check that there's no epsilon

moses/TranslationOptionCollectionLattice.cpp

@@ -42,6 +42,8 @@ TranslationOptionCollectionLattice::TranslationOptionCollectionLattice(
     const ConfusionNet::Column &col = input.GetColumn(startPos);
     for (size_t i = 0; i < col.size(); ++i) {
       const Word &word = col[i].first;
+      CHECK(!word.IsEpsilon());
+
       Phrase subphrase;
       subphrase.AddWord(word);
 

moses/Word.cpp

@@ -139,6 +139,14 @@ void Word::OnlyTheseFactors(const FactorMask &factors)
   }
 }
 
+bool Word::IsEpsilon() const
+{
+       const Factor *factor = m_factorArray[0];
+       int compare = factor->GetString().compare(EPSILON);
+
+       return compare == 0;
+}
+
 TO_STRING_BODY(Word);
 
 // friend

moses/Word.h

@@ -103,6 +103,8 @@ public:
     m_isOOV = val;
   }
 
+  bool IsEpsilon() const;
+
   /** add the factors from sourceWord into this representation,
    * NULL elements in sourceWord will be skipped */
   void Merge(const Word &sourceWord);