Added context buffering in IOWrapper for context-sensitive decoding.

Unfortunately, this seems to slow things down quite a bit.

1 files changed, 79 insertions, 20 deletions

diff --git a/moses/IOWrapper.cpp b/moses/IOWrapper.cpp
index 57717e880..63c8ab5e0 100644
--- a/moses/IOWrapper.cpp
+++ b/moses/IOWrapper.cpp
@@ -81,13 +81,25 @@ IOWrapper::IOWrapper()
 
   ,m_surpressSingleBestOutput(false)
 
+  , m_look_ahead(0)
+  , m_look_back(0)
+  , m_buffered_ahead(0)
+
   ,spe_src(NULL)
   ,spe_trg(NULL)
   ,spe_aln(NULL)
 {
   const StaticData &staticData = StaticData::Instance();
 
+  // context buffering for context-sensitive decoding
+  m_look_ahead = staticData.GetContextParameters().look_ahead;
+  m_look_back  = staticData.GetContextParameters().look_back;
+  
   m_inputType = staticData.GetInputType();
+
+  UTIL_THROW_IF2((m_look_ahead || m_look_back) && m_inputType != SentenceInput,
+		 "Context-sensitive decoding currently works only with sentence input.");
+  
   m_currentLine = staticData.GetStartTranslationId();
 
   m_inputFactorOrder = &staticData.GetInputFactorOrder();
@@ -239,40 +251,87 @@ IOWrapper::~IOWrapper()
 // }
 
 boost::shared_ptr<InputType>
-IOWrapper::ReadInput()
+IOWrapper::
+GetBufferedInput()
 {
-  boost::shared_ptr<InputType> source;
   switch(m_inputType) {
-  case SentenceInput:
-    source.reset(new Sentence);
-    break;
-  case ConfusionNetworkInput:
-    source.reset(new ConfusionNet);
-    break;
+  case SentenceInput: 
+    return BufferInput<Sentence>(); 
+  case ConfusionNetworkInput: 
+    return BufferInput<ConfusionNet>(); 
   case WordLatticeInput:
-    source.reset(new WordLattice);
-    break;
+    return BufferInput<WordLattice>();
   case TreeInputType:
-    source.reset(new TreeInput);
-    break;
+    return BufferInput<TreeInput>();
   case TabbedSentenceInput:
-    source.reset(new TabbedSentence);
-    break;
+    return BufferInput<TabbedSentence>();
   case ForestInputType:
-    source.reset(new ForestInput);
-    break;
+    return BufferInput<ForestInput>();
   default:
     TRACE_ERR("Unknown input type: " << m_inputType << "\n");
+    return boost::shared_ptr<InputType>();
   }
+  
+}
+
+boost::shared_ptr<InputType>
+IOWrapper::ReadInput()
+{
 #ifdef WITH_THREADS
   boost::lock_guard<boost::mutex> lock(m_lock);
 #endif
-  if (source->Read(*m_inputStream, *m_inputFactorOrder))
-    source->SetTranslationId(m_currentLine++);
-  else
-    source.reset();
+  boost::shared_ptr<InputType> source = GetBufferedInput();
+  if (source) 
+    {
+      source->SetTranslationId(m_currentLine++);
+      this->set_context_for(*source);
+    }
+  m_past_input.push_back(source);
   return source;
 }
 
+void 
+IOWrapper::
+set_context_for(InputType& source)
+{
+  boost::shared_ptr<string> context(new string);
+  list<boost::shared_ptr<InputType> >::iterator m = m_past_input.end();
+  // remove obsolete past input from buffer:
+  if (m_past_input.end() != m_past_input.begin())
+    {
+      for (size_t cnt = 0; cnt < m_look_back && --m != m_past_input.begin();
+	   cnt += (*m)->GetSize());
+      while (m_past_input.begin() != m) m_past_input.pop_front();
+    }
+  // cerr << string(80,'=') << endl;
+  if (m_past_input.size())
+    {
+      m = m_past_input.begin();
+      *context += (*m)->ToString();
+      // cerr << (*m)->ToString() << endl;
+      for (++m; m != m_past_input.end(); ++m)
+	{
+	  // cerr << "\n" << (*m)->ToString() << endl;
+	  *context += string(" ") + (*m)->ToString();
+	}
+      // cerr << string(80,'-') << endl;
+    }
+  // cerr << source.ToString() << endl;
+  if (m_future_input.size())
+    {
+      // cerr << string(80,'-') << endl;
+      for (m = m_future_input.begin(); m != m_future_input.end(); ++m)
+	{
+	  // if (m != m_future_input.begin()) cerr << "\n";
+	  // cerr << (*m)->ToString() << endl;
+	  if (context->size()) *context += " ";
+	  *context += (*m)->ToString();
+	}
+    }
+  // cerr << string(80,'=') << endl;
+  source.SetContext(context);
+}
+
+
 } // namespace