multipass decoding

4 files changed, 208 insertions, 95 deletions

diff --git a/decoder/apply_models.h b/decoder/apply_models.h
index 81fa068e..a85694aa 100644
--- a/decoder/apply_models.h
+++ b/decoder/apply_models.h
@@ -1,6 +1,8 @@
 #ifndef _APPLY_MODELS_H_
 #define _APPLY_MODELS_H_
 
+#include <iostream>
+
 struct ModelSet;
 struct Hypergraph;
 struct SentenceMetadata;
@@ -20,6 +22,14 @@ enum {
   IntersectionConfiguration(exhaustive_t /* t */) : algorithm(0), pop_limit() {}
 };
 
+inline std::ostream& operator<<(std::ostream& os, const IntersectionConfiguration& c) {
+  if (c.algorithm == 0) { os << "FULL"; }
+  else if (c.algorithm == 1) { os << "CUBE:k=" << c.pop_limit; }
+  else if (c.algorithm == 2) { os << "N_ALGORITHMS"; }
+  else os << "OTHER";
+  return os;
+}
+
 void ApplyModelSet(const Hypergraph& in,
                    const SentenceMetadata& smeta,
                    const ModelSet& models,
diff --git a/decoder/decoder.cc b/decoder/decoder.cc
index 25f05d8e..478a1cf3 100644
--- a/decoder/decoder.cc
+++ b/decoder/decoder.cc
@@ -59,7 +59,7 @@ namespace Hack { void MaxTrans(const Hypergraph& in, int beam_size); }
 namespace NgramCache { void Clear(); }
 
 DecoderObserver::~DecoderObserver() {}
-void DecoderObserver::NotifyDecodingStart(const SentenceMetadata& smeta) {}
+void DecoderObserver::NotifyDecodingStart(const SentenceMetadata&) {}
 void DecoderObserver::NotifySourceParseFailure(const SentenceMetadata&) {}
 void DecoderObserver::NotifyTranslationForest(const SentenceMetadata&, Hypergraph*) {}
 void DecoderObserver::NotifyAlignmentFailure(const SentenceMetadata&) {}
@@ -72,7 +72,7 @@ struct ELengthWeightFunction {
   }
 };
 inline void ShowBanner() {
-  cerr << "cdec v1.0 (c) 2009-2010 by Chris Dyer\n";
+  cerr << "cdec v1.0 (c) 2009-2011 by Chris Dyer\n";
 }
 
 inline void show_models(po::variables_map const& conf,ModelSet &ms,char const* header) {
@@ -135,12 +135,40 @@ inline shared_ptr<FsaFeatureFunction> make_fsa_ff(string const& ffp,bool verbose
 }
 #endif
 
+// when the translation forest is first built, it is scored by the features associated
+// with the rules. To add other features (like language models, etc), cdec applies one or
+// more "rescoring passes", which compute new features and optionally apply new weights
+// and then prune the resulting (rescored) hypergraph. All feature values from previous
+// passes are present in future passes (although their weights may change).
+struct RescoringPass {
+  RescoringPass() : density_prune(), beam_prune() {}
+  shared_ptr<ModelSet> models;
+  shared_ptr<IntersectionConfiguration> inter_conf;
+  vector<const FeatureFunction*> ffs;
+  shared_ptr<Weights> w;      // null == use previous weights
+  vector<double> weight_vector;
+  double density_prune;       // 0 == don't density prune
+  double beam_prune;          // 0 == don't beam prune
+};
+
+ostream& operator<<(ostream& os, const RescoringPass& rp) {
+  os << "[num_fn=" << rp.ffs.size();
+  if (rp.inter_conf) { os << " int_alg=" << *rp.inter_conf; }
+  if (rp.w) os << " new_weights";
+  if (rp.density_prune) os << " density_prune=" << rp.density_prune;
+  if (rp.beam_prune) os << " beam_prune=" << rp.beam_prune;
+  os << ']';
+  return os;
+}
+
 struct DecoderImpl {
   DecoderImpl(po::variables_map& conf, int argc, char** argv, istream* cfg);
   ~DecoderImpl();
   bool Decode(const string& input, DecoderObserver*);
   void SetWeights(const vector<double>& weights) {
-    feature_weights = weights;
+    init_weights = weights;
+    for (int i = 0; i < rescoring_passes.size(); ++i)
+      rescoring_passes[i].weight_vector = weights;
   }
   void SetId(int next_sent_id) { sent_id = next_sent_id - 1; }
 
