initial checkin

git-svn-id: https://ws10smt.googlecode.com/svn/trunk@2 ec762483-ff6d-05da-a07a-a48fb63a330f

1 files changed, 518 insertions, 0 deletions

diff --git a/vest/ter.cc b/vest/ter.cc
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--- /dev/null
+++ b/vest/ter.cc
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+#include "ter.h"
+
+#include <cstdio>
+#include <cassert>
+#include <iostream>
+#include <limits>
+#include <sstream>
+#include <tr1/unordered_map>
+#include <set>
+#include <valarray>
+#include <boost/functional/hash.hpp>
+
+#include "tdict.h"
+
+const bool ter_use_average_ref_len = true;
+const int ter_short_circuit_long_sentences = -1;
+
+using namespace std;
+using namespace std::tr1;
+
+struct COSTS {
+  static const float substitution;
+  static const float deletion;
+  static const float insertion;
+  static const float shift;
+};
+const float COSTS::substitution = 1.0f;
+const float COSTS::deletion = 1.0f;
+const float COSTS::insertion = 1.0f;
+const float COSTS::shift = 1.0f;
+
+static const int MAX_SHIFT_SIZE = 10;
+static const int MAX_SHIFT_DIST = 50;
+
+struct Shift {
+  unsigned int d_;
+  Shift() : d_() {}
+  Shift(int b, int e, int m) : d_() {
+    begin(b);
+    end(e);
+    moveto(m);
+  }
+  inline int begin() const {
+    return d_ & 0x3ff;
+  }
+  inline int end() const {
+    return (d_ >> 10) & 0x3ff;
+  }
+  inline int moveto() const {
+    int m = (d_ >> 20) & 0x7ff;
+    if (m > 1024) { m -= 1024; m *= -1; }
+    return m;
+  }
+  inline void begin(int b) {
+    d_ &= 0xfffffc00u;
+    d_ |= (b & 0x3ff);
+  }
+  inline void end(int e) {
+    d_ &= 0xfff003ffu;
+    d_ |= (e & 0x3ff) << 10;
+  }
+  inline void moveto(int m) {
+    bool neg = (m < 0);
+    if (neg) { m *= -1; m += 1024; }
+    d_ &= 0xfffff;
+    d_ |= (m & 0x7ff) << 20;
+  }
+};
+
+class TERScorerImpl {
+
+ public:
+  enum TransType { MATCH, SUBSTITUTION, INSERTION, DELETION };
+
+  explicit TERScorerImpl(const vector<WordID>& ref) : ref_(ref) {
+    for (int i = 0; i < ref.size(); ++i)
+      rwexists_.insert(ref[i]);
+  }
+
+  float Calculate(const vector<WordID>& hyp, int* subs, int* ins, int* dels, int* shifts) const {
+    return CalculateAllShifts(hyp, subs, ins, dels, shifts);
+  }
+
+  inline int GetRefLength() const {
+    return ref_.size();
+  }
+
+ private:
+  vector<WordID> ref_;
+  set<WordID> rwexists_;
+
+  typedef unordered_map<vector<WordID>, set<int>, boost::hash<vector<WordID> > > NgramToIntsMap;
+  mutable NgramToIntsMap nmap_;
+ 
+  static float MinimumEditDistance(
+      const vector<WordID>& hyp,
+      const vector<WordID>& ref,
+      vector<TransType>* path) {
+    vector<vector<TransType> > bmat(hyp.size() + 1, vector<TransType>(ref.size() + 1, MATCH));
+    vector<vector<float> > cmat(hyp.size() + 1, vector<float>(ref.size() + 1, 0));
+    for (int i = 0; i <= hyp.size(); ++i)
+      cmat[i][0] = i;
+    for (int j = 0; j <= ref.size(); ++j)
+      cmat[0][j] = j;
+    for (int i = 1; i <= hyp.size(); ++i) {
+      const WordID& hw = hyp[i-1];
+      for (int j = 1; j <= ref.size(); ++j) {
+        const WordID& rw = ref[j-1];
+	float& cur_c = cmat[i][j];
+	TransType& cur_b = bmat[i][j];
+
+        if (rw == hw) {
+          cur_c = cmat[i-1][j-1];
+          cur_b = MATCH;
+        } else {
