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-rw-r--r--vest/scorer.cc485
1 files changed, 485 insertions, 0 deletions
diff --git a/vest/scorer.cc b/vest/scorer.cc
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+++ b/vest/scorer.cc
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+#include "scorer.h"
+
+#include <map>
+#include <sstream>
+#include <iostream>
+#include <fstream>
+#include <cstdio>
+#include <valarray>
+
+#include <boost/shared_ptr.hpp>
+
+#include "viterbi_envelope.h"
+#include "error_surface.h"
+#include "ter.h"
+#include "comb_scorer.h"
+#include "tdict.h"
+#include "stringlib.h"
+
+using boost::shared_ptr;
+using namespace std;
+
+const bool minimize_segments = true; // if adjacent segments have equal scores, merge them
+
+ScoreType ScoreTypeFromString(const std::string& st) {
+ const string sl = LowercaseString(st);
+ if (sl == "ser")
+ return SER;
+ if (sl == "ter")
+ return TER;
+ if (sl == "bleu" || sl == "ibm_bleu")
+ return IBM_BLEU;
+ if (sl == "nist_bleu")
+ return NIST_BLEU;
+ if (sl == "koehn_bleu")
+ return Koehn_BLEU;
+ if (sl == "combi")
+ return BLEU_minus_TER_over_2;
+ cerr << "Don't understand score type '" << sl << "', defaulting to ibm_bleu.\n";
+ return IBM_BLEU;
+}
+
+Score::~Score() {}
+SentenceScorer::~SentenceScorer() {}
+
+class SERScore : public Score {
+ friend class SERScorer;
+ public:
+ SERScore() : correct(0), total(0) {}
+ float ComputeScore() const {
+ return static_cast<float>(correct) / static_cast<float>(total);
+ }
+ void ScoreDetails(string* details) const {
+ ostringstream os;
+ os << "SER= " << ComputeScore() << " (" << correct << '/' << total << ')';
+ *details = os.str();
+ }
+ void PlusEquals(const Score& delta) {
+ correct += static_cast<const SERScore&>(delta).correct;
+ total += static_cast<const SERScore&>(delta).total;
+ }
+ Score* GetZero() const { return new SERScore; }
+ void Subtract(const Score& rhs, Score* res) const {
+ SERScore* r = static_cast<SERScore*>(res);
+ r->correct = correct - static_cast<const SERScore&>(rhs).correct;
+ r->total = total - static_cast<const SERScore&>(rhs).total;
+ }
+ void Encode(std::string* out) const {
+ assert(!"not implemented");
+ }
+ bool IsAdditiveIdentity() const {
+ return (total == 0 && correct == 0); // correct is always 0 <= n <= total
+ }
+ private:
+ int correct, total;
+};
+
+class SERScorer : public SentenceScorer {
+ public:
+ SERScorer(const vector<vector<WordID> >& references) : refs_(references) {}
+ Score* ScoreCandidate(const std::vector<WordID>& hyp) const {
+ SERScore* res = new SERScore;
+ res->total = 1;
+ for (int i = 0; i < refs_.size(); ++i)
+ if (refs_[i] == hyp) res->correct = 1;
+ return res;
+ }
+ static Score* ScoreFromString(const std::string& data) {
+ assert(!"Not implemented");
+ }
+ private:
+ vector<vector<WordID> > refs_;
+};
+
+class BLEUScore : public Score {
+ friend class BLEUScorerBase;
+ public:
+ BLEUScore(int n) : correct_ngram_hit_counts(0,n), hyp_ngram_counts(0,n) {
+ ref_len = 0;
+ hyp_len = 0; }
+ float ComputeScore() const;
+ void ScoreDetails(string* details) const;
+ void PlusEquals(const Score& delta);
+ Score* GetZero() const;
+ void Subtract(const Score& rhs, Score* res) const;
+ void Encode(std::string* out) const;
+ bool IsAdditiveIdentity() const {
+ if (fabs(ref_len) > 0.1f || hyp_len != 0) return false;
+ for (int i = 0; i < correct_ngram_hit_counts.size(); ++i)
+ if (hyp_ngram_counts[i] != 0 ||
+ correct_ngram_hit_counts[i] != 0) return false;