@@ -159,8 +187,8 @@ struct DecoderImpl {
     }
   }
 
-  void forest_stats(Hypergraph &forest,string name,bool show_tree,bool show_features,DenseWeightVector const& feature_weights, bool sd=false) {
-      WeightVector fw(feature_weights);
+  void forest_stats(Hypergraph &forest,string name,bool show_tree,bool show_features,DenseWeightVector const& weights, bool sd=false) {
+      WeightVector fw(weights);
       forest_stats(forest,name,show_tree,show_features,&fw,sd);
   }
 
@@ -252,21 +280,30 @@ struct DecoderImpl {
     }
   } 
 
+  // used to construct the suffix string to get the name of arguments for multiple passes
+  // e.g., the "2" in --weights2
+  static string StringSuffixForRescoringPass(int pass) {
+    if (pass == 0) return "";
+    string ps = "1";
+    assert(pass < 9);
+    ps[0] += pass;
+    return ps;
+  }
+
+  vector<RescoringPass> rescoring_passes;
+
   po::variables_map& conf;
   OracleBleu oracle;
   string formalism;
   shared_ptr<Translator> translator;
-  vector<double> feature_weights;
-  Weights w;
+  Weights w_init_weights;      // used with initial parse
+  vector<double> init_weights; // weights used with initial parse
   vector<shared_ptr<FeatureFunction> > pffs;
-  vector<const FeatureFunction*> late_ffs;
 #ifdef FSA_RESCORING
   CFGOptions cfg_options;
   vector<shared_ptr<FsaFeatureFunction> > fsa_ffs;
   vector<string> fsa_names;
 #endif
-  ModelSet* late_models;
-  IntersectionConfiguration* inter_conf;
   shared_ptr<RandomNumberGenerator<boost::mt19937> > rng;
   int sample_max_trans;
   bool aligner_mode;
@@ -319,44 +356,58 @@ DecoderImpl::DecoderImpl(po::variables_map& conf, int argc, char** argv, istream
         ("input,i",po::value<string>()->default_value("-"),"Source file")
         ("grammar,g",po::value<vector<string> >()->composing(),"Either SCFG grammar file(s) or phrase tables file(s)")
         ("per_sentence_grammar_file", po::value<string>(), "Optional (and possibly not implemented) per sentence grammar file enables all per sentence grammars to be stored in a single large file and accessed by offset")
-        ("weights,w",po::value<string>(),"Feature weights file")
-    ("warn_0_weight","Warn about any feature id that has a 0 weight (this is perfectly safe if you intend 0 weight, though)")
-        ("freeze_feature_set,Z", "Freeze feature set after reading feature weights file")
-        ("feature_function,F",po::value<vector<string> >()->composing(), "Additional feature function(s) (-L for list)")
+        ("list_feature_functions,L","List available feature functions")
+
+        ("weights,w",po::value<string>(),"Feature weights file (initial forest / pass 1)")
+        ("feature_function,F",po::value<vector<string> >()->composing(), "Pass 1 additional feature function(s) (-L for list)")
+        ("intersection_strategy,I",po::value<string>()->default_value("cube_pruning"), "Pass 1 intersection strategy for incorporating finite-state features; values include Cube_pruning, Full")
+        ("density_prune", po::value<double>(), "Pass 1 pruning: keep no more than this many times the number of edges used in the best derivation tree (>=1.0)")
+        ("beam_prune", po::value<double>(), "Pass 1 pruning: Prune paths from scored forest, keep paths within exp(alpha>=0)")
+
+        ("weights2",po::value<string>(),"Optional pass 2")
+        ("feature_function2",po::value<vector<string> >()->composing(), "Optional pass 2")
+        ("intersection_strategy2",po::value<string>()->default_value("cube_pruning"), "Optional pass 2")
+        ("density_prune2", po::value<double>(), "Optional pass 2")
+        ("beam_prune2", po::value<double>(), "Optional pass 2")
+
+        ("weights3",po::value<string>(),"Optional pass 3")
+        ("feature_function3",po::value<vector<string> >()->composing(), "Optional pass 3")
+        ("intersection_strategy3",po::value<string>()->default_value("cube_pruning"), "Optional pass 3")
+        ("density_prune3", po::value<double>(), "Optional pass 3")
+        ("beam_prune3", po::value<double>(), "Optional pass 3")
+
 #ifdef FSA_RESCORING
         ("fsa_feature_function,A",po::value<vector<string> >()->composing(), "Additional FSA feature function(s) (-L for list)")
     ("apply_fsa_by",po::value<string>()->default_value("BU_CUBE"), "Method for applying fsa_feature_functions - BU_FULL BU_CUBE EARLEY") //+ApplyFsaBy::all_names()
