def call(self, inputs):
"""Implements call() for the layer."""
unpacked_inputs = tf_utils.unpack_inputs(inputs)
word_embeddings = unpacked_inputs[0]
token_type_ids = unpacked_inputs[1]
input_shape = tf_utils.get_shape_list(word_embeddings, expected_rank=3)
batch_size = input_shape[0]
seq_length = input_shape[1]
width = input_shape[2]
output = word_embeddings
if self.use_type_embeddings:
flat_token_type_ids = tf.reshape(token_type_ids, [-1])
token_type_embeddings = tf.gather(self.type_embeddings,
flat_token_type_ids)
token_type_embeddings = tf.reshape(token_type_embeddings,
[batch_size, seq_length, width])
output += token_type_embeddings
if self.use_position_embeddings:
position_embeddings = tf.expand_dims(tf.slice(
self.position_embeddings, [0, 0], [seq_length, width]),
axis=0)
output += position_embeddings
output = self.output_layer_norm(output)
output = self.output_dropout(output)
return output
def call(self, inputs):
"""Implements call() for the layer."""
(from_tensor, to_tensor,
attention_mask) = tf_utils.unpack_inputs(inputs)
# Scalar dimensions referenced here:
# B = batch size (number of sequences)
# F = `from_tensor` sequence length
# T = `to_tensor` sequence length
# N = `num_attention_heads`
# H = `size_per_head`
# `query_tensor` = [B, F, N ,H]
query_tensor = self.query_dense(from_tensor)
# `key_tensor` = [B, T, N, H]
key_tensor = self.key_dense(to_tensor)
# `value_tensor` = [B, T, N, H]
value_tensor = self.value_dense(to_tensor)
# Take the dot product between "query" and "key" to get the raw
# attention scores.
attention_scores = tf.einsum("BTNH,BFNH->BNFT", key_tensor,
query_tensor)
attention_scores = tf.multiply(
attention_scores, 1.0 / math.sqrt(float(self.size_per_head)))
if attention_mask is not None:
# `attention_mask` = [B, 1, F, T]
attention_mask = tf.expand_dims(attention_mask, axis=[1])
# 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.
adder = (1.0 - tf.cast(attention_mask,
attention_scores.dtype)) * -10000.0
# Since we are adding it to the raw scores before the softmax, this is
# effectively the same as removing these entirely.
attention_scores += adder
# Normalize the attention scores to probabilities.
# `attention_probs` = [B, N, F, T]
attention_probs = tf.nn.softmax(attention_scores)
# 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.attention_probs_dropout(attention_probs)
# `context_layer` = [B, F, N, H]
context_tensor = tf.einsum("BNFT,BTNH->BFNH", attention_probs,
value_tensor)
return context_tensor
def call(self, inputs, return_all_layers=False):
"""Implements call() for the layer.
Args:
inputs: packed inputs.
return_all_layers: bool, whether to return outputs of all layers inside
encoders.
Returns:
Output tensor of the last layer or a list of output tensors.
"""
unpacked_inputs = tf_utils.unpack_inputs(inputs)
input_tensor = unpacked_inputs[0]
attention_mask = unpacked_inputs[1]
output_tensor = input_tensor
all_layer_outputs = []
for layer in self.layers:
output_tensor = layer(output_tensor, attention_mask)
all_layer_outputs.append(output_tensor)
if return_all_layers:
return all_layer_outputs
return all_layer_outputs[-1]
def call(self, inputs):
"""Implements call() for the layer."""
(input_tensor, attention_mask) = tf_utils.unpack_inputs(inputs)
attention_output = self.attention_layer(from_tensor=input_tensor,
to_tensor=input_tensor,
attention_mask=attention_mask)
attention_output = self.attention_output_dense(attention_output)
attention_output = self.attention_dropout(attention_output)
# Use float32 in keras layer norm and the gelu activation in the
# intermediate dense layer for numeric stability
attention_output = self.attention_layer_norm(input_tensor +
attention_output)
if self.float_type == tf.float16:
attention_output = tf.cast(attention_output, tf.float16)
intermediate_output = self.intermediate_dense(attention_output)
if self.float_type == tf.float16:
intermediate_output = tf.cast(intermediate_output, tf.float16)
layer_output = self.output_dense(intermediate_output)
layer_output = self.output_dropout(layer_output)
# Use float32 in keras layer norm for numeric stability
layer_output = self.output_layer_norm(layer_output + attention_output)
if self.float_type == tf.float16:
layer_output = tf.cast(layer_output, tf.float16)
return layer_output
def call(self, inputs, mode="bert"):
"""Implements call() for the layer.
Args:
inputs: packed input tensors.
mode: string, `bert` or `encoder`.
Returns:
Output tensor of the last layer for BERT training (mode=`bert`) which
is a float Tensor of shape [batch_size, seq_length, hidden_size] or
a list of output tensors for encoder usage (mode=`encoder`).
"""
unpacked_inputs = tf_utils.unpack_inputs(inputs)
input_word_ids = unpacked_inputs[0]
input_mask = unpacked_inputs[1]
input_type_ids = unpacked_inputs[2]
word_embeddings = self.embedding_lookup(input_word_ids)
embedding_tensor = self.embedding_postprocessor(
word_embeddings=word_embeddings, token_type_ids=input_type_ids)
if self.float_type == tf.float16:
embedding_tensor = tf.cast(embedding_tensor, tf.float16)
attention_mask = None
if input_mask is not None:
attention_mask = create_attention_mask_from_input_mask(
input_word_ids, input_mask)
if mode == "encoder":
return self.encoder(embedding_tensor,
attention_mask,
return_all_layers=True)
sequence_output = self.encoder(embedding_tensor, attention_mask)
first_token_tensor = tf.squeeze(sequence_output[:, 0:1, :], axis=1)
pooled_output = self.pooler_transform(first_token_tensor)
return (pooled_output, sequence_output)