+          cur_c = cmat[i-1][j-1] + COSTS::substitution;
+          cur_b = SUBSTITUTION;
+        }
+	float cwoi = cmat[i-1][j];
+        if (cur_c > cwoi + COSTS::insertion) {
+          cur_c = cwoi + COSTS::insertion;
+          cur_b = INSERTION;
+        }
+        float cwod = cmat[i][j-1];
+        if (cur_c > cwod + COSTS::deletion) {
+          cur_c = cwod + COSTS::deletion;
+          cur_b = DELETION;
+        }
+      }
+    }
+    
+    // trace back along the best path and record the transition types
+    path->clear();
+    int i = hyp.size();
+    int j = ref.size();
+    while (i > 0 || j > 0) {
+      if (j == 0) {
+        --i;
+        path->push_back(INSERTION);
+      } else if (i == 0) {
+        --j;
+        path->push_back(DELETION);
+      } else {
+        TransType t = bmat[i][j];
+        path->push_back(t);
+        switch (t) {
+          case SUBSTITUTION:
+          case MATCH:
+            --i; --j; break;
+          case INSERTION:
+            --i; break;
+          case DELETION:
+            --j; break;
+        }
+      }
+    }
+    reverse(path->begin(), path->end());
+    return cmat[hyp.size()][ref.size()];
+  }
+
+  void BuildWordMatches(const vector<WordID>& hyp, NgramToIntsMap* nmap) const {
+    nmap->clear();
+    set<WordID> exists_both;
+    for (int i = 0; i < hyp.size(); ++i)
+      if (rwexists_.find(hyp[i]) != rwexists_.end())
+        exists_both.insert(hyp[i]);
+    for (int start=0; start<ref_.size(); ++start) {
+      if (exists_both.find(ref_[start]) == exists_both.end()) continue;
+      vector<WordID> cp;
+      int mlen = min(MAX_SHIFT_SIZE, static_cast<int>(ref_.size() - start));
+      for (int len=0; len<mlen; ++len) {
+        if (len && exists_both.find(ref_[start + len]) == exists_both.end()) break;
+        cp.push_back(ref_[start + len]);
+	(*nmap)[cp].insert(start);
+      }
+    }
+  }
+
+  static void PerformShift(const vector<WordID>& in,
+    int start, int end, int moveto, vector<WordID>* out) {
+    // cerr << "ps: " << start << " " << end << " " << moveto << endl;
+    out->clear();
+    if (moveto == -1) {
+      for (int i = start; i <= end; ++i)
+       out->push_back(in[i]);
+      for (int i = 0; i < start; ++i)
+       out->push_back(in[i]);
+      for (int i = end+1; i < in.size(); ++i)
+       out->push_back(in[i]);
+    } else if (moveto < start) {
+      for (int i = 0; i <= moveto; ++i)
+       out->push_back(in[i]);
+      for (int i = start; i <= end; ++i)
+       out->push_back(in[i]);
+      for (int i = moveto+1; i < start; ++i)
+       out->push_back(in[i]);
+      for (int i = end+1; i < in.size(); ++i)
+       out->push_back(in[i]);
+    } else if (moveto > end) {
+      for (int i = 0; i < start; ++i)
+       out->push_back(in[i]);
+      for (int i = end+1; i <= moveto; ++i)
+       out->push_back(in[i]);
+      for (int i = start; i <= end; ++i)
+       out->push_back(in[i]);
+      for (int i = moveto+1; i < in.size(); ++i)
+       out->push_back(in[i]);
+    } else {
+      for (int i = 0; i < start; ++i)
+       out->push_back(in[i]);
+      for (int i = end+1; (i < in.size()) && (i <= end + (moveto - start)); ++i)
+       out->push_back(in[i]);
+      for (int i = start; i <= end; ++i)
+       out->push_back(in[i]);
+      for (int i = (end + (moveto - start))+1; i < in.size(); ++i)
