28 lines
907 B
Lua
28 lines
907 B
Lua
-- ref: https://en.wikipedia.org/wiki/L1_loss
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local L1Criterion, parent = torch.class('w2nn.L1Criterion','nn.Criterion')
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function L1Criterion:__init()
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parent.__init(self)
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self.diff = torch.Tensor()
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self.linear_loss_buff = torch.Tensor()
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end
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function L1Criterion:updateOutput(input, target)
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self.diff:resizeAs(input):copy(input)
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if input:dim() == 1 then
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self.diff[1] = input[1] - target
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else
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for i = 1, input:size(1) do
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self.diff[i]:add(-1, target[i])
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end
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end
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local linear_targets = self.diff
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local linear_loss = self.linear_loss_buff:resizeAs(linear_targets):copy(linear_targets):abs():sum()
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self.output = (linear_loss) / input:nElement()
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return self.output
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end
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function L1Criterion:updateGradInput(input, target)
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local norm = 1.0 / input:nElement()
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self.gradInput:resizeAs(self.diff):copy(self.diff):sign():mul(norm)
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return self.gradInput
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end
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