diff --git a/contrib/other-builds/moses2/AlignmentInfo.cpp b/contrib/other-builds/moses2/AlignmentInfo.cpp
index a512430eb..1887ca80a 100644
--- a/contrib/other-builds/moses2/AlignmentInfo.cpp
+++ b/contrib/other-builds/moses2/AlignmentInfo.cpp
@@ -18,6 +18,7 @@
 ***********************************************************************/
 #include <algorithm>
 #include <set>
+#include <sstream>
 #include "AlignmentInfo.h"
 #include "legacy/Util2.h"
 #include "util/exception.hh"
@@ -156,13 +157,15 @@ std::vector<size_t> AlignmentInfo::GetSourceIndex2PosMap() const
   return ret;
 }
 
-std::ostream &AlignmentInfo::Debug(std::ostream &out, const System &system) const
+std::string AlignmentInfo::Debug(const System &system) const
 {
+  std::stringstream out;
+
   AlignmentInfo::const_iterator iter;
   for (iter = begin(); iter != end(); ++iter) {
     out << iter->first << "-" << iter->second << " ";
   }
-  return out;
+  return out.str();
 }
 
 }
diff --git a/contrib/other-builds/moses2/AlignmentInfo.h b/contrib/other-builds/moses2/AlignmentInfo.h
index 93971eb32..95969dee1 100644
--- a/contrib/other-builds/moses2/AlignmentInfo.h
+++ b/contrib/other-builds/moses2/AlignmentInfo.h
@@ -94,7 +94,7 @@ public:
            m_nonTermIndexMap == rhs.m_nonTermIndexMap;
   }
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 private:
   //! AlignmentInfo objects should only be created by an AlignmentInfoCollection
diff --git a/contrib/other-builds/moses2/HypothesisBase.h b/contrib/other-builds/moses2/HypothesisBase.h
index 7470ddd19..b007f7b44 100644
--- a/contrib/other-builds/moses2/HypothesisBase.h
+++ b/contrib/other-builds/moses2/HypothesisBase.h
@@ -46,7 +46,7 @@ public:
   virtual SCORE GetFutureScore() const = 0;
   virtual void EvaluateWhenApplied() = 0;
 
-  virtual std::ostream &Debug(std::ostream &out, const System &system) const = 0;
+  virtual std::string Debug(const System &system) const = 0;
 
 protected:
   ManagerBase *m_mgr;
diff --git a/contrib/other-builds/moses2/HypothesisColl.cpp b/contrib/other-builds/moses2/HypothesisColl.cpp
index c02ac12ca..7e0168077 100644
--- a/contrib/other-builds/moses2/HypothesisColl.cpp
+++ b/contrib/other-builds/moses2/HypothesisColl.cpp
@@ -5,12 +5,15 @@
  *      Author: hieu
  */
 #include <iostream>
+#include <sstream>
 #include <algorithm>
 #include <boost/foreach.hpp>
 #include "HypothesisColl.h"
 #include "ManagerBase.h"
 #include "System.h"
 
+using namespace std;
+
 namespace Moses2
 {
 
@@ -124,14 +127,15 @@ void HypothesisColl::Clear()
   m_coll.clear();
 }
 
-std::ostream &HypothesisColl::Debug(std::ostream &out, const System &system) const
+std::string HypothesisColl::Debug(const System &system) const
 {
+  stringstream out;
   BOOST_FOREACH (const HypothesisBase *hypo, m_coll) {
-    hypo->Debug(out, system);
+    out << hypo->Debug(system);
     out << std::endl << std::endl;
   }
 
-  return out;
+  return out.str();
 }
 
 } /* namespace Moses2 */
diff --git a/contrib/other-builds/moses2/HypothesisColl.h b/contrib/other-builds/moses2/HypothesisColl.h
index 9d7859de9..7bd539628 100644
--- a/contrib/other-builds/moses2/HypothesisColl.h
+++ b/contrib/other-builds/moses2/HypothesisColl.h
@@ -63,7 +63,7 @@ public:
       const ManagerBase &mgr,
       ArcLists &arcLists) const;
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 protected:
   _HCType m_coll;
diff --git a/contrib/other-builds/moses2/Phrase.h b/contrib/other-builds/moses2/Phrase.h
index 497d70910..e7d0888a4 100644
--- a/contrib/other-builds/moses2/Phrase.h
+++ b/contrib/other-builds/moses2/Phrase.h
@@ -9,6 +9,7 @@
 
 #include <cstddef>
 #include <string>
+#include <sstream>
 #include <iostream>
 #include "Word.h"
 #include "MemPool.h"
@@ -94,19 +95,19 @@ public:
 
   virtual SubPhrase<WORD> GetSubPhrase(size_t start, size_t size) const = 0;
 
-  virtual std::ostream &Debug(std::ostream &out, const System &system) const
+  virtual std::string Debug(const System &system) const
   {
+    std::stringstream out;
     size_t size = GetSize();
     if (size) {
-      (*this)[0].Debug(out, system);
+      out << (*this)[0].Debug(system);
       for (size_t i = 1; i < size; ++i) {
         const WORD &word = (*this)[i];
-        out << " ";
-        word.Debug(out, system);
+        out << " " << word.Debug(system);
       }
     }
 
-    return out;
+    return out.str();
   }
 
   virtual void OutputToStream(std::ostream &out) const
diff --git a/contrib/other-builds/moses2/PhraseBased/Batch/Stacks.cpp b/contrib/other-builds/moses2/PhraseBased/Batch/Stacks.cpp
index 1bed0c7bd..ac836ecf8 100644
--- a/contrib/other-builds/moses2/PhraseBased/Batch/Stacks.cpp
+++ b/contrib/other-builds/moses2/PhraseBased/Batch/Stacks.cpp
@@ -39,8 +39,9 @@ void Stacks::Init(const Manager &mgr, size_t numStacks)
   }
 }
 
