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// -*- c++ -*-
// $Id$
/***********************************************************************
Moses - factored phrase-based language decoder
Copyright (C) 2006 University of Edinburgh
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
***********************************************************************/
#ifndef moses_TranslationOption_h
#define moses_TranslationOption_h
#include <map>
#include <vector>
#include <boost/functional/hash.hpp>
#include "Bitmap.h"
#include "Range.h"
#include "Phrase.h"
#include "TargetPhrase.h"
#include "Hypothesis.h"
#include "Util.h"
#include "TypeDef.h"
#include "ScoreComponentCollection.h"
#include "StaticData.h"
namespace Moses
{
class PhraseDictionary;
class GenerationDictionary;
class FeatureFunction;
class LexicalReordering;
/** Available phrase translation for a particular sentence pair.
* In a multi-factor model, this is expanded from the entries in the
* translation tables and generation tables (and pruned to the maximum
* number allowed). By pre-computing the allowable phrase translations,
* efficient beam search in Manager is possible when expanding instances
* of the class Hypothesis - the states in the search.
*
* A translation option contains source and target phrase, aggregate
* and details scores (in m_scoreBreakdown), including an estimate
* how expensive this option will be in search (used to build the
* future cost matrix.)
*
* m_targetPhrase points to a phrase-table entry.
* The source word range is zero-indexed, so it can't refer to an empty range. The target phrase may be empty.
*/
class TranslationOption
{
friend std::ostream& operator<<(std::ostream& out, const TranslationOption& possibleTranslation);
protected:
TargetPhrase m_targetPhrase; /*< output phrase when using this translation option */
const InputPath *m_inputPath;
const Range m_sourceWordsRange; /*< word position in the input that are covered by this translation option */
float m_futureScore; /*< estimate of total cost when using this translation option, includes language model probabilities */
// typedef std::map<const LexicalReordering*, Scores> _ScoreCacheMap;
// _ScoreCacheMap m_lexReorderingScores;
// m_lexReorderingScores was moved to TargetPhrase.h so that phrase tables
// can add information (such as lexical reordering scores) to target phrases
// during lookup.
public:
struct Better {
bool operator()(TranslationOption const& a, TranslationOption const& b) const {
return a.GetFutureScore() > b.GetFutureScore();
}
bool operator()(TranslationOption const* a, TranslationOption const* b) const {
return a->GetFutureScore() > b->GetFutureScore();
}
};
explicit TranslationOption(); // For initial hypo that does translate nothing
/** constructor. Used by initial translation step */
TranslationOption(const Range &range
, const TargetPhrase &targetPhrase);
/** returns true if all feature types in featuresToCheck are compatible between the two phrases */
bool IsCompatible(const Phrase& phrase, const std::vector<FactorType>& featuresToCheck) const;
/** returns target phrase */
inline const TargetPhrase &GetTargetPhrase() const {
return m_targetPhrase;
}
/** returns source word range */
inline const Range &GetSourceWordsRange() const {
return m_sourceWordsRange;
}
/** returns source phrase */
const InputPath &GetInputPath() const;
void SetInputPath(const InputPath &inputPath);
/** whether source span overlaps with those of a hypothesis */
bool Overlap(const Hypothesis &hypothesis) const;
/** return start index of source phrase */
inline size_t GetStartPos() const {
return m_sourceWordsRange.GetStartPos();
}
/** return end index of source phrase */
inline size_t GetEndPos() const {
return m_sourceWordsRange.GetEndPos();
}
/** return length of source phrase */
inline size_t GetSize() const {
return m_sourceWordsRange.GetEndPos() - m_sourceWordsRange.GetStartPos() + 1;
}
/** return estimate of total cost of this option */
inline float GetFutureScore() const {
return m_futureScore;
}
/** return true if the source phrase translates into nothing */
inline bool IsDeletionOption() const {
return m_targetPhrase.GetSize() == 0;
}
/** returns detailed component scores */
inline const ScoreComponentCollection &GetScoreBreakdown() const {
return m_targetPhrase.GetScoreBreakdown();
}
inline ScoreComponentCollection &GetScoreBreakdown() {
return m_targetPhrase.GetScoreBreakdown();
}
void EvaluateWithSourceContext(const InputType &input);
void UpdateScore(ScoreComponentCollection *futureScoreBreakdown = NULL) {
m_targetPhrase.UpdateScore(futureScoreBreakdown);
}
/** returns cached scores */
// inline
const Scores*
GetLexReorderingScores(const LexicalReordering *scoreProducer) const;
// {
// return m_targetPhrase.GetExtraScores(scoreProducer);
// }
void CacheLexReorderingScores(const LexicalReordering &scoreProducer,
const Scores &score);
TO_STRING();
bool operator== (const TranslationOption &rhs) const {
return m_sourceWordsRange == rhs.m_sourceWordsRange &&
m_targetPhrase == rhs.m_targetPhrase;
}
};
//XXX: This doesn't look at the alignment. Is this correct?
inline size_t hash_value(const TranslationOption& translationOption)
{
size_t seed = 0;
boost::hash_combine(seed, translationOption.GetTargetPhrase());
boost::hash_combine(seed, translationOption.GetStartPos());
boost::hash_combine(seed, translationOption.GetEndPos());
return seed;
}
}
#endif
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