+ return true;
+ }
+ private:
+ float ComputeScore(vector<float>* precs, float* bp) const;
+ valarray<int> correct_ngram_hit_counts;
+ valarray<int> hyp_ngram_counts;
+ float ref_len;
+ int hyp_len;
+};
+
+class BLEUScorerBase : public SentenceScorer {
+ public:
+ BLEUScorerBase(const std::vector<std::vector<WordID> >& references,
+ int n
+ );
+ Score* ScoreCandidate(const std::vector<WordID>& hyp) const;
+ static Score* ScoreFromString(const std::string& in);
+
+ protected:
+ virtual float ComputeRefLength(const vector<WordID>& hyp) const = 0;
+ private:
+ struct NGramCompare {
+ int operator() (const vector<WordID>& a, const vector<WordID>& b) {
+ size_t as = a.size();
+ size_t bs = b.size();
+ const size_t s = (as < bs ? as : bs);
+ for (size_t i = 0; i < s; ++i) {
+ int d = a[i] - b[i];
+ if (d < 0) return true;
+ if (d > 0) return false;
+ }
+ return as < bs;
+ }
+ };
+ typedef map<vector<WordID>, pair<int,int>, NGramCompare> NGramCountMap;
+ void CountRef(const vector<WordID>& ref) {
+ NGramCountMap tc;
+ vector<WordID> ngram(n_);
+ int s = ref.size();
+ for (int j=0; j<s; ++j) {
+ int remaining = s-j;
+ int k = (n_ < remaining ? n_ : remaining);
+ ngram.clear();
+ for (int i=1; i<=k; ++i) {
+ ngram.push_back(ref[j + i - 1]);
+ tc[ngram].first++;
+ }
+ }
+ for (NGramCountMap::iterator i = tc.begin(); i != tc.end(); ++i) {
+ pair<int,int>& p = ngrams_[i->first];
+ if (p.first < i->second.first)
+ p = i->second;
+ }
+ }
+
+ void ComputeNgramStats(const vector<WordID>& sent,
+ valarray<int>* correct,
+ valarray<int>* hyp) const {
+ assert(correct->size() == n_);
+ assert(hyp->size() == n_);
+ vector<WordID> ngram(n_);
+ (*correct) *= 0;
+ (*hyp) *= 0;
+ int s = sent.size();
+ for (int j=0; j<s; ++j) {
+ int remaining = s-j;
+ int k = (n_ < remaining ? n_ : remaining);
+ ngram.clear();
+ for (int i=1; i<=k; ++i) {
+ ngram.push_back(sent[j + i - 1]);
+ pair<int,int>& p = ngrams_[ngram];
+ if (p.second < p.first) {
+ ++p.second;
+ (*correct)[i-1]++;
+ }
+ // if the 1 gram isn't found, don't try to match don't need to match any 2- 3- .. grams:
+ if (!p.first) {
+ for (; i<=k; ++i)
+ (*hyp)[i-1]++;
+ } else {
+ (*hyp)[i-1]++;
+ }
+ }
+ }
+ }
+
+ mutable NGramCountMap ngrams_;
+ int n_;
+ vector<int> lengths_;
+};
+
+Score* BLEUScorerBase::ScoreFromString(const std::string& in) {
+ istringstream is(in);
+ int n;
+ is >> n;
+ BLEUScore* r = new BLEUScore(n);
+ is >> r->ref_len >> r->hyp_len;
+
+ for (int i = 0; i < n; ++i) {
+ is >> r->correct_ngram_hit_counts[i];
+ is >> r->hyp_ngram_counts[i];
+ }
+ return r;
+}
+
+class IBM_BLEUScorer : public BLEUScorerBase {
+ public:
+ IBM_BLEUScorer(const std::vector<std::vector<WordID> >& references,
+ int n=4) : BLEUScorerBase(references, n), lengths_(references.size()) {
+ for (int i=0; i < references.size(); ++i)
+ lengths_[i] = references[i].size();
+ }
+ protected:
+ float ComputeRefLength(const vector<WordID>& hyp) const {
+ if (lengths_.size() == 1) return lengths_[0];
+ int bestd = 2000000;
+ int hl = hyp.size();
+ int bl = -1;
+ for (vector<int>::const_iterator ci = lengths_.begin(); ci != lengths_.end(); ++ci) {
+ int cl = *ci;
+ if (abs(cl - hl) < bestd) {
+ bestd = abs(cl - hl);
+ bl = cl;
+ }
+ }
+ return bl;
+ }
+ private:
+ vector<int> lengths_;
+};
+
+class NIST_BLEUScorer : public BLEUScorerBase {
+ public:
+ NIST_BLEUScorer(const std::vector<std::vector<WordID> >& references,
+ int n=4) : BLEUScorerBase(references, n),
+ shortest_(references[0].size()) {