-std::ostream &Stacks::Debug(std::ostream &out, const System &system) const
+std::string Stacks::Debug(const System &system) const
 {
+  stringstream out;
   for (size_t i = 0; i < GetSize(); ++i) {
     const Stack *stack = m_stacks[i];
     if (stack) {
@@ -50,7 +51,7 @@ std::ostream &Stacks::Debug(std::ostream &out, const System &system) const
       out << "N ";
     }
   }
-  return out;
+  return out.str();
 }
 
 void Stacks::Add(Hypothesis *hypo, Recycler<HypothesisBase*> &hypoRecycle,
diff --git a/contrib/other-builds/moses2/PhraseBased/Batch/Stacks.h b/contrib/other-builds/moses2/PhraseBased/Batch/Stacks.h
index 758487713..8cd2d857f 100644
--- a/contrib/other-builds/moses2/PhraseBased/Batch/Stacks.h
+++ b/contrib/other-builds/moses2/PhraseBased/Batch/Stacks.h
@@ -51,7 +51,7 @@ public:
   void Add(Hypothesis *hypo, Recycler<HypothesisBase*> &hypoRecycle,
       ArcLists &arcLists);
 
-  std::ostream & Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 protected:
   const Manager &m_mgr;
diff --git a/contrib/other-builds/moses2/PhraseBased/CubePruningMiniStack/Misc.cpp b/contrib/other-builds/moses2/PhraseBased/CubePruningMiniStack/Misc.cpp
index 6731bb320..53f60554e 100644
--- a/contrib/other-builds/moses2/PhraseBased/CubePruningMiniStack/Misc.cpp
+++ b/contrib/other-builds/moses2/PhraseBased/CubePruningMiniStack/Misc.cpp
@@ -91,10 +91,11 @@ CubeEdge::CubeEdge(Manager &mgr, const Hypotheses &hypos, const InputPath &path,
   estimatedScore = mgr.GetEstimatedScores().CalcEstimatedScore(newBitmap);
 }
 
-std::ostream &CubeEdge::Debug(std::ostream &out, const System &system) const
+std::string CubeEdge::Debug(const System &system) const
 {
+  stringstream out;
   out << newBitmap;
-  return out;
+  return out.str();
 }
 
 bool CubeEdge::SetSeenPosition(const size_t x, const size_t y,
diff --git a/contrib/other-builds/moses2/PhraseBased/CubePruningMiniStack/Misc.h b/contrib/other-builds/moses2/PhraseBased/CubePruningMiniStack/Misc.h
index 65f7259eb..f50ee412f 100644
--- a/contrib/other-builds/moses2/PhraseBased/CubePruningMiniStack/Misc.h
+++ b/contrib/other-builds/moses2/PhraseBased/CubePruningMiniStack/Misc.h
@@ -88,7 +88,7 @@ public:
       SeenPositions &seenPositions,
       std::deque<QueueItem*, MemPoolAllocator<QueueItem*> > &queueItemRecycler);
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 protected:
 
diff --git a/contrib/other-builds/moses2/PhraseBased/Hypothesis.cpp b/contrib/other-builds/moses2/PhraseBased/Hypothesis.cpp
index c97bff0a0..6277099b0 100644
--- a/contrib/other-builds/moses2/PhraseBased/Hypothesis.cpp
+++ b/contrib/other-builds/moses2/PhraseBased/Hypothesis.cpp
@@ -107,8 +107,10 @@ bool Hypothesis::operator==(const Hypothesis &other) const
   return ret;
 }
 
-std::ostream &Hypothesis::Debug(std::ostream &out, const System &system) const
+std::string Hypothesis::Debug(const System &system) const
 {
+  stringstream out;
+
   // coverage
   out << GetBitmap() << " " << GetInputPath().range << " ";
 
@@ -122,12 +124,12 @@ std::ostream &Hypothesis::Debug(std::ostream &out, const System &system) const
   }
 
   // string
-  Debug(out, m_mgr->system);
+  //Debug(out, m_mgr->system);
   out << " ";
   out << "fc=" << GetFutureScore() << " ";
-  GetScores().Debug(out, GetManager().system);
+  out << GetScores().Debug(GetManager().system);
 
-  return out;
+  return out.str();
 }
 
 void Hypothesis::OutputToStream(std::ostream &out) const
@@ -156,7 +158,7 @@ void Hypothesis::OutputToStream(std::ostream &out) const
       out << m_path->range.GetStartPos() << "-" << m_path->range.GetEndPos() << ",";
 
       // score breakdown
-      m_scores->Debug(out, m_mgr->system);
+      out << m_scores->Debug(m_mgr->system);
 
       out << "| ";
     }
diff --git a/contrib/other-builds/moses2/PhraseBased/Hypothesis.h b/contrib/other-builds/moses2/PhraseBased/Hypothesis.h
index a98d20ed2..2affd8e7f 100644
--- a/contrib/other-builds/moses2/PhraseBased/Hypothesis.h
+++ b/contrib/other-builds/moses2/PhraseBased/Hypothesis.h
@@ -67,7 +67,7 @@ public:
     return *m_targetPhrase;
   }
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
   virtual void OutputToStream(std::ostream &out) const;
 
diff --git a/contrib/other-builds/moses2/PhraseBased/InputPath.cpp b/contrib/other-builds/moses2/PhraseBased/InputPath.cpp
index 954a8ceeb..3b133ef9b 100644
--- a/contrib/other-builds/moses2/PhraseBased/InputPath.cpp
+++ b/contrib/other-builds/moses2/PhraseBased/InputPath.cpp
@@ -4,11 +4,14 @@
  *  Created on: 23 Oct 2015
  *      Author: hieu
  */
+#include <sstream>
 #include <boost/foreach.hpp>
 #include "InputPath.h"
 #include "TargetPhrases.h"
 #include "../TranslationModel/PhraseTable.h"
 
+using namespace std;
+
 namespace Moses2
 {
 InputPath::InputPath(MemPool &pool, const SubPhrase<Moses2::Word> &subPhrase,
@@ -42,11 +45,13 @@ const TargetPhrases *InputPath::GetTargetPhrases(const PhraseTable &pt) const
   return targetPhrases[ptInd];
 }
 
-std::ostream &InputPath::Debug(std::ostream &out, const System &system) const
+std::string InputPath::Debug(const System &system) const
 {
+  stringstream out;
+
   out << range << " ";
-  subPhrase.Debug(out, system);
-  return out;
+  out << subPhrase.Debug(system);
+  return out.str();
 }
 
