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// $Id$
/***********************************************************************
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 "util/exception.hh"
using namespace std;
namespace Moses
{
LanguageModel::LanguageModel(const std::string &line) :
StatefulFeatureFunction(line, /* registerNow = */ false),
m_enableOOVFeature(false)
{
// load m_enableOOVFeature via SetParameter() first
// ReadParameters();
this->m_numScoreComponents = this->m_numTuneableComponents = m_enableOOVFeature ? 2 : 1;
// register with the correct m_numScoreComponents
// Register();
}
LanguageModel::~LanguageModel() {}
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::
EvaluateInIsolation(Phrase const& source, TargetPhrase const& targetPhrase,
ScoreComponentCollection &scoreBreakdown,
ScoreComponentCollection &estimatedScores) const
{
// contains factors used by this LM
float fullScore, nGramScore;
size_t oovCount;
CalcScore(targetPhrase, fullScore, nGramScore, oovCount);
float estimateScore = fullScore - nGramScore;
if (m_enableOOVFeature) {
vector<float> scores(2), estimateScores(2);
scores[0] = nGramScore;
scores[1] = oovCount;
scoreBreakdown.Assign(this, scores);
estimateScores[0] = estimateScore;
estimateScores[1] = 0;
estimatedScores.Assign(this, estimateScores);
} else {
scoreBreakdown.Assign(this, nGramScore);
estimatedScores.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.");
}
void LanguageModel::SetParameter(const std::string& key, const std::string& value)
{
if(key == "oov-feature") {
m_enableOOVFeature = Scan<bool>(value);
this->m_numScoreComponents = this->m_numTuneableComponents = m_enableOOVFeature ? 2 : 1;
} else {
StatefulFeatureFunction::SetParameter(key, value);
}
}
} // namespace Moses
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