+ for (int i=1; i < references.size(); ++i)
+ if (references[i].size() < shortest_)
+ shortest_ = references[i].size();
+ }
+ protected:
+ float ComputeRefLength(const vector<WordID>& hyp) const {
+ return shortest_;
+ }
+ private:
+ float shortest_;
+};
+
+class Koehn_BLEUScorer : public BLEUScorerBase {
+ public:
+ Koehn_BLEUScorer(const std::vector<std::vector<WordID> >& references,
+ int n=4) : BLEUScorerBase(references, n),
+ avg_(0) {
+ for (int i=0; i < references.size(); ++i)
+ avg_ += references[i].size();
+ avg_ /= references.size();
+ }
+ protected:
+ float ComputeRefLength(const vector<WordID>& hyp) const {
+ return avg_;
+ }
+ private:
+ float avg_;
+};
+
+SentenceScorer* SentenceScorer::CreateSentenceScorer(const ScoreType type,
+ const std::vector<std::vector<WordID> >& refs) {
+ switch (type) {
+ case IBM_BLEU: return new IBM_BLEUScorer(refs, 4);
+ case NIST_BLEU: return new NIST_BLEUScorer(refs, 4);
+ case Koehn_BLEU: return new Koehn_BLEUScorer(refs, 4);
+ case TER: return new TERScorer(refs);
+ case SER: return new SERScorer(refs);
+ case BLEU_minus_TER_over_2: return new BLEUTERCombinationScorer(refs);
+ default:
+ assert(!"Not implemented!");
+ }
+}
+
+Score* SentenceScorer::CreateScoreFromString(const ScoreType type, const std::string& in) {
+ switch (type) {
+ case IBM_BLEU:
+ case NIST_BLEU:
+ case Koehn_BLEU:
+ return BLEUScorerBase::ScoreFromString(in);
+ case TER:
+ return TERScorer::ScoreFromString(in);
+ case SER:
+ return SERScorer::ScoreFromString(in);
+ case BLEU_minus_TER_over_2:
+ return BLEUTERCombinationScorer::ScoreFromString(in);
+ default:
+ assert(!"Not implemented!");
+ }
+}
+
+void SentenceScorer::ComputeErrorSurface(const ViterbiEnvelope& ve, ErrorSurface* env) const {
+ vector<WordID> prev_trans;
+ const vector<shared_ptr<Segment> >& ienv = ve.GetSortedSegs();
+ env->resize(ienv.size());
+ Score* prev_score = NULL;
+ int j = 0;
+ for (int i = 0; i < ienv.size(); ++i) {
+ const Segment& seg = *ienv[i];
+ vector<WordID> trans;
+ seg.ConstructTranslation(&trans);
+ // cerr << "Scoring: " << TD::GetString(trans) << endl;
+ if (trans == prev_trans) {
+ if (!minimize_segments) {
+ assert(prev_score); // if this fails, it means
+ // the decoder can generate null translations
+ ErrorSegment& out = (*env)[j];
+ out.delta = prev_score->GetZero();
+ out.x = seg.x;
+ ++j;
+ }
+ // cerr << "Identical translation, skipping scoring\n";
+ } else {
+ Score* score = ScoreCandidate(trans);
+ // cerr << "score= " << score->ComputeScore() << "\n";
+ Score* cur_delta = score->GetZero();
+ // just record the score diffs
+ if (!prev_score)
+ prev_score = score->GetZero();
+
+ score->Subtract(*prev_score, cur_delta);
+ delete prev_score;
+ prev_trans.swap(trans);
+ prev_score = score;
+ if ((!minimize_segments) || (!cur_delta->IsAdditiveIdentity())) {
+ ErrorSegment& out = (*env)[j];
+ out.delta = cur_delta;
+ out.x = seg.x;
+ ++j;
+ }
+ }
+ }
+ delete prev_score;
+ // cerr << " In segments: " << ienv.size() << endl;
+ // cerr << "Out segments: " << j << endl;
+ assert(j > 0);
+ env->resize(j);
+}
+
+void BLEUScore::ScoreDetails(std::string* details) const {
+ char buf[2000];
+ vector<float> precs(4);
+ float bp;
+ float bleu = ComputeScore(&precs, &bp);
+ sprintf(buf, "BLEU = %.2f, %.1f|%.1f|%.1f|%.1f (brev=%.3f)",
+ bleu*100.0,
+ precs[0]*100.0,
+ precs[1]*100.0,
+ precs[2]*100.0,
+ precs[3]*100.0,
+ bp);
+ *details = buf;
+}
+
+float BLEUScore::ComputeScore(vector<float>* precs, float* bp) const {