 }
diff --git a/contrib/other-builds/moses2/PhraseBased/InputPath.h b/contrib/other-builds/moses2/PhraseBased/InputPath.h
index 39ae6e0bf..285c9c1df 100644
--- a/contrib/other-builds/moses2/PhraseBased/InputPath.h
+++ b/contrib/other-builds/moses2/PhraseBased/InputPath.h
@@ -33,7 +33,7 @@ public:
     return m_isUsed;
   }
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 protected:
   bool m_isUsed;
diff --git a/contrib/other-builds/moses2/PhraseBased/Manager.cpp b/contrib/other-builds/moses2/PhraseBased/Manager.cpp
index 60dfb5bff..ae5e4a296 100644
--- a/contrib/other-builds/moses2/PhraseBased/Manager.cpp
+++ b/contrib/other-builds/moses2/PhraseBased/Manager.cpp
@@ -232,7 +232,7 @@ std::string Manager::OutputNBest()
 
     if (ok) {
       out << transId << " |||";
-      path->Debug(out, system);
+      out << path->Debug(system);
       out << "\n";
     }
 
diff --git a/contrib/other-builds/moses2/PhraseBased/Normal/Stacks.cpp b/contrib/other-builds/moses2/PhraseBased/Normal/Stacks.cpp
index 211d775fe..2a8e1ca4d 100644
--- a/contrib/other-builds/moses2/PhraseBased/Normal/Stacks.cpp
+++ b/contrib/other-builds/moses2/PhraseBased/Normal/Stacks.cpp
@@ -39,8 +39,9 @@ void Stacks::Init(const Manager &mgr, size_t numStacks)
   }
 }
 
-std::ostream &Stacks::Debug(std::ostream &out, const System &system) const
+std::string Stacks::Debug(const System &system) const
 {
+  stringstream out;
   for (size_t i = 0; i < GetSize(); ++i) {
     const Stack *stack = m_stacks[i];
     if (stack) {
@@ -50,7 +51,7 @@ std::ostream &Stacks::Debug(std::ostream &out, const System &system) const
       out << "N ";
     }
   }
-  return out;
+  return out.str();
 }
 
 void Stacks::Add(Hypothesis *hypo, Recycler<HypothesisBase*> &hypoRecycle,
diff --git a/contrib/other-builds/moses2/PhraseBased/Normal/Stacks.h b/contrib/other-builds/moses2/PhraseBased/Normal/Stacks.h
index e1a73a13c..58626f234 100644
--- a/contrib/other-builds/moses2/PhraseBased/Normal/Stacks.h
+++ b/contrib/other-builds/moses2/PhraseBased/Normal/Stacks.h
@@ -51,7 +51,7 @@ public:
   void Add(Hypothesis *hypo, Recycler<HypothesisBase*> &hypoRecycle,
       ArcLists &arcLists);
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 protected:
   const Manager &m_mgr;
diff --git a/contrib/other-builds/moses2/PhraseBased/Sentence.cpp b/contrib/other-builds/moses2/PhraseBased/Sentence.cpp
index 477ffe7ce..54d9eb428 100644
--- a/contrib/other-builds/moses2/PhraseBased/Sentence.cpp
+++ b/contrib/other-builds/moses2/PhraseBased/Sentence.cpp
@@ -15,10 +15,11 @@ using namespace std;
 
 namespace Moses2
 {
-std::ostream &Sentence::XMLOption::Debug(std::ostream &out, const System &system) const
+std::string Sentence::XMLOption::Debug(const System &system) const
 {
+  stringstream out;
   out << "[" << startPos << "," << phraseSize << "]=" << nodeName;
-  return out;
+  return out.str();
 }
 
 //////////////////////////////////////////////////////////////////////////////
diff --git a/contrib/other-builds/moses2/PhraseBased/Sentence.h b/contrib/other-builds/moses2/PhraseBased/Sentence.h
index 5bffa15d2..09324f993 100644
--- a/contrib/other-builds/moses2/PhraseBased/Sentence.h
+++ b/contrib/other-builds/moses2/PhraseBased/Sentence.h
@@ -30,7 +30,7 @@ public:
     std::string nodeName;
     size_t startPos, phraseSize;
 
-    std::ostream &Debug(std::ostream &out, const System &system) const;
+    std::string Debug(const System &system) const;
 
   };
 
diff --git a/contrib/other-builds/moses2/PhraseBased/TargetPhraseImpl.cpp b/contrib/other-builds/moses2/PhraseBased/TargetPhraseImpl.cpp
index f8ad8474d..62fdc9753 100644
--- a/contrib/other-builds/moses2/PhraseBased/TargetPhraseImpl.cpp
+++ b/contrib/other-builds/moses2/PhraseBased/TargetPhraseImpl.cpp
@@ -5,6 +5,7 @@
  *      Author: hieu
  */
 
+#include <sstream>
 #include <stdlib.h>
 #include "TargetPhraseImpl.h"
 #include "../Scores.h"
@@ -48,12 +49,12 @@ TargetPhraseImpl::~TargetPhraseImpl()
   // TODO Auto-generated destructor stub
 }
 
-std::ostream &TargetPhraseImpl::Debug(std::ostream &out, const System &system) const
+std::string TargetPhraseImpl::Debug(const System &system) const
 {
-  Phrase<Moses2::Word>::Debug(out, system);
-  out << " SCORES:";
-  GetScores().Debug(out, system);
-  return out;
+  stringstream out;
+  out << Phrase<Moses2::Word>::Debug(system);
+  out << " SCORES:" << GetScores().Debug(system);
+  return out.str();
 }
 
 }
diff --git a/contrib/other-builds/moses2/PhraseBased/TargetPhraseImpl.h b/contrib/other-builds/moses2/PhraseBased/TargetPhraseImpl.h
index 3bc1fa94c..2e9f4860a 100644
--- a/contrib/other-builds/moses2/PhraseBased/TargetPhraseImpl.h
+++ b/contrib/other-builds/moses2/PhraseBased/TargetPhraseImpl.h
@@ -35,7 +35,7 @@ public:
 
   virtual ~TargetPhraseImpl();
 
