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# Copyright 2020 Johns Hopkins University (Shinji Watanabe) | |
# Northwestern Polytechnical University (Pengcheng Guo) | |
# Apache 2.0 (http://www.apache.org/licenses/LICENSE-2.0) | |
# Adapted by Florian Lux 2021 | |
from torch import nn | |
class ConvolutionModule(nn.Module): | |
""" | |
ConvolutionModule in Conformer model. | |
Args: | |
channels (int): The number of channels of conv layers. | |
kernel_size (int): Kernel size of conv layers. | |
""" | |
def __init__(self, channels, kernel_size, activation=nn.ReLU(), bias=True): | |
super(ConvolutionModule, self).__init__() | |
# kernel_size should be an odd number for 'SAME' padding | |
assert (kernel_size - 1) % 2 == 0 | |
self.pointwise_conv1 = nn.Conv1d(channels, 2 * channels, kernel_size=1, stride=1, padding=0, bias=bias, ) | |
self.depthwise_conv = nn.Conv1d(channels, channels, kernel_size, stride=1, padding=(kernel_size - 1) // 2, groups=channels, bias=bias, ) | |
self.norm = nn.GroupNorm(num_groups=32, num_channels=channels) | |
self.pointwise_conv2 = nn.Conv1d(channels, channels, kernel_size=1, stride=1, padding=0, bias=bias, ) | |
self.activation = activation | |
def forward(self, x): | |
""" | |
Compute convolution module. | |
Args: | |
x (torch.Tensor): Input tensor (#batch, time, channels). | |
Returns: | |
torch.Tensor: Output tensor (#batch, time, channels). | |
""" | |
# exchange the temporal dimension and the feature dimension | |
x = x.transpose(1, 2) | |
# GLU mechanism | |
x = self.pointwise_conv1(x) # (batch, 2*channel, dim) | |
x = nn.functional.glu(x, dim=1) # (batch, channel, dim) | |
# 1D Depthwise Conv | |
x = self.depthwise_conv(x) | |
x = self.activation(self.norm(x)) | |
x = self.pointwise_conv2(x) | |
return x.transpose(1, 2) | |