requ.lua

require 'nn'

local ReQU = torch.class('nn.ReQU', 'nn.Module')

function ReQU:updateOutput(input)
  -- TODO
  self.output:resizeAs(input):copy(input)
  -- ...something here...
--[[
  if input > 0 then
    self.output = torch.cmul(input,input)
  else 
    self.output:zero()
--]]

  self.output[torch.lt(self.output,0)] = 0
  self.output[torch.gt(self.output,0)] = torch.pow(self.output[torch.gt(self.output,0)],2)
  return self.output
end

function ReQU:updateGradInput(input, gradOutput)
  -- TODO
  self.gradInput:resizeAs(gradOutput):copy(gradOutput)
  -- ...something here...
  local dz_dx = torch.Tensor{}
  dz_dx:resizeAs(input):copy(input)
  dz_dx[torch.lt(dz_dx,0)] = 0
  self.gradInput = gradOutput:cmul(dz_dx)
  return self.gradInput
end