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

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# 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.
# Modified from espnet(https://github.com/espnet/espnet)
"""Subsampling layer definition."""
import paddle
from paddle import nn
from paddlespeech.t2s.modules.transformer.embedding import PositionalEncoding
class Conv2dSubsampling(nn.Layer):
"""Convolutional 2D subsampling (to 1/4 length).
Args:
idim (int): Input dimension.
odim (int): Output dimension.
dropout_rate (float): Dropout rate.
pos_enc (nn.Layer): Custom position encoding layer.
"""
def __init__(self, idim, odim, dropout_rate, pos_enc=None):
"""Construct an Conv2dSubsampling object."""
super().__init__()
self.conv = nn.Sequential(
nn.Conv2D(1, odim, 3, 2),
nn.ReLU(),
nn.Conv2D(odim, odim, 3, 2),
nn.ReLU(), )
self.out = nn.Sequential(
nn.Linear(odim * (((idim - 1) // 2 - 1) // 2), odim),
pos_enc if pos_enc is not None else
PositionalEncoding(odim, dropout_rate), )
def forward(self, x, x_mask):
"""Subsample x.
Args:
x (Tensor): Input tensor (#batch, time, idim).
x_mask (Tensor): Input mask (#batch, 1, time).
Returns:
Tensor: Subsampled tensor (#batch, time', odim), where time' = time // 4.
Tensor: Subsampled mask (#batch, 1, time'), where time' = time // 4.
"""
# (b, c, t, f)
x = x.unsqueeze(1)
x = self.conv(x)
b, c, t, f = paddle.shape(x)
x = self.out(x.transpose([0, 2, 1, 3]).reshape([b, t, c * f]))
if x_mask is None:
return x, None
return x, x_mask[:, :, :-2:2][:, :, :-2:2]
def __getitem__(self, key):
"""Get item.
When reset_parameters() is called, if use_scaled_pos_enc is used,
return the positioning encoding.
"""
if key != -1:
raise NotImplementedError(
"Support only `-1` (for `reset_parameters`).")
return self.out[key]