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PaddleSpeech/paddlespeech/t2s/modules/transformer/encoder_layer.py

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3.8 KiB

# Copyright (c) 2021 PaddlePaddle Authors. 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.
3 years ago
# Modified from espnet(https://github.com/espnet/espnet)
"""Encoder self-attention layer definition."""
import paddle
from paddle import nn
class EncoderLayer(nn.Layer):
"""Encoder layer module.
Parameters
----------
size : int
Input dimension.
self_attn : nn.Layer
Self-attention module instance.
`MultiHeadedAttention` instance can be used as the argument.
feed_forward : nn.Layer
Feed-forward module instance.
`PositionwiseFeedForward`, `MultiLayeredConv1d`, or `Conv1dLinear` instance can be used as the argument.
dropout_rate : float
Dropout rate.
normalize_before : bool
Whether to use layer_norm before the first block.
concat_after : bool
Whether to concat attention layer's input and output.
if True, additional linear will be applied.
i.e. x -> x + linear(concat(x, att(x)))
if False, no additional linear will be applied. i.e. x -> x + att(x)
"""
def __init__(
self,
size,
self_attn,
feed_forward,
dropout_rate,
normalize_before=True,
concat_after=False, ):
"""Construct an EncoderLayer object."""
super().__init__()
self.self_attn = self_attn
self.feed_forward = feed_forward
self.norm1 = nn.LayerNorm(size)
self.norm2 = nn.LayerNorm(size)
self.dropout = nn.Dropout(dropout_rate)
self.size = size
self.normalize_before = normalize_before
self.concat_after = concat_after
if self.concat_after:
self.concat_linear = nn.Linear(size + size, size, bias_attr=True)
def forward(self, x, mask, cache=None):
"""Compute encoded features.
Parameters
----------
x_input : paddle.Tensor
Input tensor (#batch, time, size).
mask : paddle.Tensor
Mask tensor for the input (#batch, time).
cache : paddle.Tensor
Cache tensor of the input (#batch, time - 1, size).
Returns
----------
paddle.Tensor
Output tensor (#batch, time, size).
paddle.Tensor
Mask tensor (#batch, time).
"""
residual = x
if self.normalize_before:
x = self.norm1(x)
if cache is None:
x_q = x
else:
assert cache.shape == (x.shape[0], x.shape[1] - 1, self.size)
x_q = x[:, -1:, :]
residual = residual[:, -1:, :]
mask = None if mask is None else mask[:, -1:, :]
if self.concat_after:
x_concat = paddle.concat(
(x, self.self_attn(x_q, x, x, mask)), axis=-1)
x = residual + self.concat_linear(x_concat)
else:
x = residual + self.dropout(self.self_attn(x_q, x, x, mask))
if not self.normalize_before:
x = self.norm1(x)
residual = x
if self.normalize_before:
x = self.norm2(x)
x = residual + self.dropout(self.feed_forward(x))
if not self.normalize_before:
x = self.norm2(x)
if cache is not None:
x = paddle.concat([cache, x], axis=1)
return x, mask