+       out->push_back(in[i]);
+    }
+    if (out->size() != in.size()) {
+      cerr << "ps: " << start << " " << end << " " << moveto << endl;
+      cerr << "in=" << TD::GetString(in) << endl;
+      cerr << "out=" << TD::GetString(*out) << endl;
+    }
+    assert(out->size() == in.size()); 
+    // cerr << "ps: " << TD::GetString(*out) << endl;
+  }
+
+  void GetAllPossibleShifts(const vector<WordID>& hyp,
+      const vector<int>& ralign,
+      const vector<bool>& herr,
+      const vector<bool>& rerr,
+      const int min_size,
+      vector<vector<Shift> >* shifts) const {
+    for (int start = 0; start < hyp.size(); ++start) {
+      vector<WordID> cp(1, hyp[start]);
+      NgramToIntsMap::iterator niter = nmap_.find(cp);
+      if (niter == nmap_.end()) continue;
+      bool ok = false;
+      int moveto;
+      for (set<int>::iterator i = niter->second.begin(); i != niter->second.end(); ++i) {
+        moveto = *i;
+        int rm = ralign[moveto];
+        ok = (start != rm &&
+              (rm - start) < MAX_SHIFT_DIST &&
+              (start - rm - 1) < MAX_SHIFT_DIST);
+        if (ok) break;
+      }
+      if (!ok) continue;
+      cp.clear();
+      for (int end = start + min_size - 1;
+           ok && end < hyp.size() && end < (start + MAX_SHIFT_SIZE); ++end) {
+        cp.push_back(hyp[end]);
+	vector<Shift>& sshifts = (*shifts)[end - start];
+        ok = false;
+        NgramToIntsMap::iterator niter = nmap_.find(cp);
+        if (niter == nmap_.end()) break;
+        bool any_herr = false;
+        for (int i = start; i <= end && !any_herr; ++i)
+          any_herr = herr[i];
+        if (!any_herr) {
+          ok = true;
+          continue;
+        }
+        for (set<int>::iterator mi = niter->second.begin();
+             mi != niter->second.end(); ++mi) {
+          int moveto = *mi;
+	  int rm = ralign[moveto];
+	  if (! ((rm != start) &&
+	        ((rm < start) || (rm > end)) &&
+		(rm - start <= MAX_SHIFT_DIST) &&
+		((start - rm - 1) <= MAX_SHIFT_DIST))) continue;
+          ok = true;
+	  bool any_rerr = false;
+	  for (int i = 0; (i <= end - start) && (!any_rerr); ++i)
+            any_rerr = rerr[moveto+i];
+	  if (!any_rerr) continue;
+	  for (int roff = 0; roff <= (end - start); ++roff) {
+	    int rmr = ralign[moveto+roff];
+	    if ((start != rmr) && ((roff == 0) || (rmr != ralign[moveto])))
+	      sshifts.push_back(Shift(start, end, moveto + roff));
+	  }
+        }
+      }
+    }
+  }
+
+  bool CalculateBestShift(const vector<WordID>& cur,
+                          const vector<WordID>& hyp,
+                          float curerr,
+                          const vector<TransType>& path,
+                          vector<WordID>* new_hyp,
+                          float* newerr,
+                          vector<TransType>* new_path) const {
+    vector<bool> herr, rerr;
+    vector<int> ralign;
+    int hpos = -1;
+    for (int i = 0; i < path.size(); ++i) {
+      switch (path[i]) {
+        case MATCH:
+	  ++hpos;
+	  herr.push_back(false);
+	  rerr.push_back(false);
+	  ralign.push_back(hpos);
+          break;
+        case SUBSTITUTION:
+	  ++hpos;
+	  herr.push_back(true);
+	  rerr.push_back(true);
+	  ralign.push_back(hpos);
+          break;
+        case INSERTION:
+	  ++hpos;
+	  herr.push_back(true);
