1 files changed, 52 insertions, 0 deletions
diff --git a/contrib/lua-torch/nn/Unsqueeze.lua b/contrib/lua-torch/nn/Unsqueeze.lua
new file mode 100644
index 000000000..2e82a25a0
--- /dev/null
+++ b/contrib/lua-torch/nn/Unsqueeze.lua
@@ -0,0 +1,52 @@
+local Unsqueeze, parent = torch.class('nn.Unsqueeze', 'nn.Module')
+
+local function _assertTensor(t)
+   assert(torch.isTensor(t), "This module only works on tensor")
+end
+
+function Unsqueeze:__init(pos, numInputDims)
+   parent.__init(self)
+   self.pos = pos or error('the position to insert singleton dim not specified')
+   self:setNumInputDims(numInputDims)
+end
+
+function Unsqueeze:setNumInputDims(numInputDims)
+   self.numInputDims = numInputDims
+   return self
+end
+
+function Unsqueeze:updateOutput(input)
+   _assertTensor(input)
+   local actualPos = self:_getActualPosition(input)
+   nn.utils.addSingletonDimension(self.output, input, actualPos)
+   return self.output
+end
+
+function Unsqueeze:updateGradInput(input, gradOutput)
+   _assertTensor(input)
+   _assertTensor(gradOutput)
+   assert(input:nElement() == gradOutput:nElement())
+
+   self.gradInput:view(gradOutput, input:size())
+   return self.gradInput
+end
+
+function Unsqueeze:__tostring__()
+   return torch.type(self)..'(dim ' .. self.pos .. ')'
+end
+
+function Unsqueeze:_getActualPosition(input)
+   -- get valid dimesion offset for batchMode (if any)
+   local inputDim = input:dim() -- data batch dim
+   self.numInputDims = self.numInputDims or inputDim -- feature map dim
+   local offsetDim = inputDim - self.numInputDims
+   assert(offsetDim >= 0, "input feature map dim (numInputDims) must be <= input:dim()")
+
+   -- the actual position; clearer error message for batchMode (if any)
+   local actualPos = self.pos + offsetDim
+   assert(actualPos >= 1 and actualPos <= (inputDim + 1),
+      ("Invalid position: %d. input:dim() is %d, input feature map dim (numInputDims) is %d.")
+      :format(self.pos, inputDim, self.numInputDims)
+   )
+   return actualPos
+end