From c135e494b7a49d20b51f9c181f104d9adb0099af Mon Sep 17 00:00:00 2001
From: Chris Dyer <cdyer@cs.cmu.edu>
Date: Thu, 26 May 2011 01:21:44 -0400
Subject: fix bug preventing oovs from firing when they're near the beginning
 of a word

---
 decoder/ff_klm.cc | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/decoder/ff_klm.cc b/decoder/ff_klm.cc
index ab44232a..35b35d36 100644
--- a/decoder/ff_klm.cc
+++ b/decoder/ff_klm.cc
@@ -239,13 +239,14 @@ class KLanguageModelImpl {
 
   // this assumes no target words on final unary -> goal rule.  is that ok?
   // for <s> (n-1 left words) and (n-1 right words) </s>
-  double FinalTraversalCost(const void* state) {
+  double FinalTraversalCost(const void* state, double* oovs) {
     if (add_sos_eos_) {  // rules do not produce <s> </s>, so do it here
       SetRemnantLMState(ngram_->BeginSentenceState(), dummy_state_);
       SetHasFullContext(1, dummy_state_);
       SetUnscoredSize(0, dummy_state_);
       dummy_ants_[1] = state;
-      return LookupWords(*dummy_rule_, dummy_ants_, NULL, NULL, NULL, NULL);
+      *oovs = 0;
+      return LookupWords(*dummy_rule_, dummy_ants_, NULL, oovs, NULL, NULL);
     } else {  // rules DO produce <s> ... </s>
       double p = 0;
       if (!GetFlag(state, HAS_EOS_ON_RIGHT)) { p -= 100; }
@@ -387,6 +388,7 @@ KLanguageModel<Model>::KLanguageModel(const string& param) {
   pimpl_ = new KLanguageModelImpl<Model>(filename, mapfile, explicit_markers);
   fid_ = FD::Convert(featname);
   oov_fid_ = FD::Convert(featname+"_OOV");
+  cerr << "FID: " << oov_fid_ << endl;
   SetStateSize(pimpl_->ReserveStateSize());
 }
 
@@ -421,7 +423,11 @@ void KLanguageModel<Model>::TraversalFeaturesImpl(const SentenceMetadata& /* sme
 template <class Model>
 void KLanguageModel<Model>::FinalTraversalFeatures(const void* ant_state,
                                            SparseVector<double>* features) const {
-  features->set_value(fid_, pimpl_->FinalTraversalCost(ant_state));
+  double oovs = 0;
+  double lm = pimpl_->FinalTraversalCost(ant_state, &oovs);
+  features->set_value(fid_, lm);
+  if (oov_fid_ && oovs)
+    features->set_value(oov_fid_, oovs);
 }
 
 // instantiate templates
-- 
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