensor):
return self._cal_pos_emb(self.rel_pos_bias, position_ids, self.rel_pos_bins, self.max_rel_pos)
def _cal_2d_pos_emb(self, bbox: tf.Tensor):
position_coord_x = bbox[:, :, 0] # left
position_coord_y = bbox[:, :, 3] # bottom
rel_pos_x = self._cal_pos_emb(
self.rel_pos_x_bias,
position_coord_x,
self.rel_2d_pos_bins,
self.max_rel_2d_pos,
)
rel_pos_y = self._cal_pos_emb(
self.rel_pos_y_bias,
position_coord_y,
self.rel_2d_pos_bins,
self.max_rel_2d_pos,
)
rel_2d_pos = rel_pos_x + rel_pos_y
return rel_2d_pos
def call(
self,
hidden_states: tf.Tensor,
bbox: Optional[tf.Tensor] = None,
attention_mask: Optional[tf.Tensor] = None,
head_mask: Optional[tf.Tensor] = None,
output_attentions: bool = False,
output_hidden_states: bool = False,
return_dict: bool = True,
position_ids: Optional[tf.Tensor] = None,
training: bool = False,
) -> Union[
TFBaseModelOutput,
Tuple[tf.Tensor],
Tuple[tf.Tensor, tf.Tensor],
Tuple[tf.Tensor, tf.Tensor, tf.Tensor],
]:
all_hidden_states = () if output_hidden_states else None
all_self_attentions = () if output_attentions else None
rel_pos = self._cal_1d_pos_emb(position_ids) if self.has_relative_attention_bias else None
rel_2d_pos = self._cal_2d_pos_emb(bbox) if self.has_spatial_attention_bias else None
for i, layer_module in enumerate(self.layer):
if output_hidden_states:
all_hidden_states = all_hidden_states + (hidden_states,)
layer_head_mask = head_mask[i] if head_mask is not None else None
layer_outputs = layer_module(
hidden_states,
attention_mask,
layer_head_mask,
output_attentions,
rel_pos=rel_pos,
rel_2d_pos=rel_2d_pos,
training=training,
)
hidden_states = layer_outputs[0]
if output_attentions:
all_self_attentions = all_self_attentions + (layer_outputs[1],)
if output_hidden_states:
all_hidden_states = all_hidden_states + (hidden_states,)
if return_dict:
return TFBaseModelOutput(
last_hidden_state=hidden_states,
hidden_states=all_hidden_states,
attentions=all_self_attentions,
)
else:
return tuple(
value for value in [hidden_states, all_hidden_states, all_self_attentions] if value is not None
)
@keras_serializable
class TFLayoutLMv3MainLayer(tf.keras.layers.Layer):
config_class = LayoutLMv3Config
def __init__(self, config: LayoutLMv3Config, **kwargs):
super().__init__(**kwargs)
self.config = config
if config.text_embed:
self.embeddings = TFLayoutLMv3TextEmbeddings(config, name="embeddings")
if config.visual_embed:
self.patch_embed = TFLayoutLMv3PatchEmbeddings(config, name="patch_embed")
self.LayerNorm = tf.keras.layers.LayerNormalization(epsilon=config.layer_norm_eps, name="LayerNorm")
self.dropout = tf.keras.layers.Dropout(config.hidden_dropout_prob, name="dropout")
if config.has_relative_attention_bias or config.has_spatial_attention_bias:
image_size = config.input_size // config.patch_size
self.init_visual_bbox(image_size=(image_size, image_size))
self.norm = tf.keras.layers.LayerNormalization(epsilon=1e-6, name="norm")
self.encoder = TFLayoutLMv3Encoder(config, name="encoder")
def build(self, input_shape: tf.TensorShape):
if self.config.visual_embed:
image_size = self.config.input_size // self.config.patch_size
self.cls_token = self.add_weight(
shape=(1, 1, self.config.hidden_size),
initializer="zeros",
trainable=True,
dtype=tf.float32,
name="cls_token",
)
self.pos_embed = self.add_weight(
shape=(1, image_size * image_size + 1, self.config.hidden_size),
initializer="zeros",
trainable=True,
dtype=tf.float32,
name="pos_embed",
)
super().build(input_shape)
def get_input_embeddings(self) -> tf.keras.layers.Layer:
return self.embeddings.word_embeddings
def set_input_embeddings(self, value: tf.Variable):
self.embeddings.word_embeddings.weight = value
# Copied from transformers.models.bert.modeling_tf_bert.TFBertMainLayer._prune_heads
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 init_visual_bbox(self, image_size: Tuple[int, int], max_len: int = 1000):