-  virtual std::ostream &Debug(std::ostream &out, const System &system) const;
+  virtual std::string Debug(const System &system) const;
 
 protected:
 };
diff --git a/contrib/other-builds/moses2/PhraseBased/TargetPhrases.cpp b/contrib/other-builds/moses2/PhraseBased/TargetPhrases.cpp
index fee66d005..95fe4316c 100644
--- a/contrib/other-builds/moses2/PhraseBased/TargetPhrases.cpp
+++ b/contrib/other-builds/moses2/PhraseBased/TargetPhrases.cpp
@@ -38,13 +38,14 @@ TargetPhrases::~TargetPhrases()
   // TODO Auto-generated destructor stub
 }
 
-std::ostream &TargetPhrases::Debug(std::ostream &out, const System &system) const
+std::string TargetPhrases::Debug(const System &system) const
 {
+  stringstream out;
   BOOST_FOREACH(const TargetPhrase<Moses2::Word> *tp, *this){
-    tp->Debug(out, system);
+    out << tp->Debug(system);
     out << endl;
   }
-  return out;
+  return out.str();
 }
 
 void TargetPhrases::SortAndPrune(size_t tableLimit)
diff --git a/contrib/other-builds/moses2/PhraseBased/TargetPhrases.h b/contrib/other-builds/moses2/PhraseBased/TargetPhrases.h
index 86d1c03d7..dc975987f 100644
--- a/contrib/other-builds/moses2/PhraseBased/TargetPhrases.h
+++ b/contrib/other-builds/moses2/PhraseBased/TargetPhrases.h
@@ -55,7 +55,7 @@ public:
 
   void SortAndPrune(size_t tableLimit);
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 protected:
   Coll m_coll;
diff --git a/contrib/other-builds/moses2/PhraseBased/TrellisPath.cpp b/contrib/other-builds/moses2/PhraseBased/TrellisPath.cpp
index ecc2fd3aa..b396e47b3 100644
--- a/contrib/other-builds/moses2/PhraseBased/TrellisPath.cpp
+++ b/contrib/other-builds/moses2/PhraseBased/TrellisPath.cpp
@@ -16,10 +16,11 @@ using namespace std;
 namespace Moses2
 {
 
-std::ostream &TrellisNode::Debug(std::ostream &out, const System &system) const
+std::string TrellisNode::Debug(const System &system) const
 {
+  stringstream out;
   out << "arcList=" << arcList->size() << " " << ind;
-  return out;
+  return out.str();
 }
 
 /////////////////////////////////////////////////////////////////////////////////
@@ -75,17 +76,18 @@ SCORE TrellisPath::GetFutureScore() const
   return m_scores->GetTotalScore();
 }
 
-std::ostream &TrellisPath::Debug(std::ostream &out, const System &system) const
+std::string TrellisPath::Debug(const System &system) const
 {
+  stringstream out;
   out << ToString();
   out << "||| ";
 
-  GetScores().Debug(out, system);
+  out << GetScores().Debug(system);
   out << "||| ";
 
   out << GetScores().GetTotalScore();
 
-  return out;
+  return out.str();
 }
 
 std::string TrellisPath::ToString() const
diff --git a/contrib/other-builds/moses2/PhraseBased/TrellisPath.h b/contrib/other-builds/moses2/PhraseBased/TrellisPath.h
index c863ff632..6b1242766 100644
--- a/contrib/other-builds/moses2/PhraseBased/TrellisPath.h
+++ b/contrib/other-builds/moses2/PhraseBased/TrellisPath.h
@@ -34,7 +34,7 @@ public:
     return (*arcList)[ind];
   }
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 };
 
@@ -64,7 +64,7 @@ public:
   }
   SCORE GetFutureScore() const;
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
   std::string ToString() const;
 
   //! create a set of next best paths by wiggling 1 of the node at a time.
diff --git a/contrib/other-builds/moses2/SCFG/ActiveChart.cpp b/contrib/other-builds/moses2/SCFG/ActiveChart.cpp
index 8ace85dcd..f37b8fe31 100644
--- a/contrib/other-builds/moses2/SCFG/ActiveChart.cpp
+++ b/contrib/other-builds/moses2/SCFG/ActiveChart.cpp
@@ -57,14 +57,15 @@ std::vector<const SymbolBindElement*> SymbolBind::GetNTElements() const
   return ret;
 }
 
-std::ostream &SymbolBind::Debug(std::ostream &out, const System &system) const
+std::string SymbolBind::Debug(const System &system) const
 {
+  stringstream out;
   BOOST_FOREACH(const SymbolBindElement &ele, coll) {
     out << "("<< *ele.range;
-    ele.word->Debug(out, system);
+    out << ele.word->Debug(system);
     out << ") ";
   }
-  return out;
+  return out.str();
 }
 
 ////////////////////////////////////////////////////////////////////////////
diff --git a/contrib/other-builds/moses2/SCFG/ActiveChart.h b/contrib/other-builds/moses2/SCFG/ActiveChart.h
index 98a2ddf6b..d8329f4b5 100644
--- a/contrib/other-builds/moses2/SCFG/ActiveChart.h
+++ b/contrib/other-builds/moses2/SCFG/ActiveChart.h
@@ -63,7 +63,7 @@ public:
   bool operator==(const SymbolBind &compare) const
   {  return coll == compare.coll; }
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 };
 
diff --git a/contrib/other-builds/moses2/SCFG/CubePruning/Misc.cpp b/contrib/other-builds/moses2/SCFG/CubePruning/Misc.cpp
index 0ab250107..cebbd2cc1 100644
--- a/contrib/other-builds/moses2/SCFG/CubePruning/Misc.cpp
+++ b/contrib/other-builds/moses2/SCFG/CubePruning/Misc.cpp
@@ -29,15 +29,16 @@ SeenPosition::SeenPosition(MemPool &pool, const SCFG::TargetPhrases *vtps, size_
   }
 }
 
