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+#ifndef _DTRAIN_KBESTGET_H_
+#define _DTRAIN_KBESTGET_H_
+
+#include "kbest.h" // cdec
+#include "verbose.h"
+#include "viterbi.h"
+#include "ff_register.h"
+#include "decoder.h"
+#include "weights.h"
+#include "logval.h"
+
+using namespace std;
+
+namespace dtrain
+{
+
+
+typedef double score_t;
+
+struct ScoredHyp
+{
+ vector<WordID> w;
+ SparseVector<double> f;
+ score_t model;
+ score_t score;
+ unsigned rank;
+};
+
+struct LocalScorer
+{
+ unsigned N_;
+ vector<score_t> w_;
+
+ virtual score_t
+ Score(vector<WordID>& hyp, vector<WordID>& ref, const unsigned rank)=0;
+
+ void Reset() {} // only for approx bleu
+
+ inline void
+ Init(unsigned N, vector<score_t> weights)
+ {
+ assert(N > 0);
+ N_ = N;
+ if (weights.empty()) for (unsigned i = 0; i < N_; i++) w_.push_back(1./N_);
+ else w_ = weights;
+ }
+
+ inline score_t
+ brevity_penaly(const unsigned hyp_len, const unsigned ref_len)
+ {
+ if (hyp_len > ref_len) return 1;
+ return exp(1 - (score_t)ref_len/hyp_len);
+ }
+};
+
+struct HypSampler : public DecoderObserver
+{
+ LocalScorer* scorer_;
+ vector<WordID>* ref_;
+ virtual vector<ScoredHyp>* GetSamples()=0;
+ inline void SetScorer(LocalScorer* scorer) { scorer_ = scorer; }
+ inline void SetRef(vector<WordID>& ref) { ref_ = &ref; }
+};
+///////////////////////////////////////////////////////////////////////////////
+
+
+
+
+struct KBestGetter : public HypSampler
+{
+ const unsigned k_;
+ const string filter_type_;
+ vector<ScoredHyp> s_;
+
+ KBestGetter(const unsigned k, const string filter_type) :
+ k_(k), filter_type_(filter_type) {}
+
+ virtual void
+ NotifyTranslationForest(const SentenceMetadata& smeta, Hypergraph* hg)
+ {
+ KBest(*hg);
+ }
+
+ vector<ScoredHyp>* GetSamples() { return &s_; }
+
+ void
+ KBest(const Hypergraph& forest)
+ {
+ if (filter_type_ == "unique") {
+ KBestUnique(forest);
+ } else if (filter_type_ == "no") {
+ KBestNoFilter(forest);
+ }
+ }
+
+ void
+ KBestUnique(const Hypergraph& forest)
+ {
+ s_.clear();
+ KBest::KBestDerivations<vector<WordID>, ESentenceTraversal,
+ KBest::FilterUnique, prob_t, EdgeProb> kbest(forest, k_);
+ for (unsigned i = 0; i < k_; ++i) {
+ const KBest::KBestDerivations<vector<WordID>, ESentenceTraversal, KBest::FilterUnique,
+ prob_t, EdgeProb>::Derivation* d =
+ kbest.LazyKthBest(forest.nodes_.size() - 1, i);
+ if (!d) break;
+ ScoredHyp h;
+ h.w = d->yield;
+ h.f = d->feature_values;
+ h.model = log(d->score);
+ h.rank = i;
+ h.score = scorer_->Score(h.w, *ref_, i);
+ s_.push_back(h);
+ }
+ }
+
+ void
+ KBestNoFilter(const Hypergraph& forest)
+ {
+ s_.clear();
+ KBest::KBestDerivations<vector<WordID>, ESentenceTraversal> kbest(forest, k_);
+ for (unsigned i = 0; i < k_; ++i) {
+ const KBest::KBestDerivations<vector<WordID>, ESentenceTraversal>::Derivation* d =
+ kbest.LazyKthBest(forest.nodes_.size() - 1, i);
+ if (!d) break;
+ ScoredHyp h;
+ h.w = d->yield;
+ h.f = d->feature_values;
+ h.model = log(d->score);
+ h.rank = i;
+ h.score = scorer_->Score(h.w, *ref_, i);
+ s_.push_back(h);
+ }
+ }
+};
+
+
+} // namespace
+
+#endif
+