+ float log_bleu = 0;
+ if (precs) precs->clear();
+ int count = 0;
+ for (int i = 0; i < hyp_ngram_counts.size(); ++i) {
+ if (hyp_ngram_counts[i] > 0) {
+ float lprec = log(correct_ngram_hit_counts[i]) - log(hyp_ngram_counts[i]);
+ if (precs) precs->push_back(exp(lprec));
+ log_bleu += lprec;
+ ++count;
+ }
+ }
+ log_bleu /= static_cast<float>(count);
+ float lbp = 0.0;
+ if (hyp_len < ref_len)
+ lbp = (hyp_len - ref_len) / hyp_len;
+ log_bleu += lbp;
+ if (bp) *bp = exp(lbp);
+ return exp(log_bleu);
+}
+
+float BLEUScore::ComputeScore() const {
+ return ComputeScore(NULL, NULL);
+}
+
+void BLEUScore::Subtract(const Score& rhs, Score* res) const {
+ const BLEUScore& d = static_cast<const BLEUScore&>(rhs);
+ BLEUScore* o = static_cast<BLEUScore*>(res);
+ o->ref_len = ref_len - d.ref_len;
+ o->hyp_len = hyp_len - d.hyp_len;
+ o->correct_ngram_hit_counts = correct_ngram_hit_counts - d.correct_ngram_hit_counts;
+ o->hyp_ngram_counts = hyp_ngram_counts - d.hyp_ngram_counts;
+}
+
+void BLEUScore::PlusEquals(const Score& delta) {
+ const BLEUScore& d = static_cast<const BLEUScore&>(delta);
+ correct_ngram_hit_counts += d.correct_ngram_hit_counts;
+ hyp_ngram_counts += d.hyp_ngram_counts;
+ ref_len += d.ref_len;
+ hyp_len += d.hyp_len;
+}
+
+Score* BLEUScore::GetZero() const {
+ return new BLEUScore(hyp_ngram_counts.size());
+}
+
+void BLEUScore::Encode(std::string* out) const {
+ ostringstream os;
+ const int n = correct_ngram_hit_counts.size();
+ os << n << ' ' << ref_len << ' ' << hyp_len;
+ for (int i = 0; i < n; ++i)
+ os << ' ' << correct_ngram_hit_counts[i] << ' ' << hyp_ngram_counts[i];
+ *out = os.str();
+}
+
+BLEUScorerBase::BLEUScorerBase(const std::vector<std::vector<WordID> >& references,
+ int n) : n_(n) {
+ for (vector<vector<WordID> >::const_iterator ci = references.begin();
+ ci != references.end(); ++ci) {
+ lengths_.push_back(ci->size());
+ CountRef(*ci);
+ }
+}
+
+Score* BLEUScorerBase::ScoreCandidate(const vector<WordID>& hyp) const {
+ BLEUScore* bs = new BLEUScore(n_);
+ for (NGramCountMap::iterator i=ngrams_.begin(); i != ngrams_.end(); ++i)
+ i->second.second = 0;
+ ComputeNgramStats(hyp, &bs->correct_ngram_hit_counts, &bs->hyp_ngram_counts);
+ bs->ref_len = ComputeRefLength(hyp);
+ bs->hyp_len = hyp.size();
+ return bs;
+}
+
+DocScorer::~DocScorer() {
+ for (int i=0; i < scorers_.size(); ++i)
+ delete scorers_[i];
+}
+
+DocScorer::DocScorer(
+ const ScoreType type,
+ const std::vector<std::string>& ref_files) {
+ // TODO stop using valarray, start using ReadFile
+ cerr << "Loading references (" << ref_files.size() << " files)\n";
+ valarray<ifstream> ifs(ref_files.size());
+ for (int i=0; i < ref_files.size(); ++i) {
+ ifs[i].open(ref_files[i].c_str());
+ assert(ifs[i].good());
+ }
+ char buf[64000];
+ bool expect_eof = false;
+ while (!ifs[0].eof()) {
+ vector<vector<WordID> > refs(ref_files.size());
+ for (int i=0; i < ref_files.size(); ++i) {
+ if (ifs[i].eof()) break;
+ ifs[i].getline(buf, 64000);
+ refs[i].clear();
+ if (strlen(buf) == 0) {
+ if (ifs[i].eof()) {
+ if (!expect_eof) {
+ assert(i == 0);
+ expect_eof = true;
+ }
+ break;
+ }
+ } else {
+ TD::ConvertSentence(buf, &refs[i]);
+ assert(!refs[i].empty());
+ }
+ assert(!expect_eof);
+ }
+ if (!expect_eof) scorers_.push_back(SentenceScorer::CreateSentenceScorer(type, refs));
+ }
+ cerr << "Loaded reference translations for " << scorers_.size() << " sentences.\n";
+}
+
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-21 18:07:42 +0000