# We should not hardcode max_len to 1000, but it is done by the reference implementation,
# so we keep it for compatibility with the pretrained weights. The more correct approach
# would have been to pass on max_len=config.max_2d_position_embeddings - 1.
height, width = image_size
visual_bbox_x = tf.range(0, max_len * (width + 1), max_len) // width
visual_bbox_x = tf.expand_dims(visual_bbox_x, axis=0)
visual_bbox_x = tf.tile(visual_bbox_x, [width, 1]) # (width, width + 1)
visual_bbox_y = tf.range(0, max_len * (height + 1), max_len) // height
visual_bbox_y = tf.expand_dims(visual_bbox_y, axis=1)
visual_bbox_y = tf.tile(visual_bbox_y, [1, height]) # (height + 1, height)
visual_bbox = tf.stack(
[visual_bbox_x[:, :-1], visual_bbox_y[:-1], visual_bbox_x[:, 1:], visual_bbox_y[1:]],
axis=-1,
)
visual_bbox = tf.reshape(visual_bbox, [-1, 4])
cls_token_box = tf.constant([[1, 1, max_len - 1, max_len - 1]], dtype=tf.int32)
self.visual_bbox = tf.concat([cls_token_box, visual_bbox], axis=0)
def calculate_visual_bbox(self, batch_size: int, dtype: tf.DType):
visual_bbox = tf.expand_dims(self.visual_bbox, axis=0)
visual_bbox = tf.tile(visual_bbox, [batch_size, 1, 1])
visual_bbox = tf.cast(visual_bbox, dtype=dtype)
return visual_bbox
def embed_image(self, pixel_values: tf.Tensor) -> tf.Tensor:
embeddings = self.patch_embed(pixel_values)
# add [CLS] token
batch_size = tf.shape(embeddings)[0]
cls_tokens = tf.tile(self.cls_token, [batch_size, 1, 1])
embeddings = tf.concat([cls_tokens, embeddings], axis=1)
# add position embeddings
if getattr(self, "pos_embed", None) is not None:
embeddings += self.pos_embed
embeddings = self.norm(embeddings)
return embeddings
def get_extended_attention_mask(self, attention_mask: tf.Tensor) -> tf.Tensor:
# Adapted from transformers.modelling_utils.ModuleUtilsMixin.get_extended_attention_mask
n_dims = len(attention_mask.shape)
# We can provide a self-attention mask of dimensions [batch_size, from_seq_length, to_seq_length]
# ourselves in which case we just need to make it broadcastable to all heads.
if n_dims == 3:
extended_attention_mask = tf.expand_dims(attention_mask, axis=1)
elif n_dims == 2:
# Provided a padding mask of dimensions [batch_size, seq_length].
# Make the mask broadcastable to [batch_size, num_heads, seq_length, seq_length].
extended_attention_mask = tf.expand_dims(attention_mask, axis=1) # (batch_size, 1, seq_length)
extended_attention_mask = tf.expand_dims(extended_attention_mask, axis=1) # (batch_size, 1, 1, seq_length)
else:
raise ValueError(f"Wrong shape for attention_mask (shape {attention_mask.shape}).")
