From 671c21451542e2dd20e45b4033d44d8e8735f87b Mon Sep 17 00:00:00 2001 From: Chris Dyer Date: Thu, 3 Dec 2009 16:33:55 -0500 Subject: initial check in --- vest/scorer.cc | 485 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 485 insertions(+) create mode 100644 vest/scorer.cc (limited to 'vest/scorer.cc') diff --git a/vest/scorer.cc b/vest/scorer.cc new file mode 100644 index 00000000..e242bb46 --- /dev/null +++ b/vest/scorer.cc @@ -0,0 +1,485 @@ +#include "scorer.h" + +#include +#include +#include +#include +#include +#include + +#include + +#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(correct) / static_cast(total); + } + void ScoreDetails(string* details) const { + ostringstream os; + os << "SER= " << ComputeScore() << " (" << correct << '/' << total << ')'; + *details = os.str(); + } + void PlusEquals(const Score& delta) { + correct += static_cast(delta).correct; + total += static_cast(delta).total; + } + Score* GetZero() const { return new SERScore; } + void Subtract(const Score& rhs, Score* res) const { + SERScore* r = static_cast(res); + r->correct = correct - static_cast(rhs).correct; + r->total = total - static_cast(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 >& references) : refs_(references) {} + Score* ScoreCandidate(const std::vector& 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 > 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* precs, float* bp) const; + valarray correct_ngram_hit_counts; + valarray hyp_ngram_counts; + float ref_len; + int hyp_len; +}; + +class BLEUScorerBase : public SentenceScorer { + public: + BLEUScorerBase(const std::vector >& references, + int n + ); + Score* ScoreCandidate(const std::vector& hyp) const; + static Score* ScoreFromString(const std::string& in); + + protected: + virtual float ComputeRefLength(const vector& hyp) const = 0; + private: + struct NGramCompare { + int operator() (const vector& a, const vector& 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, pair, NGramCompare> NGramCountMap; + void CountRef(const vector& ref) { + NGramCountMap tc; + vector ngram(n_); + int s = ref.size(); + for (int j=0; j& p = ngrams_[i->first]; + if (p.first < i->second.first) + p = i->second; + } + } + + void ComputeNgramStats(const vector& sent, + valarray* correct, + valarray* hyp) const { + assert(correct->size() == n_); + assert(hyp->size() == n_); + vector ngram(n_); + (*correct) *= 0; + (*hyp) *= 0; + int s = sent.size(); + for (int j=0; j& 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 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 >& 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& hyp) const { + if (lengths_.size() == 1) return lengths_[0]; + int bestd = 2000000; + int hl = hyp.size(); + int bl = -1; + for (vector::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 lengths_; +}; + +class NIST_BLEUScorer : public BLEUScorerBase { + public: + NIST_BLEUScorer(const std::vector >& 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& hyp) const { + return shortest_; + } + private: + float shortest_; +}; + +class Koehn_BLEUScorer : public BLEUScorerBase { + public: + Koehn_BLEUScorer(const std::vector >& 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& hyp) const { + return avg_; + } + private: + float avg_; +}; + +SentenceScorer* SentenceScorer::CreateSentenceScorer(const ScoreType type, + const std::vector >& 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 prev_trans; + const vector >& 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 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 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* 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(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(rhs); + BLEUScore* o = static_cast(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(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 >& references, + int n) : n_(n) { + for (vector >::const_iterator ci = references.begin(); + ci != references.end(); ++ci) { + lengths_.push_back(ci->size()); + CountRef(*ci); + } +} + +Score* BLEUScorerBase::ScoreCandidate(const vector& 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& ref_files) { + // TODO stop using valarray, start using ReadFile + cerr << "Loading references (" << ref_files.size() << " files)\n"; + valarray 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 > 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"; +} + -- cgit v1.2.3