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1 files changed, 518 insertions, 0 deletions
diff --git a/vest/ter.cc b/vest/ter.cc
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+++ 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;
+}
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