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Running
on
Zero
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# Copyright (c) 2021 Mobvoi Inc (Binbin Zhang, Di Wu)
# 2022 58.com(Wuba) Inc AI Lab.
#
# 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."""
from typing import Tuple, Union
import torch
from wenet.transformer.subsampling import BaseSubsampling
class Conv2dSubsampling2(BaseSubsampling):
"""Convolutional 2D subsampling (to 1/4 length).
Args:
idim (int): Input dimension.
odim (int): Output dimension.
dropout_rate (float): Dropout rate.
"""
def __init__(self, idim: int, odim: int, dropout_rate: float,
pos_enc_class: torch.nn.Module):
"""Construct an Conv2dSubsampling4 object."""
super().__init__()
self.conv = torch.nn.Sequential(torch.nn.Conv2d(1, odim, 3, 2),
torch.nn.ReLU())
self.out = torch.nn.Sequential(
torch.nn.Linear(odim * ((idim - 1) // 2), odim))
self.pos_enc = pos_enc_class
# The right context for every conv layer is computed by:
# (kernel_size - 1) * frame_rate_of_this_layer
self.subsampling_rate = 2
# 2 = (3 - 1) * 1
self.right_context = 2
def forward(
self,
x: torch.Tensor,
x_mask: torch.Tensor,
offset: Union[int, torch.Tensor] = 0
) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
"""Subsample x.
Args:
x (torch.Tensor): Input tensor (#batch, time, idim).
x_mask (torch.Tensor): Input mask (#batch, 1, time).
Returns:
torch.Tensor: Subsampled tensor (#batch, time', odim),
where time' = time // 2.
torch.Tensor: Subsampled mask (#batch, 1, time'),
where time' = time // 2.
torch.Tensor: positional encoding
"""
x = x.unsqueeze(1) # (b, c=1, t, f)
x = self.conv(x)
b, c, t, f = x.size()
x = self.out(x.transpose(1, 2).contiguous().view(b, t, c * f))
x, pos_emb = self.pos_enc(x, offset)
return x, pos_emb, x_mask[:, :, :-2:2]
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