From 1afea7e6bee5b30afa5e57faa982ae762b0b982c Mon Sep 17 00:00:00 2001
From: nicholas-leonard <nick@nikopia.org>
Date: Wed, 3 Aug 2016 15:43:05 -0400
Subject: [PATCH] fix bigrams gradInput

---
 Bigrams.lua | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Bigrams.lua b/Bigrams.lua
index f27004f..87a079a 100644
--- a/Bigrams.lua
+++ b/Bigrams.lua
@@ -30,6 +30,9 @@ function Bigrams:updateOutput(input)
    
    for i=1,batchsize do
       local am = self.bigrams[input[i]]
+      if not am then
+         error("Missing index "..input[i]..". Only have bigrams for "..#self.bigrams.." words")
+      end
       am:batchdraw(self._output[i])
       self.output[i]:index(am.index, 1, self._output[i])
    end
@@ -38,7 +41,7 @@ function Bigrams:updateOutput(input)
 end
 
 function Bigrams:updateGradInput(input, gradOutput)
-   self.gradInput = torch.type(self.gradInput) == 'torch.LongTensor' or torch.LongTensor()
+   self.gradInput = torch.type(self.gradInput) == 'torch.LongTensor' and self.gradInput or torch.LongTensor()
    self.gradInput:resizeAs(input):fill(0) 
    return self.gradInput
 end