+          break;
+	case DELETION:
+	  rerr.push_back(true);
+	  ralign.push_back(hpos);
+          break;
+      }
+    }
+#if 0
+    cerr << "RALIGN: ";
+    for (int i = 0; i < rerr.size(); ++i)
+      cerr << ralign[i] << " ";
+    cerr << endl;
+    cerr << "RERR: ";
+    for (int i = 0; i < rerr.size(); ++i)
+      cerr << (bool)rerr[i] << " ";
+    cerr << endl;
+    cerr << "HERR: ";
+    for (int i = 0; i < herr.size(); ++i)
+      cerr << (bool)herr[i] << " ";
+    cerr << endl;
+#endif
+
+    vector<vector<Shift> > shifts(MAX_SHIFT_SIZE + 1);
+    GetAllPossibleShifts(cur, ralign, herr, rerr, 1, &shifts);
+    float cur_best_shift_cost = 0;
+    *newerr = curerr;
+    vector<TransType> cur_best_path;
+    vector<WordID> cur_best_hyp;
+    
+    bool res = false;
+    for (int i = shifts.size() - 1; i >=0; --i) {
+      float curfix = curerr - (cur_best_shift_cost + *newerr);
+      float maxfix = 2.0f * (1 + i) - COSTS::shift;
+      if ((curfix > maxfix) || ((cur_best_shift_cost == 0) && (curfix == maxfix))) break;
+      for (int j = 0; j < shifts[i].size(); ++j) {
+        const Shift& s = shifts[i][j];
+	curfix = curerr - (cur_best_shift_cost + *newerr);
+	maxfix = 2.0f * (1 + i) - COSTS::shift;  // TODO remove?
+        if ((curfix > maxfix) || ((cur_best_shift_cost == 0) && (curfix == maxfix))) continue;
+	vector<WordID> shifted(cur.size());
+	PerformShift(cur, s.begin(), s.end(), ralign[s.moveto()], &shifted);
+	vector<TransType> try_path;
+	float try_cost = MinimumEditDistance(shifted, ref_, &try_path);
+	float gain = (*newerr + cur_best_shift_cost) - (try_cost + COSTS::shift);
+	if (gain > 0.0f || ((cur_best_shift_cost == 0.0f) && (gain == 0.0f))) {
+	  *newerr = try_cost;
+	  cur_best_shift_cost = COSTS::shift;
+	  new_path->swap(try_path);
+	  new_hyp->swap(shifted);
+	  res = true;
+	  // cerr << "Found better shift " << s.begin() << "..." << s.end() << " moveto " << s.moveto() << endl;
+	}
+      }
+    }
+
+    return res;
+  }
+
+  static void GetPathStats(const vector<TransType>& path, int* subs, int* ins, int* dels) {
+    *subs = *ins = *dels = 0;
+    for (int i = 0; i < path.size(); ++i) {
+      switch (path[i]) {
+        case SUBSTITUTION:
+	  ++(*subs);
+        case MATCH:
+          break;
+        case INSERTION:
+          ++(*ins); break;
+	case DELETION:
+          ++(*dels); break;
+      }
+    }
+  }
+
+  float CalculateAllShifts(const vector<WordID>& hyp,
+      int* subs, int* ins, int* dels, int* shifts) const {
+    BuildWordMatches(hyp, &nmap_);
+    vector<TransType> path;
+    float med_cost = MinimumEditDistance(hyp, ref_, &path);
+    float edits = 0;
+    vector<WordID> cur = hyp;
+    *shifts = 0;
+    if (ter_short_circuit_long_sentences < 0 ||
+        ref_.size() < ter_short_circuit_long_sentences) {
+      while (true) {
+        vector<WordID> new_hyp;
+        vector<TransType> new_path;
+        float new_med_cost;
+        if (!CalculateBestShift(cur, hyp, med_cost, path, &new_hyp, &new_med_cost, &new_path))
+          break;
+        edits += COSTS::shift;
+        ++(*shifts);
+        med_cost = new_med_cost;
+        path.swap(new_path);
+        cur.swap(new_hyp);
+      }
+    }
+    GetPathStats(path, subs, ins, dels);
+    return med_cost + edits;
+  }
+};
+
+class TERScore : public Score {