 #endif
-        ("list_feature_functions,L","List available feature functions")
         ("add_pass_through_rules,P","Add rules to translate OOV words as themselves")
 	("k_best,k",po::value<int>(),"Extract the k best derivations")
 	("unique_k_best,r", "Unique k-best translation list")
+        ("cubepruning_pop_limit,K",po::value<int>()->default_value(200), "Max number of pops from the candidate heap at each node")
         ("aligner,a", "Run as a word/phrase aligner (src & ref required)")
         ("aligner_use_viterbi", "If run in alignment mode, compute the Viterbi (rather than MAP) alignment")
-        ("intersection_strategy,I",po::value<string>()->default_value("cube_pruning"), "Intersection strategy for incorporating finite-state features; values include Cube_pruning, Full")
-        ("cubepruning_pop_limit,K",po::value<int>()->default_value(200), "Max number of pops from the candidate heap at each node")
         ("goal",po::value<string>()->default_value("S"),"Goal symbol (SCFG & FST)")
+        ("freeze_feature_set,Z", "Freeze feature set after reading feature weights file")
+        ("warn_0_weight","Warn about any feature id that has a 0 weight (this is perfectly safe if you intend 0 weight, though)")
         ("scfg_extra_glue_grammar", po::value<string>(), "Extra glue grammar file (Glue grammars apply when i=0 but have no other span restrictions)")
         ("scfg_no_hiero_glue_grammar,n", "No Hiero glue grammar (nb. by default the SCFG decoder adds Hiero glue rules)")
         ("scfg_default_nt,d",po::value<string>()->default_value("X"),"Default non-terminal symbol in SCFG")
         ("scfg_max_span_limit,S",po::value<int>()->default_value(10),"Maximum non-terminal span limit (except \"glue\" grammar)")
-    ("quiet", "Disable verbose output")
-    ("show_config", po::bool_switch(&show_config), "show contents of loaded -c config files.")
-    ("show_weights", po::bool_switch(&show_weights), "show effective feature weights")
+        ("quiet", "Disable verbose output")
+        ("show_config", po::bool_switch(&show_config), "show contents of loaded -c config files.")
+        ("show_weights", po::bool_switch(&show_weights), "show effective feature weights")
         ("show_joshua_visualization,J", "Produce output compatible with the Joshua visualization tools")
         ("show_tree_structure", "Show the Viterbi derivation structure")
         ("show_expected_length", "Show the expected translation length under the model")
         ("show_partition,z", "Compute and show the partition (inside score)")
         ("show_conditional_prob", "Output the conditional log prob to STDOUT instead of a translation")
         ("show_cfg_search_space", "Show the search space as a CFG")
-    ("show_features","Show the feature vector for the viterbi translation")
-    ("density_prune", po::value<double>(), "Keep no more than this many times the number of edges used in the best derivation tree (>=1.0)")
+        ("show_features","Show the feature vector for the viterbi translation")
         ("coarse_to_fine_beam_prune", po::value<double>(), "Prune paths from coarse parse forest before fine parse, keeping paths within exp(alpha>=0)")
         ("ctf_beam_widen", po::value<double>()->default_value(2.0), "Expand coarse pass beam by this factor if no fine parse is found")
         ("ctf_num_widenings", po::value<int>()->default_value(2), "Widen coarse beam this many times before backing off to full parse")
         ("ctf_no_exhaustive", "Do not fall back to exhaustive parse if coarse-to-fine parsing fails")
-        ("beam_prune", po::value<double>(), "Prune paths from +LM forest, keep paths within exp(alpha>=0)")
-    ("scale_prune_srclen", "scale beams by the input length (in # of tokens; may not be what you want for lattices")
+        ("scale_prune_srclen", "scale beams by the input length (in # of tokens; may not be what you want for lattices")
         ("lextrans_use_null", "Support source-side null words in lexical translation")
         ("lextrans_align_only", "Only used in alignment mode. Limit target words generated by reference")
         ("tagger_tagset,t", po::value<string>(), "(Tagger) file containing tag set")
@@ -488,14 +539,79 @@ DecoderImpl::DecoderImpl(po::variables_map& conf, int argc, char** argv, istream
     exit(1);
   }
 
