Make CMaxTable and CMinTable cunn-compatible (#954)

Author: Jonathan Uesato

CMaxTable.lua

@@ -4,25 +4,38 @@ function CMaxTable:__init()
    parent.__init(self)
    self.gradInput = {}
    self.maxIdx = torch.Tensor()
+   self.mask = torch.Tensor()
+   self.maxVals = torch.Tensor()
+   self.gradMaxVals = torch.Tensor()
 end
 
 function CMaxTable:updateOutput(input)
    self.output:resizeAs(input[1]):copy(input[1])
    self.maxIdx:resizeAs(input[1]):fill(1)
    for i=2,#input do
-      local mask = torch.gt(input[i], self.output)
-      self.maxIdx:maskedFill(mask, i)
-      self.output:maskedCopy(mask, input[i][mask])
+      self.maskByteTensor = self.maskByteTensor or
+         (torch.type(self.output) == 'torch.CudaTensor' and
+         torch.CudaByteTensor() or torch.ByteTensor())
+      self.mask:gt(input[i], self.output)
+      self.maskByteTensor:resize(self.mask:size()):copy(self.mask)
+      self.maxIdx:maskedFill(self.maskByteTensor, i)
+      self.maxVals:maskedSelect(input[i], self.maskByteTensor)
+      self.output:maskedCopy(self.maskByteTensor, self.maxVals)
    end
    return self.output
 end
 
 function CMaxTable:updateGradInput(input, gradOutput)
    for i=1,#input do
-      self.gradInput[i] = input[i].new()
+      self.gradInput[i] = self.gradInput[i] or input[i].new()
       self.gradInput[i]:resizeAs(input[i]):fill(0.0)
-      local mask = torch.eq(self.maxIdx, i)
-      self.gradInput[i]:maskedCopy(mask, gradOutput[mask])
+      self.maskByteTensor = self.maskByteTensor or
+         (torch.type(self.output) == 'torch.CudaTensor' and
+         torch.CudaByteTensor() or torch.ByteTensor())
+      self.mask:eq(self.maxIdx, i)
+      self.maskByteTensor:resize(self.mask:size()):copy(self.mask)
+      self.gradMaxVals:maskedSelect(gradOutput, self.maskByteTensor)
+      self.gradInput[i]:maskedCopy(self.maskByteTensor, self.gradMaxVals)
    end
 
    for i=#input+1, #self.gradInput do

CMinTable.lua

@@ -4,25 +4,38 @@ function CMinTable:__init()
    parent.__init(self)
    self.gradInput = {}
    self.minIdx = torch.Tensor()
+   self.mask = torch.Tensor()
+   self.minVals = torch.Tensor()
+   self.gradMaxVals = torch.Tensor()
 end
 
 function CMinTable:updateOutput(input)
    self.output:resizeAs(input[1]):copy(input[1])
    self.minIdx:resizeAs(input[1]):fill(1)
    for i=2,#input do
-      local mask = torch.lt(input[i], self.output)
-      self.minIdx:maskedFill(mask, i)
-      self.output:maskedCopy(mask, input[i][mask])
+      self.maskByteTensor = self.maskByteTensor or
+         (torch.type(self.output) == 'torch.CudaTensor' and
+         torch.CudaByteTensor() or torch.ByteTensor())
+      self.mask:lt(input[i], self.output)
+      self.maskByteTensor:resize(self.mask:size()):copy(self.mask)
+      self.minIdx:maskedFill(self.maskByteTensor, i)
+      self.minVals:maskedSelect(input[i], self.maskByteTensor)
+      self.output:maskedCopy(self.maskByteTensor, self.minVals)
    end
    return self.output
 end
 
 function CMinTable:updateGradInput(input, gradOutput)
    for i=1,#input do
-      self.gradInput[i] = torch.Tensor()
+      self.gradInput[i] = self.gradInput[i] or input[i].new()
       self.gradInput[i]:resizeAs(input[i]):fill(0.0)
-      local mask = torch.eq(self.minIdx, i)
-      self.gradInput[i]:maskedCopy(mask, gradOutput[mask])
+      self.maskByteTensor = self.maskByteTensor or
+         (torch.type(self.output) == 'torch.CudaTensor' and
+         torch.CudaByteTensor() or torch.ByteTensor())
+      self.mask:eq(self.minIdx, i)
+      self.maskByteTensor:resize(self.mask:size()):copy(self.mask)
+      self.gradMaxVals:maskedSelect(gradOutput, self.maskByteTensor)
+      self.gradInput[i]:maskedCopy(self.maskByteTensor, self.gradMaxVals)
    end
 
    for i=#input+1, #self.gradInput do