mosesdecoder/moses/LM/Base.cpp

123 lines
3.7 KiB
C++

// $Id$
/***********************************************************************
Moses - statistical machine translation system
Copyright (C) 2006-2011 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
***********************************************************************/
#include "Base.h"
#include "moses/TypeDef.h"
#include "moses/Util.h"
#include "moses/Manager.h"
#include "moses/ChartManager.h"
#include "moses/FactorCollection.h"
#include "moses/Phrase.h"
#include "moses/StaticData.h"
#include "util/exception.hh"
using namespace std;
namespace Moses
{
LanguageModel::LanguageModel(const std::string &line) :
StatefulFeatureFunction(StaticData::Instance().GetLMEnableOOVFeature() ? 2 : 1, line )
{
m_enableOOVFeature = StaticData::Instance().GetLMEnableOOVFeature();
}
LanguageModel::~LanguageModel() {}
float LanguageModel::GetWeight() const
{
//return StaticData::Instance().GetAllWeights().GetScoresForProducer(this)[0];
return StaticData::Instance().GetWeights(this)[0];
}
float LanguageModel::GetOOVWeight() const
{
if (m_enableOOVFeature) {
//return StaticData::Instance().GetAllWeights().GetScoresForProducer(this)[1];
return StaticData::Instance().GetWeights(this)[1];
} else {
return 0;
}
}
void LanguageModel::IncrementalCallback(Incremental::Manager &manager) const
{
UTIL_THROW(util::Exception, "Incremental search is only supported by KenLM.");
}
void LanguageModel::ReportHistoryOrder(std::ostream &out,const Phrase &phrase) const
{
// out << "ReportHistoryOrder not implemented";
}
void LanguageModel::Evaluate(const Phrase &source
, const TargetPhrase &targetPhrase
, ScoreComponentCollection &scoreBreakdown
, ScoreComponentCollection &estimatedFutureScore) const
{
// contains factors used by this LM
float fullScore, nGramScore;
size_t oovCount;
CalcScore(targetPhrase, fullScore, nGramScore, oovCount);
float estimateScore = fullScore - nGramScore;
if (StaticData::Instance().GetLMEnableOOVFeature()) {
vector<float> scores(2), estimateScores(2);
scores[0] = nGramScore;
scores[1] = oovCount;
scoreBreakdown.Assign(this, scores);
estimateScores[0] = estimateScore;
estimateScores[1] = 0;
estimatedFutureScore.Assign(this, estimateScores);
} else {
scoreBreakdown.Assign(this, nGramScore);
estimatedFutureScore.Assign(this, estimateScore);
}
}
const LanguageModel &LanguageModel::GetFirstLM()
{
static const LanguageModel *lmStatic = NULL;
if (lmStatic) {
return *lmStatic;
}
// 1st time looking up lm
const std::vector<const StatefulFeatureFunction*> &statefulFFs = StatefulFeatureFunction::GetStatefulFeatureFunctions();
for (size_t i = 0; i < statefulFFs.size(); ++i) {
const StatefulFeatureFunction *ff = statefulFFs[i];
const LanguageModel *lm = dynamic_cast<const LanguageModel*>(ff);
if (lm) {
lmStatic = lm;
return *lmStatic;
}
}
throw std::logic_error("Incremental search only supports one language model.");
}
} // namespace Moses