-std::ostream &SeenPosition::Debug(std::ostream &out, const System &system) const
+std::string SeenPosition::Debug(const System &system) const
 {
+  stringstream out;
   out << tps << " " << tpInd << " ";
 
   for (size_t i = 0; i < hypoIndColl.size(); ++i) {
     out << hypoIndColl[i] << " ";
   }
 
-  return out;
+  return out.str();
 }
 
 bool SeenPosition::operator==(const SeenPosition &compare) const
@@ -178,14 +179,15 @@ void QueueItem::CreateNext(
   }
 }
 
-std::ostream &QueueItem::Debug(std::ostream &out, const System &system) const
+std::string QueueItem::Debug(const System &system) const
 {
+  stringstream out;
   out << hypo << " " << &(*tps)[tpInd] << "(" << tps << " " << tpInd << ") ";
   for (size_t i = 0; i < hypoIndColl.size(); ++i) {
     out << hypoIndColl[i] << " ";
   }
 
-  return out;
+  return out.str();
 }
 
 }
diff --git a/contrib/other-builds/moses2/SCFG/CubePruning/Misc.h b/contrib/other-builds/moses2/SCFG/CubePruning/Misc.h
index 435d0babc..2ef18194c 100644
--- a/contrib/other-builds/moses2/SCFG/CubePruning/Misc.h
+++ b/contrib/other-builds/moses2/SCFG/CubePruning/Misc.h
@@ -34,7 +34,7 @@ public:
   bool operator==(const SeenPosition &compare) const;
   size_t hash() const;
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 };
 
@@ -86,7 +86,7 @@ public:
       SeenPositions &seenPositions,
       const SCFG::InputPath &path);
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 protected:
   typedef Vector<const Moses2::HypothesisColl *> HyposColl;
diff --git a/contrib/other-builds/moses2/SCFG/Hypothesis.cpp b/contrib/other-builds/moses2/SCFG/Hypothesis.cpp
index 5450ef768..356af624d 100644
--- a/contrib/other-builds/moses2/SCFG/Hypothesis.cpp
+++ b/contrib/other-builds/moses2/SCFG/Hypothesis.cpp
@@ -131,16 +131,16 @@ void Hypothesis::OutputToStream(std::ostream &out) const
   }
 }
 
-std::ostream &Hypothesis::Debug(std::ostream &out, const System &system) const
+std::string Hypothesis::Debug(const System &system) const
 {
+  stringstream out;
   out << this;
 
   out << " RANGE:";
   out << m_path->range;
 
   // score
-  out << " SCORE:";
-  GetScores().Debug(out, GetManager().system);
+  out << " SCORE:" << GetScores().Debug(GetManager().system);
 
   /*
   out << " m_prevHypos=" << m_prevHypos.size() << " ";
@@ -149,16 +149,16 @@ std::ostream &Hypothesis::Debug(std::ostream &out, const System &system) const
   }
   */
 
-  m_targetPhrase->Debug(out, GetManager().system);
+  out << m_targetPhrase->Debug(GetManager().system);
 
   // recursive
   for (size_t i = 0; i < m_prevHypos.size(); ++i) {
     const Hypothesis &prevHypo = *m_prevHypos[i];
     out << endl;
-    prevHypo.Debug(out, system);
+    out << prevHypo.Debug(system);
   }
 
-  return out;
+  return out.str();
 }
 
 } // namespaces
diff --git a/contrib/other-builds/moses2/SCFG/Hypothesis.h b/contrib/other-builds/moses2/SCFG/Hypothesis.h
index 286baa7da..f32ad94a7 100644
--- a/contrib/other-builds/moses2/SCFG/Hypothesis.h
+++ b/contrib/other-builds/moses2/SCFG/Hypothesis.h
@@ -44,7 +44,7 @@ public:
 
   void OutputToStream(std::ostream &out) const;
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 protected:
   const SCFG::TargetPhraseImpl *m_targetPhrase;
diff --git a/contrib/other-builds/moses2/SCFG/InputPath.cpp b/contrib/other-builds/moses2/SCFG/InputPath.cpp
index 3668a8782..e9e80e5f9 100644
--- a/contrib/other-builds/moses2/SCFG/InputPath.cpp
+++ b/contrib/other-builds/moses2/SCFG/InputPath.cpp
@@ -37,10 +37,11 @@ InputPath::~InputPath()
   // TODO Auto-generated destructor stub
 }
 
-std::ostream &InputPath::Debug(std::ostream &out, const System &system) const
+std::string InputPath::Debug(const System &system) const
 {
+  stringstream out;
   out << range << " ";
-  subPhrase.Debug(out, system);
+  out << subPhrase.Debug(system);
   out << " " << prefixPath << " ";
 
   const Vector<ActiveChartEntry*> &activeEntries = *GetActiveChart(1).entries;
@@ -48,7 +49,7 @@ std::ostream &InputPath::Debug(std::ostream &out, const System &system) const
 
   for (size_t i = 0; i < activeEntries.size(); ++i) {
     const ActiveChartEntry &entry = *activeEntries[i];
-    entry.GetSymbolBind().Debug(out, system);
+    out << entry.GetSymbolBind().Debug(system);
     out << "| ";
   }
 
@@ -59,12 +60,12 @@ std::ostream &InputPath::Debug(std::ostream &out, const System &system) const
   BOOST_FOREACH(const SCFG::InputPath::Coll::value_type &valPair, *targetPhrases) {
     const SymbolBind &symbolBind = valPair.first;
     const SCFG::TargetPhrases &tps = *valPair.second;
-    symbolBind.Debug(out, system);
+    out << symbolBind.Debug(system);
     //out << "=" << tps.GetSize() << " ";
-    tps.Debug(out, system);
+    out << tps.Debug(system);
   }
 