-  // load feature weights (and possibly freeze feature set)
+  // load initial feature weights (and possibly freeze feature set)
   if (conf.count("weights")) {
-    w.InitFromFile(str("weights",conf));
-    feature_weights.resize(FD::NumFeats());
-    w.InitVector(&feature_weights);
+    w_init_weights.InitFromFile(str("weights",conf));
+    w_init_weights.InitVector(&init_weights);
+    init_weights.resize(FD::NumFeats());
+
     if (show_weights)
-      cerr << "+LM weights: " << WeightVector(feature_weights)<<endl;
+      cerr << "Initial weights: " << WeightVector(init_weights)<<endl;
+  }
+
+  // cube pruning pop-limit: we may want to configure this on a per-pass basis
+  pop_limit = conf["cubepruning_pop_limit"].as<int>();
+
+  // determine the number of rescoring/pruning/weighting passes configured
+  const int MAX_PASSES = 3;
+  for (int pass = 0; pass < MAX_PASSES; ++pass) {
+    string ws = "weights" + StringSuffixForRescoringPass(pass);
+    string ff = "feature_function" + StringSuffixForRescoringPass(pass);
+    string bp = "beam_prune" + StringSuffixForRescoringPass(pass);
+    string dp = "density_prune" + StringSuffixForRescoringPass(pass);
+    bool first_pass_condition = ((pass == 0) && (conf.count(ff) || conf.count(bp) || conf.count(dp)));
+    bool nth_pass_condition = ((pass > 0) && (conf.count(ws) || conf.count(ff) || conf.count(bp) || conf.count(dp)));
+    if (first_pass_condition || nth_pass_condition) {
+      rescoring_passes.push_back(RescoringPass());
+      RescoringPass& rp = rescoring_passes.back();
+      // only configure new weights if pass > 0, otherwise we reuse the initial chart weights
+      if (nth_pass_condition && conf.count(ws)) {
+        rp.w.reset(new Weights);
+        rp.w->InitFromFile(str(ws.c_str(), conf));
+        rp.w->InitVector(&rp.weight_vector);
+      }
+      bool has_stateful = false;
+      if (conf.count(ff)) {
+        vector<string> add_ffs;
+        store_conf(conf,ff,&add_ffs);
+        for (int i = 0; i < add_ffs.size(); ++i) {
+          pffs.push_back(make_ff(add_ffs[i],verbose_feature_functions));
+          FeatureFunction const* p=pffs.back().get();
+          rp.ffs.push_back(p);
+          if (p->IsStateful()) { has_stateful = true; }
+        }
+      }
+      if (conf.count(bp)) { rp.beam_prune = conf[bp].as<double>(); }
+      if (conf.count(dp)) { rp.density_prune = conf[dp].as<double>(); }
+      int palg = (has_stateful ? 1 : 0);  // if there are no stateful featueres, default to FULL
+      string isn = "intersection_strategy" + StringSuffixForRescoringPass(pass);
+      if (LowercaseString(str(isn.c_str(),conf)) == "full") {
+        palg = 0;
+      }
+      rp.inter_conf.reset(new IntersectionConfiguration(palg, pop_limit));
+    } else {
+      break;  // TODO alert user if there are any future configurations
+    }
+  }
+
+  // set up weight vectors since later phases may reuse weights from earlier phases
+  const vector<double>* prev = &init_weights;
+  for (int pass = 0; pass < rescoring_passes.size(); ++pass) {
+    RescoringPass& rp = rescoring_passes[pass];
+    if (!rp.w) { rp.weight_vector = *prev; } else { prev = &rp.weight_vector; }
+    rp.models.reset(new ModelSet(rp.weight_vector, rp.ffs));
+    string ps = "Pass1 "; ps[4] += pass;
+    if (!SILENT) show_models(conf,*rp.models,ps.c_str());
   }
+
+  // show configuration of rescoring passes
+  if (!SILENT) {
+    int num = rescoring_passes.size();
+    cerr << "Configured " << num << " rescoring pass" << (num == 1 ? "" : "es") << endl;
+    for (int pass = 0; pass < num; ++pass)
+      cerr << "  " << rescoring_passes[pass] << endl;
+  }
+
   bool warn0=conf.count("warn_0_weight");
   bool freeze=conf.count("freeze_feature_set");
   bool early_freeze=freeze && !warn0;
@@ -523,18 +639,6 @@ DecoderImpl::DecoderImpl(po::variables_map& conf, int argc, char** argv, istream
   else
     assert(!"error");
 
