initial revamp of torch7 tree

1 files changed, 25 insertions, 0 deletions

diff --git a/MarginRankingCriterion.lua b/MarginRankingCriterion.lua
new file mode 100644
index 0000000..a365ade
--- /dev/null
+++ b/MarginRankingCriterion.lua
@@ -0,0 +1,25 @@
+local MarginRankingCriterion, parent = torch.class('nn.MarginRankingCriterion', 'nn.Module')
+
+function MarginRankingCriterion:__init(margin)
+   parent.__init(self)
+   margin=margin or 1
+   self.margin = margin 
+   self.gradInput = {torch.Tensor(1), torch.Tensor(1)}
+end 
+ 
+function MarginRankingCriterion:updateOutput(input,y)
+   self.output=math.max(0, -y*(input[1][1]-input[2][1]) + self.margin  ) 
+   return self.output
+end
+
+function MarginRankingCriterion:updateGradInput(input, y)
+  local dist = -y*(input[1][1]-input[2][1]) + self.margin
+  if dist < 0 then
+     self.gradInput[1][1]=0;
+     self.gradInput[2][1]=0;
+  else	
+     self.gradInput[1][1]=-y
+     self.gradInput[2][1]=y
+  end
+  return self.gradInput 
+end