130 lines
4.3 KiB
Python
130 lines
4.3 KiB
Python
# -*- coding: utf-8 -*-
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"""Residual block module in WaveNet.
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This code is modified from https://github.com/r9y9/wavenet_vocoder.
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"""
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import math
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import torch
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import torch.nn.functional as F
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class Conv1d(torch.nn.Conv1d):
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"""Conv1d module with customized initialization."""
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def __init__(self, *args, **kwargs):
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"""Initialize Conv1d module."""
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super(Conv1d, self).__init__(*args, **kwargs)
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def reset_parameters(self):
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"""Reset parameters."""
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torch.nn.init.kaiming_normal_(self.weight, nonlinearity="relu")
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if self.bias is not None:
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torch.nn.init.constant_(self.bias, 0.0)
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class Conv1d1x1(Conv1d):
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"""1x1 Conv1d with customized initialization."""
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def __init__(self, in_channels, out_channels, bias):
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"""Initialize 1x1 Conv1d module."""
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super(Conv1d1x1, self).__init__(in_channels, out_channels,
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kernel_size=1, padding=0,
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dilation=1, bias=bias)
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class ResidualBlock(torch.nn.Module):
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"""Residual block module in WaveNet."""
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def __init__(self,
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kernel_size=3,
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residual_channels=64,
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gate_channels=128,
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skip_channels=64,
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aux_channels=80,
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dropout=0.0,
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dilation=1,
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bias=True,
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use_causal_conv=False
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):
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"""Initialize ResidualBlock module.
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Args:
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kernel_size (int): Kernel size of dilation convolution layer.
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residual_channels (int): Number of channels for residual connection.
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skip_channels (int): Number of channels for skip connection.
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aux_channels (int): Local conditioning channels i.e. auxiliary input dimension.
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dropout (float): Dropout probability.
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dilation (int): Dilation factor.
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bias (bool): Whether to add bias parameter in convolution layers.
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use_causal_conv (bool): Whether to use use_causal_conv or non-use_causal_conv convolution.
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"""
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super(ResidualBlock, self).__init__()
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self.dropout = dropout
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# no future time stamps available
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if use_causal_conv:
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padding = (kernel_size - 1) * dilation
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else:
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assert (kernel_size - 1) % 2 == 0, "Not support even number kernel size."
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padding = (kernel_size - 1) // 2 * dilation
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self.use_causal_conv = use_causal_conv
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# dilation conv
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self.conv = Conv1d(residual_channels, gate_channels, kernel_size,
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padding=padding, dilation=dilation, bias=bias)
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# local conditioning
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if aux_channels > 0:
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self.conv1x1_aux = Conv1d1x1(aux_channels, gate_channels, bias=False)
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else:
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self.conv1x1_aux = None
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# conv output is split into two groups
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gate_out_channels = gate_channels // 2
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self.conv1x1_out = Conv1d1x1(gate_out_channels, residual_channels, bias=bias)
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self.conv1x1_skip = Conv1d1x1(gate_out_channels, skip_channels, bias=bias)
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def forward(self, x, c):
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"""Calculate forward propagation.
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Args:
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x (Tensor): Input tensor (B, residual_channels, T).
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c (Tensor): Local conditioning auxiliary tensor (B, aux_channels, T).
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Returns:
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Tensor: Output tensor for residual connection (B, residual_channels, T).
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Tensor: Output tensor for skip connection (B, skip_channels, T).
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"""
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residual = x
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x = F.dropout(x, p=self.dropout, training=self.training)
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x = self.conv(x)
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# remove future time steps if use_causal_conv conv
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x = x[:, :, :residual.size(-1)] if self.use_causal_conv else x
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# split into two part for gated activation
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splitdim = 1
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xa, xb = x.split(x.size(splitdim) // 2, dim=splitdim)
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# local conditioning
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if c is not None:
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assert self.conv1x1_aux is not None
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c = self.conv1x1_aux(c)
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ca, cb = c.split(c.size(splitdim) // 2, dim=splitdim)
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xa, xb = xa + ca, xb + cb
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x = torch.tanh(xa) * torch.sigmoid(xb)
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# for skip connection
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s = self.conv1x1_skip(x)
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# for residual connection
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x = (self.conv1x1_out(x) + residual) * math.sqrt(0.5)
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return x, s
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