-  // set up additional scoring features
-  if (conf.count("feature_function") > 0) {
-    vector<string> add_ffs;
-//    const vector<string>& add_ffs = conf["feature_function"].as<vector<string> >();
-    store_conf(conf,"feature_function",&add_ffs);
-    for (int i = 0; i < add_ffs.size(); ++i) {
-      pffs.push_back(make_ff(add_ffs[i],verbose_feature_functions));
-      FeatureFunction const* p=pffs.back().get();
-      late_ffs.push_back(p);
-    }
-  }
-
 #ifdef FSA_RESCORING
   store_conf(conf,"fsa_feature_function",&fsa_names);
   for (int i=0;i<fsa_names.size();++i)
@@ -546,7 +650,7 @@ DecoderImpl::DecoderImpl(po::variables_map& conf, int argc, char** argv, istream
   }
   if (!fsa_ffs.empty()) {
     cerr<<"FSA: ";
-    show_all_features(fsa_ffs,feature_weights,cerr,cerr,true,true);
+    show_all_features(fsa_ffs,init_weights,cerr,cerr,true,true);
   }
 #endif
 
@@ -555,17 +659,6 @@ DecoderImpl::DecoderImpl(po::variables_map& conf, int argc, char** argv, istream
     FD::Freeze(); // this means we can't see the feature names of not-weighted features
   }
 
-  late_models = new ModelSet(feature_weights, late_ffs);
-  if (!SILENT) show_models(conf,*late_models,"late ");
-
-  int palg = 1;
-  if (LowercaseString(str("intersection_strategy",conf)) == "full") {
-    palg = 0;
-    cerr << "Using full intersection (no pruning).\n";
-  }
-  pop_limit=conf["cubepruning_pop_limit"].as<int>();
-  inter_conf = new IntersectionConfiguration(palg, pop_limit);
-
   sample_max_trans = conf.count("max_translation_sample") ?
     conf["max_translation_sample"].as<int>() : 0;
   if (sample_max_trans)
@@ -644,8 +737,7 @@ bool DecoderImpl::Decode(const string& input, DecoderObserver* o) {
   translator->ProcessMarkupHints(smeta.sgml_);
   Timer t("Translation");
   const bool translation_successful =
-    translator->Translate(to_translate, &smeta, feature_weights, &forest);
-  //TODO: modify translator to incorporate all 0-state model scores immediately?
+    translator->Translate(to_translate, &smeta, init_weights, &forest);
   translator->SentenceComplete();
 
   if (!translation_successful) {
@@ -660,7 +752,7 @@ bool DecoderImpl::Decode(const string& input, DecoderObserver* o) {
 
   const bool show_tree_structure=conf.count("show_tree_structure");
   const bool show_features=conf.count("show_features");
-  if (!SILENT) forest_stats(forest,"  -LM forest",show_tree_structure,show_features,feature_weights,oracle.show_derivation);
+  if (!SILENT) forest_stats(forest,"  Init. forest",show_tree_structure,show_features,init_weights,oracle.show_derivation);
   if (conf.count("show_expected_length")) {
     const PRPair<double, double> res =
       Inside<PRPair<double, double>,
@@ -669,53 +761,63 @@ bool DecoderImpl::Decode(const string& input, DecoderObserver* o) {
   }
   if (conf.count("show_partition")) {
     const prob_t z = Inside<prob_t, EdgeProb>(forest);
-    cerr << "  -LM partition     log(Z): " << log(z) << endl;
+    cerr << "  Init. partition     log(Z): " << log(z) << endl;
   }
 
