From 4b3a22b5fc63bce5d7db6d53a587777d7c27ea97 Mon Sep 17 00:00:00 2001
From: Volodymyr Mnih <vlad.mnih@gmail.com>
Date: Fri, 21 Jun 2013 11:36:31 +0100
Subject: Added minibatch support to MarginRankingCriterion and
 PairwiseDistance.

---
 MarginRankingCriterion.lua | 66 +++++++++++++++++++++++++++++++++++++++-------
 PairwiseDistance.lua       | 52 ++++++++++++++++++++++++++++--------
 2 files changed, 97 insertions(+), 21 deletions(-)

diff --git a/MarginRankingCriterion.lua b/MarginRankingCriterion.lua
index ec85fb9..5012c2a 100644
--- a/MarginRankingCriterion.lua
+++ b/MarginRankingCriterion.lua
@@ -8,18 +8,64 @@ function MarginRankingCriterion:__init(margin)
 end 
  
 function MarginRankingCriterion:updateOutput(input,y)
-   self.output=math.max(0, -y*(input[1][1]-input[2][1]) + self.margin  ) 
+   if type(input[1]) == "number" then
+      self.output=math.max(0, -y*(input[1]-input[2]) + self.margin  ) 
+   else
+      if type(self.output) == "number" then
+         self.output = input[1]:clone()
+      end
+      self.output = self.output or input[1]:clone()
+      self.output:resizeAs(input[1])
+      self.output:copy(input[1])
+
+      self.output:add(-1, input[2])
+      self.output:mul(-y)
+      self.output:add(self.margin)
+
+      self.mask = self.mask or self.output:clone()
+      self.mask:resizeAs(self.output)
+      self.mask:copy(self.output)
+
+      self.mask:ge(self.output, 0.0)
+      self.output:cmul(self.mask)
+   end
+
    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 
+   if type(input[1]) == "number" then
+      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
+   else
+      self.dist = self.dist or input[1].new()
+      self.dist = self.dist:resizeAs(input[1]):copy(input[1])
+      local dist = self.dist
+
+      dist:add(-1, input[2])
+      dist:mul(-y)
+      dist:add(self.margin)
+
+      self.mask = self.mask or input[1].new()
+      self.mask = self.mask:resizeAs(input[1]):copy(dist)
+      local mask = self.mask
+
+      mask:ge(dist, 0)
+
+      self.gradInput[1]:resize(dist:size())
+      self.gradInput[2]:resize(dist:size())
+
+      self.gradInput[1]:copy(mask)
+      self.gradInput[1]:mul(-y)
+      self.gradInput[2]:copy(mask)
+      self.gradInput[2]:mul(y)
+
+   end
+   return self.gradInput 
 end
diff --git a/PairwiseDistance.lua b/PairwiseDistance.lua
index 638c58f..f108b97 100644
--- a/PairwiseDistance.lua
+++ b/PairwiseDistance.lua
@@ -5,12 +5,29 @@ function PairwiseDistance:__init(p)
 
    -- state
    self.gradInput = {torch.Tensor(), torch.Tensor()}
-   self.output = torch.Tensor(1)
+   self.output = torch.Tensor()
    self.norm=p
 end 
   
 function PairwiseDistance:updateOutput(input)
-   self.output[1]=input[1]:dist(input[2],self.norm);
+   if input[1]:dim() == 1 then
+      self.output[1]=input[1]:dist(input[2],self.norm)
+   elseif input[1]:dim() == 2 then
+      self.diff = self.diff or input[1].new()
+      self.diff:resizeAs(input[1])
+
+      local diff = self.diff:zero()
+      --local diff = torch.add(input[1], -1, input[2])
+      diff:add(input[1], -1, input[2])
+
+      self.output:resize(input[1]:size(1))
+      self.output:zero()
+      self.output:add(diff:pow(self.norm):sum(2))
+      self.output:pow(1./self.norm)
+   else
+      error('input must be vector or matrix')
+   end
+
    return self.output
 end
 
@@ -20,14 +37,27 @@ local function mathsign(x)
 end
 
 function PairwiseDistance:updateGradInput(input, gradOutput)
-  self.gradInput[1]:resizeAs(input[1]) 
-  self.gradInput[2]:resizeAs(input[2]) 
-  self.gradInput[1]:copy(input[1])
-  self.gradInput[1]:add(-1, input[2])
-  if self.norm==1 then
+   self.gradInput[1]:resize(input[1]:size()) 
+   self.gradInput[2]:resize(input[2]:size()) 
+   self.gradInput[1]:copy(input[1])
+   self.gradInput[1]:add(-1, input[2])
+   if self.norm==1 then
      self.gradInput[1]:apply(mathsign)
-  end
-  self.gradInput[1]:mul(gradOutput[1]);
-  self.gradInput[2]:zero():add(-1, self.gradInput[1])
-  return self.gradInput
+   end
+   if input[1]:dim() == 1 then
+      self.gradInput[1]:mul(gradOutput[1])
+   elseif input[1]:dim() == 2 then
+      self.grad = self.grad or gradOutput.new()
+      self.ones = self.ones or gradOutput.new()
+
+      self.grad:resizeAs(input[1]):zero()
+      self.ones:resize(input[1]:size(2)):fill(1)
+
+      self.grad:addr(gradOutput, self.ones)
+      self.gradInput[1]:cmul(self.grad)
+   else
+      error('input must be vector or matrix')
+   end
+   self.gradInput[2]:zero():add(-1, self.gradInput[1])
+   return self.gradInput
 end
-- 
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