# 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, self.compute_dtype)
extended_attention_mask = (1.0 - extended_attention_mask) * LARGE_NEGATIVE
return extended_attention_mask
def get_head_mask(self, head_mask: Optional[tf.Tensor]) -> Union[tf.Tensor, List[Optional[tf.Tensor]]]:
if head_mask is None:
return [None] * self.config.num_hidden_layers
n_dims = tf.rank(head_mask)
if n_dims == 1:
# Gets a tensor with masks for each head (H).
head_mask = tf.expand_dims(head_mask, axis=0) # 1, num_heads
head_mask = tf.expand_dims(head_mask, axis=0) # 1, 1, num_heads
head_mask = tf.expand_dims(head_mask, axis=-1) # 1, 1, num_heads, 1
head_mask = tf.expand_dims(head_mask, axis=-1) # 1, 1, num_heads, 1, 1
head_mask = tf.tile(
head_mask, [self.config.num_hidden_layers, 1, 1, 1, 1]
) # seq_length, 1, num_heads, 1, 1
elif n_dims == 2:
# Gets a tensor with masks for each layer (L) and head (H).
head_mask = tf.expand_dims(head_mask, axis=1) # seq_length, 1, num_heads
head_mask = tf.expand_dims(head_mask, axis=-1) # seq_length, 1, num_heads, 1
head_mask = tf.expand_dims(head_mask, axis=-1) # seq_length, 1, num_heads, 1, 1
elif n_dims != 5:
raise ValueError(f"Wrong shape for head_mask (shape {head_mask.shape}).")
assert tf.rank(head_mask) == 5, f"Got head_mask rank of {tf.rank(head_mask)}, but require 5."
head_mask = tf.cast(head_mask, self.compute_dtype)
return head_mask
@unpack_inputs
def call(
self,
input_ids: Optional[tf.Tensor] = None,
bbox: Optional[tf.Tensor] = None,
attention_mask: Optional[tf.Tensor] = None,
token_type_ids: Optional[tf.Tensor] = None,
position_ids: Optional[tf.Tensor] = None,
head_mask: Optional[tf.Tensor] = None,
inputs_embeds: Optional[tf.Tensor] = None,
pixel_values: Optional[tf.Tensor] = None,
output_attentions: Optional[bool] = None,
output_hidden_states: Optional[bool] = None,
return_dict: Optional[bool] = None,
training: bool = False,
) -> Union[
TFBaseModelOutput,
Tuple[tf.Tensor],
Tuple[tf.Tensor, tf.Tensor],
Tuple[tf.Tensor, tf.Tensor, tf.Tensor],
]:
# This method can be called with a variety of modalities:
# 1. text + layout
# 2. text + layout + image
# 3. image
# The complexity of this method is mostly just due to handling of these different modalities.
output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
output_hidden_states = (
output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
)
return_dict = return_dict if return_dict is not None else self.config.return_dict
if input_ids is not None:
input_shape = tf.shape(input_ids)
batch_size = input_shape[0]
seq_length = input_shape[1]
elif inputs_embeds is not None:
input_shape = tf.shape(inputs_embeds)
batch_size = input_shape[0]
seq_length = input_shape[1]
elif pixel_values is not None:
batch_size = tf.shape(pixel_values)[0]
else:
raise ValueError("You have to specify either input_ids or inputs_embeds or pixel_values")