+  for (int pass = 0; pass < rescoring_passes.size(); ++pass) {
+    const RescoringPass& rp = rescoring_passes[pass];
+    const vector<double>& cur_weights = rp.weight_vector;
+    if (!SILENT) cerr << endl << "  RESCORING PASS #" << (pass+1) << " " << rp << endl;
 #ifdef FSA_RESCORING
-  cfg_options.maybe_output_source(forest);
+    cfg_options.maybe_output_source(forest);
 #endif
 
-  bool has_late_models = !late_models->empty();
-  if (has_late_models) {
-    Timer t("Forest rescoring:");
-    late_models->PrepareForInput(smeta);
-    forest.Reweight(feature_weights);
-    Hypergraph lm_forest;
-    ApplyModelSet(forest,
+    string passtr = "Pass1"; passtr[4] += pass;
+    forest.Reweight(cur_weights);
+    const bool has_rescoring_models = !rp.models->empty();
+    if (has_rescoring_models) {
+      Timer t("Forest rescoring:");
+      rp.models->PrepareForInput(smeta);
+      Hypergraph rescored_forest;
+      ApplyModelSet(forest,
                   smeta,
-                  *late_models,
-                  *inter_conf,
-                  &lm_forest);
-    forest.swap(lm_forest);
-    forest.Reweight(feature_weights);
-    if (!SILENT) forest_stats(forest,"  +LM forest",show_tree_structure,show_features,feature_weights,oracle.show_derivation);
-  }
+                  *rp.models,
+                  *rp.inter_conf,
+                  &rescored_forest);
+      forest.swap(rescored_forest);
+      forest.Reweight(cur_weights);
+      if (!SILENT) forest_stats(forest,"  " + passtr +" forest",show_tree_structure,show_features,cur_weights,oracle.show_derivation);
+    }
 
-  maybe_prune(forest,conf,"beam_prune","density_prune","+LM",srclen);
+    string fullbp = "beam_prune" + StringSuffixForRescoringPass(pass);
+    string fulldp = "density_prune" + StringSuffixForRescoringPass(pass);
+    maybe_prune(forest,conf,fullbp.c_str(),fulldp.c_str(),passtr,srclen);
 
 #ifdef FSA_RESCORING
-  HgCFG hgcfg(forest);
-  cfg_options.prepare(hgcfg);
-
-  if (!fsa_ffs.empty()) {
-    Timer t("Target FSA rescoring:");
-    if (!has_late_models)
-      forest.Reweight(feature_weights);
-    Hypergraph fsa_forest;
-    assert(fsa_ffs.size()==1);
-    ApplyFsaBy cfg(str("apply_fsa_by",conf),pop_limit);
-    if (!SILENT) cerr << "FSA rescoring with "<<cfg<<" "<<fsa_ffs[0]->describe()<<endl;
-    ApplyFsaModels(hgcfg,smeta,*fsa_ffs[0],feature_weights,cfg,&fsa_forest);
-    forest.swap(fsa_forest);
-    forest.Reweight(feature_weights);
-    if (!SILENT) forest_stats(forest,"  +FSA forest",show_tree_structure,show_features,feature_weights,oracle.show_derivation);
-  }
+    HgCFG hgcfg(forest);
+    cfg_options.prepare(hgcfg);
+
+    if (!fsa_ffs.empty()) {
+      Timer t("Target FSA rescoring:");
+      if (!has_late_models)
+        forest.Reweight(pass0_weights);
+      Hypergraph fsa_forest;
+      assert(fsa_ffs.size()==1);
+      ApplyFsaBy cfg(str("apply_fsa_by",conf),pop_limit);
+      if (!SILENT) cerr << "FSA rescoring with "<<cfg<<" "<<fsa_ffs[0]->describe()<<endl;
+      ApplyFsaModels(hgcfg,smeta,*fsa_ffs[0],pass0_weights,cfg,&fsa_forest);
+      forest.swap(fsa_forest);
+      forest.Reweight(pass0_weights);
+      if (!SILENT) forest_stats(forest,"  +FSA forest",show_tree_structure,show_features,pass0_weights,oracle.show_derivation);
+    }
 #endif
+  }
+
+  const vector<double>& last_weights = (rescoring_passes.empty() ? init_weights : rescoring_passes.back().weight_vector);
 
