95 lines
2.9 KiB
Python
95 lines
2.9 KiB
Python
import torch
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import torch.nn as nn
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from ...utils import check_consistency
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class ResidualBlock(nn.Module):
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"""Residual block base class. Implementation of a residual block.
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.. seealso::
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**Original reference**: He, Kaiming, et al.
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"Deep residual learning for image recognition."
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Proceedings of the IEEE conference on computer vision
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and pattern recognition. 2016..
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<https://arxiv.org/pdf/1512.03385.pdf>`_.
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"""
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def __init__(self, input_dim, output_dim,
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hidden_dim, spectral_norm=False,
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activation=torch.nn.ReLU()):
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"""Residual block constructor
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:param int input_dim: Dimension of the input to pass to the
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feedforward linear layer.
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:param int output_dim: Dimension of the output from the
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residual layer.
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:param int hidden_dim: Hidden dimension for mapping the input
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(first block).
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:param bool spectral_norm: Apply spectral normalization to feedforward
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layers, defaults to False.
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:param torch.nn.Module activation: Cctivation function after first block.
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"""
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super().__init__()
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# check consistency
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check_consistency(spectral_norm, bool)
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check_consistency(input_dim, int)
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check_consistency(output_dim, int)
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check_consistency(hidden_dim, int)
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check_consistency(activation, torch.nn.Module)
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# assign variables
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self._spectral_norm = spectral_norm
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self._input_dim = input_dim
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self._output_dim = output_dim
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self._hidden_dim = hidden_dim
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self._activation = activation
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# create layers
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self.l1 = self._spect_norm(nn.Linear(input_dim, hidden_dim))
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self.l2 = self._spect_norm(nn.Linear(hidden_dim, output_dim))
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self.l3 = self._spect_norm(nn.Linear(input_dim, output_dim))
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def forward(self, x):
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"""Forward pass for residual block layer.
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:param torch.Tensor x: Input tensor for the residual layer.
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:return: Output tensor for the residual layer.
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:rtype: torch.Tensor
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"""
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y = self.activation(self.l1(x))
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y = self.l2(y)
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x = self.l3(x)
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return y + x
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def _spect_norm(self, x):
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"""Perform spectral norm on the layers.
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:param x: A torch.nn.Module Linear layer
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:type x: torch.nn.Module
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:return: The spectral norm of the layer
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:rtype: torch.nn.Module
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"""
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return nn.utils.spectral_norm(x) if self._spectral_norm else x
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@ property
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def spectral_norm(self):
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return self._spectral_norm
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@ property
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def input_dim(self):
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return self._input_dim
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@ property
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def output_dim(self):
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return self._output_dim
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@ property
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def hidden_dim(self):
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return self._hidden_dim
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@ property
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def activation(self):
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return self._activation |