From abd3fe3f822fb07f055473bfda99a9a2ac2cf76d Mon Sep 17 00:00:00 2001
From: Trevor Killeen <killeentm@gmail.com>
Date: Tue, 4 Apr 2017 07:44:48 -0700
Subject: implement for accGradParameters

---
 RNN.lua           | 18 +++++++++++-------
 test/test_rnn.lua |  5 +++++
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/RNN.lua b/RNN.lua
index ca0f9ce..0db5ec4 100644
--- a/RNN.lua
+++ b/RNN.lua
@@ -687,7 +687,7 @@ function RNN:updateGradInput(input, gradOutput)
 end
 
 function RNN:accGradParameters(input, gradOutput, scale)
-    if (self.batchFirst) then
+    if self.batchFirst and not self.inputPacked then
         input = input:transpose(1, 2)
         gradOutput = gradOutput:transpose(1, 2)
         self.output = self.output:transpose(1, 2)
@@ -695,15 +695,19 @@ function RNN:accGradParameters(input, gradOutput, scale)
    scale = scale or 1
    if scale == 0 then return end
    assert(self.dropout == 0 or cudnn.version >= 5103, 'dropout supported only in cudnn 5.1 and above')
-   assert(input:dim() == 3, 'input should have 3 dimensions: seqLength, miniBatch, inputSize')
-   assert(input:size(1) == self.seqLength, 'input has incorrect sequence length!')
-   assert(input:size(2) == self.miniBatch, 'input has incorrect minibatch size!')
-   assert(input:size(3) == self.inputSize, 'input has incorrect size!')
+   if self.inputPacked then
+      assert(input[1]:dim() == 2, 'packed input must have two dimensions: sum(sequence lengths), inputSize')
+   else
+      assert(input:dim() == 3, 'input should have 3 dimensions: seqLength, miniBatch, inputSize')
+      assert(input:size(1) == self.seqLength, 'input has incorrect sequence length!')
+      assert(input:size(2) == self.miniBatch, 'input has incorrect minibatch size!')
+      assert(input:size(3) == self.inputSize, 'input has incorrect size!')
+   end
 
    assert(gradOutput:isSameSizeAs(self.output), 'gradOutput has incorrect size!')
    assert(self.train, 'accGradParameters can only be called when training!')
 
-   local x, dy = self:makeContiguous(input, gradOutput)
+   local x, dy = self:makeContiguous(self.inputPacked and input[1] or input, gradOutput)
    local hx = self.hiddenInput
    local y = self.output
    local dw = self.gradWeight
@@ -759,7 +763,7 @@ function RNN:accGradParameters(input, gradOutput, scale)
                scaleTensor:data())
    end
 
-    if (self.batchFirst) then
+    if self.batchFirst and not self.inputPacked then
         gradOutput = gradOutput:transpose(1, 2)
         self.output = self.output:transpose(1, 2)
     end
diff --git a/test/test_rnn.lua b/test/test_rnn.lua
index 8ad982a..cabac77 100644
--- a/test/test_rnn.lua
+++ b/test/test_rnn.lua
@@ -409,6 +409,8 @@ function rnntest.testVariableLengthSequences()
    local packed = cudnn.RNN:packPaddedSequence(input, lengths)
    local packedOutput = lstm:updateOutput(packed)
    local packedHiddenOutput = lstm.hiddenOutput:clone()
+   -- could use padPackedSequence here, but for testing simplicity, we'll just
+   -- operate on the returned results
 
    local separate = {}
    local hids = {}
@@ -467,6 +469,9 @@ function rnntest.testVariableLengthSequences()
       local diff = torch.csub(igiTestable[sep], packedGradInput[batched]):abs():sum()
       mytester:assert(diff < 1e-7)
    end
+
+   -- Step 3: Basically verify that accGradParameters works for batch
+   lstm:accGradParameters(packed, gradOutput)
 end
 
 mytester = torch.Tester()
-- 
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