initial revamp of torch7 tree

1 files changed, 76 insertions, 0 deletions

diff --git a/LookupTable.lua b/LookupTable.lua
new file mode 100644
index 0000000..115f19c
--- /dev/null
+++ b/LookupTable.lua
@@ -0,0 +1,76 @@
+local LookupTable, parent = torch.class('nn.LookupTable', 'nn.Module')
+
+LookupTable.__version = 2
+
+function LookupTable:__init(nIndex, ...)
+   parent.__init(self)
+
+   if select('#', ...) == 1 and type(select(1, ...)) ~= "number" then
+      local size = select(1, ...)
+      self.size = torch.LongStorage(#size + 1)
+      for i=1,#size do
+         self.size[i+1] = size[i]
+      end
+   else
+      self.size = torch.LongStorage(select('#', ...)+1)
+      for i=1,select('#',...) do
+         self.size[i+1] = select(i, ...)
+      end
+   end
+
+   self.size[1] = nIndex
+   self.weight = torch.Tensor(self.size)
+   self.gradWeight = torch.Tensor(self.size):zero()
+   self.inputs = {}
+
+   self:reset()
+end
+
+function LookupTable:reset(stdv)
+   stdv = stdv or 1
+   self.weight:apply(function()
+                        return torch.normal(0, stdv)
+                     end)
+end
+
+function LookupTable:updateOutput(input)
+   local nIndex = input:size(1)
+   self.size[1] = nIndex
+   self.output:resize(self.size)
+
+   for i=1,nIndex do
+      self.output:select(1, i):copy(self.weight:select(1, input[i]))
+   end
+
+   return self.output
+end
+
+function LookupTable:zeroGradParameters()
+   for k,_ in pairs(self.inputs) do
+      self.gradWeight:select(1, k):zero()
+   end
+   self.inputs = {}
+end
+
+function LookupTable:accGradParameters(input, gradOutput, scale)
+   for i=1,input:size(1) do
+      local k = input[i]
+      self.inputs[k] = true
+      self.gradWeight:select(1, k):add(scale, gradOutput:select(1, i))
+   end
+end
+
+function LookupTable:accUpdateGradParameters(input, gradOutput, lr)
+   for i=1,input:size(1) do
+      self.weight:select(1, input[i]):add(-lr, gradOutput:select(1, i))
+   end
+end
+
+function LookupTable:updateParameters(learningRate)
+   for k,_ in pairs(self.inputs) do
+      self.weight:select(1, k):add(-learningRate, self.gradWeight:select(1, k))
+   end
+end
+
+-- we do not need to accumulate parameters when sharing
+LookupTable.sharedAccUpdateGradParameters = LookupTable.accUpdateGradParameters