   // Oracle Rescoring
   if(get_oracle_forest) {
-    Oracle oc=oracle.ComputeOracle(smeta,&forest,FeatureVector(feature_weights),10,conf["forest_output"].as<std::string>());
+    Oracle oc=oracle.ComputeOracle(smeta,&forest,FeatureVector(last_weights),10,conf["forest_output"].as<std::string>());
     if (!SILENT) cerr << "  +Oracle BLEU forest (nodes/edges): " << forest.nodes_.size() << '/' << forest.edges_.size() << endl;
     if (!SILENT) cerr << "  +Oracle BLEU (paths): " << forest.NumberOfPaths() << endl;
     oc.hope.Print(cerr,"  +Oracle BLEU");
@@ -798,8 +900,8 @@ bool DecoderImpl::Decode(const string& input, DecoderObserver* o) {
 //        if (!SILENT) cerr << "  USING UNIFORM WEIGHTS\n";
 //        for (int i = 0; i < forest.edges_.size(); ++i)
 //          forest.edges_[i].edge_prob_=prob_t::One(); }
-      forest.Reweight(feature_weights);
-      if (!SILENT) forest_stats(forest,"  Constr. forest",show_tree_structure,show_features,feature_weights,oracle.show_derivation);
+      forest.Reweight(last_weights);
+      if (!SILENT) forest_stats(forest,"  Constr. forest",show_tree_structure,show_features,last_weights,oracle.show_derivation);
       if (!SILENT) cerr << "  Constr. VitTree: " << ViterbiFTree(forest) << endl;
       if (conf.count("show_partition")) {
          const prob_t z = Inside<prob_t, EdgeProb>(forest);
@@ -830,7 +932,7 @@ bool DecoderImpl::Decode(const string& input, DecoderObserver* o) {
         const prob_t ref_z = InsideOutside<prob_t, EdgeProb, SparseVector<prob_t>, EdgeFeaturesAndProbWeightFunction>(forest, &ref_exp);
         ref_exp /= ref_z;
 //        if (crf_uniform_empirical)
-//          log_ref_z = ref_exp.dot(feature_weights);
+//          log_ref_z = ref_exp.dot(last_weights);
         log_ref_z = log(ref_z);
         //cerr << "      MODEL LOG Z: " << log_z << endl;
         //cerr << "  EMPIRICAL LOG Z: " << log_ref_z << endl;
diff --git a/decoder/ff.h b/decoder/ff.h
index e470f9a9..89b8b067 100644
--- a/decoder/ff.h
+++ b/decoder/ff.h
@@ -40,6 +40,7 @@ class FeatureFunction {
   FeatureFunction() : state_size_() {}
   explicit FeatureFunction(int state_size) : state_size_(state_size) {}
   virtual ~FeatureFunction();
+  bool IsStateful() const { return state_size_ > 0; }
 
   // override this.  not virtual because we want to expose this to factory template for help before creating a FF
   static std::string usage(bool show_params,bool show_details) {
diff --git a/decoder/scfg_translator.cc b/decoder/scfg_translator.cc
index a19e9d75..0f7e40bd 100644
--- a/decoder/scfg_translator.cc
+++ b/decoder/scfg_translator.cc
@@ -124,10 +124,10 @@ struct SCFGTranslatorImpl {
     if (!SILENT) cerr << "First pass parse... " << endl;
     ExhaustiveBottomUpParser parser(goal, glist);
     if (!parser.Parse(lattice, forest)){
-      if (!SILENT) cerr << "parse failed." << endl;
+      if (!SILENT) cerr << "  parse failed." << endl;
       return false;
     } else {
-      if (!SILENT) cerr << "parse succeeded." << endl;
+      // if (!SILENT) cerr << "  parse succeeded." << endl;
     }
     forest->Reweight(weights);
     if (use_ctf_) {