1 files changed, 50 insertions, 0 deletions
diff --git a/contrib/lua-torch/nn/AddConstant.lua b/contrib/lua-torch/nn/AddConstant.lua
new file mode 100644
index 000000000..b686d719c
--- /dev/null
+++ b/contrib/lua-torch/nn/AddConstant.lua
@@ -0,0 +1,50 @@
+local AddConstant, parent = torch.class('nn.AddConstant', 'nn.Module')
+
+function AddConstant:__init(constant_scalar,ip)
+   parent.__init(self)
+   self.constant_scalar = constant_scalar
+
+  -- default for inplace is false
+   self.inplace = ip or false
+   if (ip and type(ip) ~= 'boolean') then
+      error('in-place flag must be boolean')
+   end
+end
+
+function AddConstant:updateOutput(input)
+   assert(type(self.constant_scalar) == 'number' or
+      (torch.isTensor(self.constant_scalar) and input:nDimension() <= 2 and
+      input:size(input:nDimension()) == self.constant_scalar:size(1)),
+      'input is not scalar or doesn\'t match with the dimension of constant!')
+   local tmp
+   if torch.isTensor(self.constant_scalar) and input:nDimension() == 2 then
+      local nOutput = self.constant_scalar:size(1)
+      tmp = self.constant_scalar.new()
+      tmp:resize(1,nOutput)
+      tmp:copy(self.constant_scalar)
+      tmp = tmp:expand(input:size(1),nOutput)
+   else
+      tmp = self.constant_scalar
+   end
+   if self.inplace then
+      input:add(tmp)
+      self.output:set(input)
+   else
+      self.output:resizeAs(input)
+      self.output:copy(input)
+      self.output:add(tmp)
+   end
+   return self.output
+end
+
+function AddConstant:updateGradInput(input, gradOutput)
+   if self.inplace then
+      self.gradInput:set(gradOutput)
+      -- restore previous input value
+      input:add(-self.constant_scalar)
+   else
+      self.gradInput:resizeAs(gradOutput)
+      self.gradInput:copy(gradOutput)
+   end
+   return self.gradInput
+end