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#pragma once
#include <fstream>
#include <string>
#include <vector>
#include <boost/shared_ptr.hpp>
#include "Ngram.h"
#include "Reference.h"
#include "ScopedVector.h"
#include "ScoreData.h"
#include "StatisticsBasedScorer.h"
#include "Types.h"
namespace MosesTuning
{
const size_t kBleuNgramOrder = 4;
/**
* Bleu scoring
*/
class BleuScorer: public StatisticsBasedScorer
{
public:
enum ReferenceLengthType {
AVERAGE,
CLOSEST,
SHORTEST
};
explicit BleuScorer(const std::string& config = "");
~BleuScorer();
static std::vector<float> ScoreNbestList(const std::string& scoreFile, const std::string& featureFile);
virtual void setReferenceFiles(const std::vector<std::string>& referenceFiles);
virtual void prepareStats(std::size_t sid, const std::string& text, ScoreStats& entry);
virtual statscore_t calculateScore(const std::vector<ScoreStatsType>& comps) const;
virtual std::size_t NumberOfScores() const {
return 2 * kBleuNgramOrder + 1;
}
void CalcBleuStats(const Reference& ref, const std::string& text, ScoreStats& entry) const;
int CalcReferenceLength(const Reference& ref, std::size_t length) const;
ReferenceLengthType GetReferenceLengthType() const {
return m_ref_length_type;
}
void SetReferenceLengthType(ReferenceLengthType type) {
m_ref_length_type = type;
}
const std::vector<Reference*>& GetReferences() const {
return m_references.get();
}
virtual float getReferenceLength(const std::vector<ScoreStatsType>& totals) const {
return totals[kBleuNgramOrder*2];
}
/**
* Count the ngrams of each type, up to the given length in the input line.
*/
size_t CountNgrams(const std::string& line, NgramCounts& counts, unsigned int n, bool is_testing=false) const;
void DumpCounts(std::ostream* os, const NgramCounts& counts) const;
// NOTE: this function is used for unit testing.
bool OpenReferenceStream(std::istream* is, std::size_t file_id);
void ProcessReferenceLine(const std::string& line, Reference* ref) const;
bool GetNextReferenceFromStreams(std::vector<boost::shared_ptr<std::ifstream> >& referenceStreams, Reference& ref) const;
//private:
protected:
ReferenceLengthType m_ref_length_type;
// reference translations.
ScopedVector<Reference> m_references;
// constructor used by subclasses
BleuScorer(const std::string& name, const std::string& config): StatisticsBasedScorer(name,config) {}
// no copying allowed
BleuScorer(const BleuScorer&);
BleuScorer& operator=(const BleuScorer&);
};
/** Computes sentence-level BLEU+1 score.
* This function is used in PRO.
*/
float smoothedSentenceBleu
(const std::vector<float>& stats, float smoothing=1.0, bool smoothBP=false);
/** Computes sentence-level BLEU score given a background corpus.
* This function is used in batch MIRA.
*/
float sentenceLevelBackgroundBleu(const std::vector<float>& sent, const std::vector<float>& bg);
}
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