-  return out;
+  return out.str();
 }
 
 void InputPath::AddTargetPhrase(
diff --git a/contrib/other-builds/moses2/SCFG/InputPath.h b/contrib/other-builds/moses2/SCFG/InputPath.h
index 16367b39e..18a6707b5 100644
--- a/contrib/other-builds/moses2/SCFG/InputPath.h
+++ b/contrib/other-builds/moses2/SCFG/InputPath.h
@@ -52,7 +52,7 @@ public:
 
   size_t GetNumRules() const;
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 protected:
   ActiveChart *m_activeChart;
diff --git a/contrib/other-builds/moses2/SCFG/InputPaths.cpp b/contrib/other-builds/moses2/SCFG/InputPaths.cpp
index f5a65c256..e1c3f9d21 100644
--- a/contrib/other-builds/moses2/SCFG/InputPaths.cpp
+++ b/contrib/other-builds/moses2/SCFG/InputPaths.cpp
@@ -67,19 +67,20 @@ void InputPaths::Init(const InputType &input, const ManagerBase &mgr)
 
 }
 
-std::ostream &InputPaths::Debug(std::ostream &out, const System &system) const
+std::string InputPaths::Debug(const System &system) const
 {
+  stringstream out;
   const Matrix<InputPath*> &matrix = GetMatrix();
   for (size_t i = 0; i < matrix.GetRows(); ++i) {
     for (size_t j = 0; j < matrix.GetCols(); ++j) {
       SCFG::InputPath *path = matrix.GetValue(i, j);
       if (path) {
-        path->Debug(out, system);
+        out << path->Debug(system);
         out << endl;
       }
     }
   }
-  return out;
+  return out.str();
 }
 
 }
diff --git a/contrib/other-builds/moses2/SCFG/InputPaths.h b/contrib/other-builds/moses2/SCFG/InputPaths.h
index 3e3c35d06..37e2404cf 100644
--- a/contrib/other-builds/moses2/SCFG/InputPaths.h
+++ b/contrib/other-builds/moses2/SCFG/InputPaths.h
@@ -31,7 +31,7 @@ public:
     return *m_matrix;
   }
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 protected:
   Matrix<InputPath*> *m_matrix;
diff --git a/contrib/other-builds/moses2/SCFG/Manager.cpp b/contrib/other-builds/moses2/SCFG/Manager.cpp
index 4d6888eed..1f228c31a 100644
--- a/contrib/other-builds/moses2/SCFG/Manager.cpp
+++ b/contrib/other-builds/moses2/SCFG/Manager.cpp
@@ -62,9 +62,9 @@ void Manager::Decode()
     cerr << endl << "startPos=" << startPos << endl;
     SCFG::InputPath &initPath = *m_inputPaths.GetMatrix().GetValue(startPos, 0);
 
-    //cerr << "BEFORE path=" << m_inputPaths << endl;
+    cerr << "BEFORE InitActiveChart=" << initPath.Debug(system) << endl;
     InitActiveChart(initPath);
-    cerr << "AFTER path=" << endl;
+    cerr << "AFTER InitActiveChart=" << initPath.Debug(system) << endl;
 
     int maxPhraseSize = inputSize - startPos + 1;
     for (int phraseSize = 1; phraseSize < maxPhraseSize; ++phraseSize) {
@@ -73,14 +73,14 @@ void Manager::Decode()
 
       Stack &stack = m_stacks.GetStack(startPos, phraseSize);
 
-      cerr << "BEFORE LOOKUP path=" << endl;
+      cerr << "BEFORE LOOKUP path=" << path.Debug(system) << endl;
       Lookup(path);
-      cerr << "AFTER LOOKUP path=" << endl;
+      cerr << "AFTER LOOKUP path="  << path.Debug(system) << endl;
       Decode(path, stack);
-      cerr << "AFTER DECODE path=" << endl;
+      cerr << "AFTER DECODE path=" << path.Debug(system) << endl;
 
       LookupUnary(path);
-      //cerr << "AFTER LookupUnary path=" << path << endl;
+      cerr << "AFTER LookupUnary path=" << path.Debug(system) << endl;
 
       //cerr << "#rules=" << path.GetNumRules() << endl;
     }
@@ -317,7 +317,7 @@ std::string Manager::OutputBest() const
 
     bestHypo->OutputToStream(out);
     cerr << "BEST TRANSLATION: ";
-    bestHypo->Debug(cerr, system);
+    cerr << bestHypo->Debug(system);
     cerr << " " << out.str() << endl;
   }
   else {
diff --git a/contrib/other-builds/moses2/SCFG/Stack.cpp b/contrib/other-builds/moses2/SCFG/Stack.cpp
index c019306a2..b1bc58c74 100644
--- a/contrib/other-builds/moses2/SCFG/Stack.cpp
+++ b/contrib/other-builds/moses2/SCFG/Stack.cpp
@@ -104,19 +104,19 @@ const Hypothesis *Stack::GetBestHypo(
   return ret;
 }
 
-std::ostream &Stack::Debug(std::ostream &out, const System &system) const
+std::string Stack::Debug(const System &system) const
 {
+  stringstream out;
   BOOST_FOREACH (const SCFG::Stack::Coll::value_type &valPair, m_coll) {
     const SCFG::Word &lhs = valPair.first;
     const Moses2::HypothesisColl &hypos = *valPair.second;
-    out << "lhs=";
-    lhs.Debug(out, system);
+    out << "lhs=" << lhs.Debug(system);
     out << "=" << hypos.GetSize() << endl;
-    hypos.Debug(out, system);
+    out << hypos.Debug(system);
     out << endl;
   }
 
-  return out;
+  return out.str();
 }
 
 }
diff --git a/contrib/other-builds/moses2/SCFG/Stack.h b/contrib/other-builds/moses2/SCFG/Stack.h
index c54efe0b5..0ecaebfe6 100644
--- a/contrib/other-builds/moses2/SCFG/Stack.h
+++ b/contrib/other-builds/moses2/SCFG/Stack.h
@@ -39,7 +39,7 @@ public:
       const Manager &mgr,
       ArcLists &arcLists) const;
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 protected:
   const Manager &m_mgr;
diff --git a/contrib/other-builds/moses2/SCFG/TargetPhraseImpl.cpp b/contrib/other-builds/moses2/SCFG/TargetPhraseImpl.cpp
index 1fafc182e..d8be4729e 100644
--- a/contrib/other-builds/moses2/SCFG/TargetPhraseImpl.cpp
+++ b/contrib/other-builds/moses2/SCFG/TargetPhraseImpl.cpp
@@ -63,24 +63,23 @@ TargetPhraseImpl::~TargetPhraseImpl()
   // TODO Auto-generated destructor stub
 }
 
