58 lines
1.8 KiB
Python
58 lines
1.8 KiB
Python
from .modules import *
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from torch.nn.functional import mse_loss
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#######################
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# Basic AE-Implementation
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class VariationalAutoEncoder(AbstractNeuralNetwork, ABC):
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@property
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def name(self):
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return self.__class__.__name__
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def __init__(self, dataParams, **kwargs):
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super(VariationalAutoEncoder, self).__init__()
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self.dataParams = dataParams
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self.latent_dim = kwargs.get('latent_dim', 2)
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self.encoder = Encoder(self.latent_dim, variational=True)
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self.decoder = Decoder(self.latent_dim, self.dataParams['features'], variational=True)
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@staticmethod
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def reparameterize(mu, logvar):
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# Lambda Layer, add gaussian noise
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std = torch.exp(0.5*logvar)
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eps = torch.randn_like(std)
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return mu + eps*std
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def forward(self, batch):
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mu, logvar = self.encoder(batch)
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z = self.reparameterize(mu, logvar)
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repeat = Repeater((batch.shape[0], self.dataParams['size'], -1))
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x_hat = self.decoder(repeat(z))
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return x_hat, mu, logvar
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class VariationalAutoEncoderLightningOverrides:
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@property
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def name(self):
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return self.network.name
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def forward(self, x):
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return self.network.forward(x)
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def training_step(self, x, _):
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x_hat, logvar, mu = self.forward(x)
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BCE = mse_loss(x_hat, x, reduction='mean')
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# see Appendix B from VAE paper:
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# Kingma and Welling. Auto-Encoding Variational Bayes. ICLR, 2014
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# https://arxiv.org/abs/1312.6114
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# 0.5 * sum(1 + log(sigma^2) - mu^2 - sigma^2)
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KLD = -0.5 * torch.sum(1 + logvar - mu.pow(2) - logvar.exp())
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return {'loss': BCE + KLD}
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if __name__ == '__main__':
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raise PermissionError('Get out of here - never run this module')
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