+  friend class TERScorer;
+
+ public:
+  static const unsigned kINSERTIONS = 0;
+  static const unsigned kDELETIONS = 1;
+  static const unsigned kSUBSTITUTIONS = 2;
+  static const unsigned kSHIFTS = 3;
+  static const unsigned kREF_WORDCOUNT = 4;
+  static const unsigned kDUMMY_LAST_ENTRY = 5;
+
+ TERScore() : stats(0,kDUMMY_LAST_ENTRY) {}
+  float ComputeScore() const {
+    float edits = static_cast<float>(stats[kINSERTIONS] + stats[kDELETIONS] + stats[kSUBSTITUTIONS] + stats[kSHIFTS]);
+    return edits / static_cast<float>(stats[kREF_WORDCOUNT]);
+  }
+  void ScoreDetails(string* details) const;
+  void PlusEquals(const Score& delta) {
+    stats += static_cast<const TERScore&>(delta).stats;
+  }
+  Score* GetZero() const {
+    return new TERScore;
+  }
+  void Subtract(const Score& rhs, Score* res) const {
+    static_cast<TERScore*>(res)->stats = stats - static_cast<const TERScore&>(rhs).stats;
+  }
+  void Encode(std::string* out) const {
+    ostringstream os;
+    os << stats[kINSERTIONS] << ' '
+       << stats[kDELETIONS] << ' '
+       << stats[kSUBSTITUTIONS] << ' '
+       << stats[kSHIFTS] << ' '
+       << stats[kREF_WORDCOUNT];
+    *out = os.str();
+  }
+  bool IsAdditiveIdentity() const {
+    for (int i = 0; i < kDUMMY_LAST_ENTRY; ++i)
+      if (stats[i] != 0) return false;
+    return true;
+  }
+ private:
+  valarray<int> stats;
+};
+
+Score* TERScorer::ScoreFromString(const std::string& data) {
+  istringstream is(data);
+  TERScore* r = new TERScore;
+  is >> r->stats[TERScore::kINSERTIONS]
+     >> r->stats[TERScore::kDELETIONS]
+     >> r->stats[TERScore::kSUBSTITUTIONS]
+     >> r->stats[TERScore::kSHIFTS]
+     >> r->stats[TERScore::kREF_WORDCOUNT];
+  return r;
+}
+
+void TERScore::ScoreDetails(std::string* details) const {
+  char buf[200];
+  sprintf(buf, "TER = %.2f, %3d|%3d|%3d|%3d (len=%d)",
+     ComputeScore() * 100.0f,  
+     stats[kINSERTIONS],
+     stats[kDELETIONS],
+     stats[kSUBSTITUTIONS],
+     stats[kSHIFTS],
+     stats[kREF_WORDCOUNT]);
+  *details = buf;
+}
+
+TERScorer::~TERScorer() {
+  for (vector<TERScorerImpl*>::iterator i = impl_.begin(); i != impl_.end(); ++i)
+    delete *i;
+}
+
+TERScorer::TERScorer(const vector<vector<WordID> >& refs) : impl_(refs.size()) {
+  for (int i = 0; i < refs.size(); ++i)
+    impl_[i] = new TERScorerImpl(refs[i]);
+}
+
+Score* TERScorer::ScoreCandidate(const std::vector<WordID>& hyp) const {
+  float best_score = numeric_limits<float>::max();
+  TERScore* res = new TERScore;
+  int avg_len = 0;
+  for (int i = 0; i < impl_.size(); ++i)
+    avg_len += impl_[i]->GetRefLength();
+  avg_len /= impl_.size();
+  for (int i = 0; i < impl_.size(); ++i) {
+    int subs, ins, dels, shifts;
+    float score = impl_[i]->Calculate(hyp, &subs, &ins, &dels, &shifts);
+    // cerr << "Component TER cost: " << score << endl;
+    if (score < best_score) {
+      res->stats[TERScore::kINSERTIONS] = ins;
+      res->stats[TERScore::kDELETIONS] = dels;
+      res->stats[TERScore::kSUBSTITUTIONS] = subs;
+      res->stats[TERScore::kSHIFTS] = shifts;
+      if (ter_use_average_ref_len) {
+        res->stats[TERScore::kREF_WORDCOUNT] = avg_len;
+      } else {
+        res->stats[TERScore::kREF_WORDCOUNT] = impl_[i]->GetRefLength();
+      }
+
+      best_score = score;
+    }
+  }
+  return res;
+}