-std::ostream &TargetPhraseImpl::Debug(std::ostream &out, const System &system) const
+std::string TargetPhraseImpl::Debug(const System &system) const
 {
-  lhs.Debug(out, system);
+  stringstream out;
+  out << lhs.Debug(system);
   out << " -> ";
   for (size_t i = 0; i < GetSize(); ++i) {
     const SCFG::Word &word = (*this)[i];
-    word.Debug(out, system);
-    out << " ";
+    out << word.Debug(system) << " ";
   }
   out << "pt=" << pt.GetName();
-  out << " SCORES:";
-  GetScores().Debug(out, system);
+  out << " SCORES:" << GetScores().Debug(system);
   out << " ALIGN:";
-  GetAlignTerm().Debug(out, system);
+  out << GetAlignTerm().Debug(system);
   out << " ";
-  GetAlignNonTerm().Debug(out, system);
+  out << GetAlignNonTerm().Debug(system);
 
-  return out;
+  return out.str();
 }
 
 void TargetPhraseImpl::SetAlignmentInfo(const std::string &alignString)
diff --git a/contrib/other-builds/moses2/SCFG/TargetPhraseImpl.h b/contrib/other-builds/moses2/SCFG/TargetPhraseImpl.h
index 960004672..8dbd68fcf 100644
--- a/contrib/other-builds/moses2/SCFG/TargetPhraseImpl.h
+++ b/contrib/other-builds/moses2/SCFG/TargetPhraseImpl.h
@@ -67,7 +67,7 @@ public:
 
   void SetAlignmentInfo(const std::string &alignString);
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
   //mutable void *chartState;
 protected:
diff --git a/contrib/other-builds/moses2/SCFG/TargetPhrases.cpp b/contrib/other-builds/moses2/SCFG/TargetPhrases.cpp
index 0b57bd771..fdcdb4422 100644
--- a/contrib/other-builds/moses2/SCFG/TargetPhrases.cpp
+++ b/contrib/other-builds/moses2/SCFG/TargetPhrases.cpp
@@ -6,6 +6,7 @@
  */
 
 #include <boost/foreach.hpp>
+#include <sstream>
 #include <algorithm>
 #include "TargetPhrases.h"
 #include "TargetPhraseImpl.h"
@@ -49,13 +50,15 @@ void TargetPhrases::SortAndPrune(size_t tableLimit)
   //cerr << "TargetPhrases=" << GetSize() << endl;
 }
 
-std::ostream &TargetPhrases::Debug(std::ostream &out, const System &system) const
+std::string TargetPhrases::Debug(const System &system) const
 {
+  std::stringstream out;
+
   BOOST_FOREACH(const SCFG::TargetPhraseImpl *tp, m_coll) {
     out << std::endl;
-    tp->Debug(out, system);
+    out << tp->Debug(system);
   }
-  return out;
+  return out.str();
 }
 
 }
diff --git a/contrib/other-builds/moses2/SCFG/TargetPhrases.h b/contrib/other-builds/moses2/SCFG/TargetPhrases.h
index ca8b9411f..22502b3ef 100644
--- a/contrib/other-builds/moses2/SCFG/TargetPhrases.h
+++ b/contrib/other-builds/moses2/SCFG/TargetPhrases.h
@@ -55,7 +55,7 @@ public:
 
   void SortAndPrune(size_t tableLimit);
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
 protected:
   Coll m_coll;
diff --git a/contrib/other-builds/moses2/SCFG/Word.cpp b/contrib/other-builds/moses2/SCFG/Word.cpp
index b5a595b5d..2c175709d 100644
--- a/contrib/other-builds/moses2/SCFG/Word.cpp
+++ b/contrib/other-builds/moses2/SCFG/Word.cpp
@@ -75,16 +75,17 @@ void Word::OutputToStream(std::ostream &out) const
   }
 }
 
-std::ostream &Word::Debug(std::ostream &out, const System &system) const
+std::string Word::Debug(const System &system) const
 {
+  stringstream out;
   if (isNonTerminal) {
     out << "[";
   }
-  Moses2::Word::Debug(out, system);
+  out << Moses2::Word::Debug(system);
   if (isNonTerminal) {
       out << "]";
   }
-  return out;
+  return out.str();
 }
 
 }
diff --git a/contrib/other-builds/moses2/SCFG/Word.h b/contrib/other-builds/moses2/SCFG/Word.h
index 4db0b38f8..3e292f458 100644
--- a/contrib/other-builds/moses2/SCFG/Word.h
+++ b/contrib/other-builds/moses2/SCFG/Word.h
@@ -40,7 +40,7 @@ public:
   size_t hash() const;
 
   virtual void OutputToStream(std::ostream &out) const;
-  virtual std::ostream &Debug(std::ostream &out, const System &system) const;
+  virtual std::string Debug(const System &system) const;
 
 protected:
 };
diff --git a/contrib/other-builds/moses2/Scores.cpp b/contrib/other-builds/moses2/Scores.cpp
index 78cdb42d4..3be80f7df 100644
--- a/contrib/other-builds/moses2/Scores.cpp
+++ b/contrib/other-builds/moses2/Scores.cpp
@@ -243,8 +243,9 @@ void Scores::CreateFromString(const std::string &str,
   PlusEquals(system, featureFunction, scores);
 }
 
-std::ostream &Scores::Debug(std::ostream &out, const System &system) const
+std::string Scores::Debug(const System &system) const
 {
+  stringstream out;
   out << "total=" << m_total;
 
   if (system.options.nbest.nbest_size) {
@@ -257,7 +258,7 @@ std::ostream &Scores::Debug(std::ostream &out, const System &system) const
     }
   }
 
-  return out;
+  return out.str();
 }
 
 // static functions to work out estimated scores
diff --git a/contrib/other-builds/moses2/Scores.h b/contrib/other-builds/moses2/Scores.h
index f8f8fd49a..963fb6962 100644
--- a/contrib/other-builds/moses2/Scores.h
+++ b/contrib/other-builds/moses2/Scores.h
@@ -65,7 +65,7 @@ public:
   void Assign(const System &system, const FeatureFunction &featureFunction,
       const std::vector<SCORE> &scores);
 