# Determine which integer dtype to use.
if input_ids is not None:
int_dtype = input_ids.dtype
elif bbox is not None:
int_dtype = bbox.dtype
elif attention_mask is not None:
int_dtype = attention_mask.dtype
elif token_type_ids is not None:
int_dtype = token_type_ids.dtype
else:
int_dtype = tf.int32
if input_ids is not None or inputs_embeds is not None:
if attention_mask is None:
attention_mask = tf.ones((batch_size, seq_length), dtype=int_dtype)
if token_type_ids is None:
token_type_ids = tf.zeros((batch_size, seq_length), dtype=int_dtype)
if bbox is None:
bbox = tf.zeros((batch_size, seq_length, 4), dtype=int_dtype)
embedding_output = self.embeddings(
input_ids=input_ids,
bbox=bbox,
position_ids=position_ids,
token_type_ids=token_type_ids,
inputs_embeds=inputs_embeds,
training=training,
)
final_bbox = None
final_position_ids = None
if pixel_values is not None:
# embed image
visual_embeddings = self.embed_image(pixel_values)
# calculate attention mask
visual_attention_mask = tf.ones((batch_size, tf.shape(visual_embeddings)[1]), dtype=int_dtype)
if attention_mask is None:
attention_mask = visual_attention_mask
else:
attention_mask = tf.concat([attention_mask, visual_attention_mask], axis=1)
# calculate bounding boxes
if self.config.has_spatial_attention_bias:
visual_bbox = self.calculate_visual_bbox(batch_size, int_dtype)
if bbox is None:
final_bbox = visual_bbox
else:
final_bbox = tf.concat([bbox, visual_bbox], axis=1)
# calculate position IDs
if self.config.has_relative_attention_bias or self.config.has_spatial_attention_bias:
visual_position_ids = tf.range(0, tf.shape(visual_embeddings)[1], dtype=int_dtype)
visual_position_ids = tf.expand_dims(visual_position_ids, axis=0)
visual_position_ids = tf.tile(visual_position_ids, [batch_size, 1])
if input_ids is not None or inputs_embeds is not None:
position_ids = tf.expand_dims(tf.range(0, seq_length, dtype=int_dtype), axis=0)
position_ids = tf.tile(position_ids, [batch_size, 1])
final_position_ids = tf.concat([position_ids, visual_position_ids], axis=1)
else:
final_position_ids = visual_position_ids
# calculate embeddings
if input_ids is None and inputs_embeds is None:
embedding_output = visual_embeddings
else:
embedding_output = tf.concat([embedding_output, visual_embeddings], axis=1)
embedding_output = self.LayerNorm(embedding_output)
embedding_output = self.dropout(embedding_output, training=training)
elif self.config.has_relative_attention_bias or self.config.has_spatial_attention_bias:
if self.config.has_relative_attention_bias:
position_ids = tf.expand_dims(tf.range(0, seq_length, dtype=int_dtype), axis=0)
position_ids = tf.tile(position_ids, [batch_size, 1])
final_position_ids = position_ids
if self.config.has_spatial_attention_bias:
final_bbox = bbox
extended_attention_mask = self.get_extended_attention_mask(attention_mask)
# Prepare head mask if needed
# 1.0 in head_mask indicate we keep the head
# attention_probs has shape batch_size x num_heads x seq_length x seq_length
# 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]
head_mask = self.get_head_mask(head_mask)
encoder_outputs = self.encoder(
embedding_output,
bbox=final_bbox,
position_ids=final_position_ids,
attention_mask=extended_attention_mask,
head_mask=head_mask,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
)
sequence_output = encoder_outputs[0]
if not return_dict:
return (sequence_output,) + encoder_outputs[1:]
return TFBaseModelOutput(
last_hidden_state=sequence_output,
hidden_states=encoder_outputs.hidden_states,
attentions=encoder_outputs.attentions,
)
return TFBaseModelOutput(
last_hidden_state=sequence_output,
hidden_states=encoder_outputs.hidden_states,
attentions=encoder_outputs.attentions,
)
class TFLayoutLMv3PreTrainedModel(TFPreTrainedModel):
"""
An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained
models.
"""
config_class = LayoutLMv3Config
base_model_prefix = "layoutlmv3"
@property
def dummy_inputs(self) -> Dict[str, tf.Tensor]:
size = self.config.input_size
image_shape = (2, self.config.num_channels, size, size)
pixel_values = tf.random.uniform(shape=image_shape, minval=-1, maxval=1)
return {
"input_ids": tf.constant(_DUMMY_INPUT_IDS, dtype=tf.int32),
"bbox": tf.constant(_DUMMY_BBOX, dtype=tf.int32),
"pixel_values": pixel_values,
}
@tf.function(
input_signature=[
{