/
ClassNLLCriterion.lua
59 lines (55 loc) · 1.62 KB
/
ClassNLLCriterion.lua
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local ClassNLLCriterion, parent = torch.class('nn.ClassNLLCriterion', 'nn.Criterion')
function ClassNLLCriterion:__init(weights)
parent.__init(self)
self.sizeAverage = true
if weights then
assert(weights:dim() == 1, "weights input should be 1-D Tensor")
self.weights = weights
end
end
function ClassNLLCriterion:updateOutput(input, target)
if input:dim() == 1 then
self.output = -input[target]
if self.weights then
self.output = self.output*self.weights[target]
end
elseif input:dim() == 2 then
local output = 0
for i=1,target:size(1) do
if self.weights then
output = output - input[i][target[i]]*self.weights[target[i]]
else
output = output - input[i][target[i]]
end
end
if self.sizeAverage then
output = output / target:size(1)
end
self.output = output
else
error('matrix or vector expected')
end
return self.output
end
function ClassNLLCriterion:updateGradInput(input, target)
self.gradInput:resizeAs(input)
self.gradInput:zero()
if input:dim() == 1 then
self.gradInput[target] = -1
if self.weights then
self.gradInput[target] = self.gradInput[target]*self.weights[target]
end
else
local z = -1
if self.sizeAverage then
z = z / target:size(1)
end
for i=1,target:size(1) do
self.gradInput[i][target[i]] = z
if self.weights then
self.gradInput[i][target[i]] = self.gradInput[i][target[i]]*self.weights[target[i]]
end
end
end
return self.gradInput
end