-  std::ostream &Debug(std::ostream &out, const System &system) const;
+  std::string Debug(const System &system) const;
 
   // static functions to work out estimated scores
   static SCORE CalcWeightedScore(const System &system,
diff --git a/contrib/other-builds/moses2/SubPhrase.h b/contrib/other-builds/moses2/SubPhrase.h
index cc972b06c..5b2cf4f04 100644
--- a/contrib/other-builds/moses2/SubPhrase.h
+++ b/contrib/other-builds/moses2/SubPhrase.h
@@ -1,4 +1,5 @@
 #pragma once
+#include <sstream>
 #include "Phrase.h"
 #include "Word.h"
 #include "SCFG/Word.h"
@@ -29,18 +30,18 @@ public:
     return ret;
   }
 
-  virtual std::ostream &Debug(std::ostream &out, const System &system) const
+  virtual std::string Debug(const System &system) const
   {
+    std::stringstream out;
     if (GetSize()) {
-      (*this)[0].Debug(out, system);
+      out << (*this)[0].Debug(system);
       for (size_t i = 1; i < GetSize(); ++i) {
         const WORD &word = (*this)[i];
-        out << " ";
-        word.Debug(out, system);
+        out << " " << word.Debug(system);
       }
     }
 
-    return out;
+    return out.str();
   }
 
 protected:
diff --git a/contrib/other-builds/moses2/TargetPhrase.h b/contrib/other-builds/moses2/TargetPhrase.h
index 0f237f8de..7e3d8e78e 100644
--- a/contrib/other-builds/moses2/TargetPhrase.h
+++ b/contrib/other-builds/moses2/TargetPhrase.h
@@ -6,6 +6,7 @@
  */
 
 #pragma once
+#include <sstream>
 #include "PhraseImplTemplate.h"
 #include "System.h"
 #include "Scores.h"
@@ -45,13 +46,13 @@ public:
   SCORE *GetScoresProperty(int propertyInd) const
   {    return scoreProperties ? scoreProperties + propertyInd : NULL; }
 
-  virtual std::ostream &Debug(std::ostream &out, const System &system) const
+  virtual std::string Debug(const System &system) const
   {
-    Phrase<WORD>::Debug(out, system);
-    out << " SCORES:";
-    GetScores().Debug(out, system);
+    std::stringstream out;
+    out << Phrase<WORD>::Debug(system);
+    out << " SCORES:" << GetScores().Debug(system);
 
-    return out;
+    return out.str();
   }
 
 protected:
diff --git a/contrib/other-builds/moses2/TranslationModel/ProbingPT.cpp b/contrib/other-builds/moses2/TranslationModel/ProbingPT.cpp
index ce8201153..48d0b43d3 100644
--- a/contrib/other-builds/moses2/TranslationModel/ProbingPT.cpp
+++ b/contrib/other-builds/moses2/TranslationModel/ProbingPT.cpp
@@ -405,7 +405,7 @@ void ProbingPT::InitActiveChart(
     const SCFG::Manager &mgr,
     SCFG::InputPath &path) const
 {
-  cerr << "InitActiveChart=" << path.Debug(cerr, mgr.system) << endl;
+  //cerr << "InitActiveChart=" << path.Debug(cerr, mgr.system) << endl;
   size_t ptInd = GetPtInd();
   ActiveChartEntryProbing *chartEntry = new (pool.Allocate<ActiveChartEntryProbing>()) ActiveChartEntryProbing(pool);
   path.AddActiveChartEntry(ptInd, chartEntry);
@@ -417,7 +417,7 @@ void ProbingPT::Lookup(MemPool &pool,
     const SCFG::Stacks &stacks,
     SCFG::InputPath &path) const
 {
-  cerr << "Lookup=" << endl;
+  //cerr << "Lookup=" << endl;
   if (path.range.GetNumWordsCovered() > maxChartSpan) {
     return;
   }
@@ -521,9 +521,12 @@ void ProbingPT::LookupGivenNode(
     SCFG::InputPath &outPath) const
 {
   std::pair<bool, uint64_t> key = prevEntry.GetKey(wordSought, *this);
+  //cerr << "wordSought=" << wordSought.Debug(cerr, mgr.system) << " " << key.first << endl;
+  cerr << "wordSought=" << wordSought.Debug(mgr.system) << endl;
+  //cerr << "HELLO" << endl;
 
   if (!key.first) {
-    // should only happen when looking up unary rules
+    // should only occasionally happen when looking up unary rules
     return;
   }
 
diff --git a/contrib/other-builds/moses2/Word.cpp b/contrib/other-builds/moses2/Word.cpp
index b6c570863..081e1e489 100644
--- a/contrib/other-builds/moses2/Word.cpp
+++ b/contrib/other-builds/moses2/Word.cpp
@@ -71,8 +71,9 @@ bool Word::operator<(const Word &compare) const
   return (cmp < 0);
 }
 
-std::ostream &Word::Debug(std::ostream &out, const System &system) const
+std::string Word::Debug(const System &system) const
 {
+  stringstream out;
   bool outputAlready = false;
   for (size_t i = 0; i < MAX_NUM_FACTORS; ++i) {
     const Factor *factor = m_factors[i];
@@ -85,7 +86,7 @@ std::ostream &Word::Debug(std::ostream &out, const System &system) const
     }
   }
 
-  return out;
+  return out.str();
 }
 
 void Word::OutputToStream(std::ostream &out) const
diff --git a/contrib/other-builds/moses2/Word.h b/contrib/other-builds/moses2/Word.h
index 23228ea9b..3c6b53592 100644
--- a/contrib/other-builds/moses2/Word.h
+++ b/contrib/other-builds/moses2/Word.h
@@ -53,7 +53,7 @@ public:
   }
 
   virtual void OutputToStream(std::ostream &out) const;
-  virtual std::ostream &Debug(std::ostream &out, const System &system) const;
+  virtual std::string Debug(const System &system) const;
 
   std::string GetString(const FactorList &factorTypes) const;
 protected: