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30 lines
1.3 KiB
30 lines
1.3 KiB
from fastai.vision import *
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class FeatureLoss(nn.Module):
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def __init__(self, m_feat, layer_ids, layer_wgts):
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super().__init__()
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self.m_feat = m_feat
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self.loss_features = [self.m_feat[i] for i in layer_ids]
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self.hooks = hook_outputs(self.loss_features, detach=False)
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self.wgts = layer_wgts
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self.metric_names = ['pixel', ] + [f'feat_{i}' for i in range(len(layer_ids))
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] + [f'gram_{i}' for i in range(len(layer_ids))]
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def make_features(self, x, clone=False):
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self.m_feat(x)
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return [(o.clone() if clone else o) for o in self.hooks.stored]
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def forward(self, input, target):
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out_feat = self.make_features(target, clone=True)
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in_feat = self.make_features(input)
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self.feat_losses = [base_loss(input, target)]
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self.feat_losses += [base_loss(f_in, f_out) * w
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for f_in, f_out, w in zip(in_feat, out_feat, self.wgts)]
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self.feat_losses += [base_loss(gram_matrix(f_in), gram_matrix(f_out)) * w ** 2 * 5e3
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for f_in, f_out, w in zip(in_feat, out_feat, self.wgts)]
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self.metrics = dict(zip(self.metric_names, self.feat_losses))
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return sum(self.feat_losses)
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def __del__(self): self.hooks.remove()
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