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#!/usr/bin/env python3 | |
# -*- coding: utf-8 -*- | |
# Copyright 2020 Johns Hopkins University (Shinji Watanabe) | |
# Northwestern Polytechnical University (Pengcheng Guo) | |
# Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0) | |
"""Encoder self-attention layer definition.""" | |
import torch | |
from torch import nn | |
from vec2wav2.models.conformer.layer_norm import LayerNorm | |
class DecoderLayer(nn.Module): | |
"""Encoder layer module. | |
Args: | |
size (int): Input dimension. | |
self_attn (torch.nn.Module): Self-attention module instance. | |
`MultiHeadedAttention` or `RelPositionMultiHeadedAttention` instance | |
can be used as the argument. | |
feed_forward (torch.nn.Module): Feed-forward module instance. | |
`PositionwiseFeedForward`, `MultiLayeredConv1d`, or `Conv1dLinear` instance | |
can be used as the argument. | |
feed_forward_macaron (torch.nn.Module): Additional feed-forward module instance. | |
`PositionwiseFeedForward`, `MultiLayeredConv1d`, or `Conv1dLinear` instance | |
can be used as the argument. | |
conv_module (torch.nn.Module): Convolution module instance. | |
`ConvlutionModule` 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, | |
src_attn, | |
feed_forward, | |
feed_forward_macaron, | |
conv_module, | |
dropout_rate, | |
normalize_before=True, | |
concat_after=False, | |
): | |
"""Construct an EncoderLayer object.""" | |
super(DecoderLayer, self).__init__() | |
self.self_attn = self_attn | |
self.src_attn = src_attn | |
self.feed_forward = feed_forward | |
self.feed_forward_macaron = feed_forward_macaron | |
self.conv_module = conv_module | |
self.norm_ff = LayerNorm(size) # for the FNN module | |
self.norm_mha = LayerNorm(size) # for the MHA module | |
self.norm2 = LayerNorm(size) # for the MHA module | |
if feed_forward_macaron is not None: | |
self.norm_ff_macaron = LayerNorm(size) | |
self.ff_scale = 0.5 | |
else: | |
self.ff_scale = 1.0 | |
if self.conv_module is not None: | |
self.norm_conv = LayerNorm(size) # for the CNN module | |
self.norm_final = LayerNorm(size) # for the final output of the block | |
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) | |
self.concat_linear2 = nn.Linear(size + size, size) | |
def forward(self, x_input, mask, memory, memory_mask, cache=None): | |
"""Compute encoded features. | |
Args: | |
x_input (Union[Tuple, torch.Tensor]): Input tensor w/ or w/o pos emb. | |
- w/ pos emb: Tuple of tensors [(#batch, time, size), (1, time, size)]. | |
- w/o pos emb: Tensor (#batch, time, size). | |
mask (torch.Tensor): Mask tensor for the input (#batch, time). | |
cache (torch.Tensor): Cache tensor of the input (#batch, time - 1, size). | |
Returns: | |
torch.Tensor: Output tensor (#batch, time, size). | |
torch.Tensor: Mask tensor (#batch, time). | |
""" | |
if isinstance(x_input, tuple): | |
x, pos_emb = x_input[0], x_input[1] | |
else: | |
x, pos_emb = x_input, None | |
# whether to use macaron style | |
if self.feed_forward_macaron is not None: | |
residual = x | |
if self.normalize_before: | |
x = self.norm_ff_macaron(x) | |
x = residual + self.ff_scale * self.dropout(self.feed_forward_macaron(x)) | |
if not self.normalize_before: | |
x = self.norm_ff_macaron(x) | |
# multi-headed self-attention module | |
residual = x | |
if self.normalize_before: | |
x = self.norm_mha(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 pos_emb is not None: | |
x_att = self.self_attn(x_q, x, x, pos_emb, mask) | |
else: | |
x_att = self.self_attn(x_q, x, x, mask) | |
if self.concat_after: | |
x_concat = torch.cat((x, x_att), dim=-1) | |
x = residual + self.concat_linear(x_concat) | |
else: | |
x = residual + self.dropout(x_att) | |
if not self.normalize_before: | |
x = self.norm_mha(x) | |
# cross attention | |
residual = x | |
if self.normalize_before: | |
x = self.norm2(x) | |
if self.concat_after: | |
x_concat = torch.cat( | |
(x, self.src_attn(x, memory, memory, memory_mask)), dim=-1 | |
) | |
x = residual + self.concat_linear2(x_concat) | |
else: | |
x = residual + self.dropout(self.src_attn(x, memory, memory, memory_mask)) | |
if not self.normalize_before: | |
x = self.norm2(x) | |
# convolution module | |
if self.conv_module is not None: | |
residual = x | |
if self.normalize_before: | |
x = self.norm_conv(x) | |
x = residual + self.dropout(self.conv_module(x)) | |
if not self.normalize_before: | |
x = self.norm_conv(x) | |
# feed forward module | |
residual = x | |
if self.normalize_before: | |
x = self.norm_ff(x) | |
x = residual + self.ff_scale * self.dropout(self.feed_forward(x)) | |
if not self.normalize_before: | |
x = self.norm_ff(x) | |
if self.conv_module is not None: | |
x = self.norm_final(x) | |
if cache is not None: | |
x = torch.cat([cache, x], dim=1) | |
if pos_emb is not None: | |
return (x, pos_emb), mask, memory, memory_mask | |
return x, mask, memory, memory_mask | |