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// $Id$
/***********************************************************************
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
***********************************************************************/
#include "PartialTranslOptColl.h"
#include <algorithm>
namespace Moses
{
/** constructor, intializes counters and thresholds */
PartialTranslOptColl::PartialTranslOptColl()
{
m_bestScore = -std::numeric_limits<float>::infinity();
m_worstScore = -std::numeric_limits<float>::infinity();
m_maxSize = StaticData::Instance().GetMaxNoPartTransOpt();
m_totalPruned = 0;
}
/** add a partial translation option to the collection (without pruning) */
void PartialTranslOptColl::AddNoPrune(const TranslationSystem* system, TranslationOption *partialTranslOpt)
{
partialTranslOpt->CalcScore(system);
if (partialTranslOpt->GetFutureScore() >= m_worstScore) {
m_list.push_back(partialTranslOpt);
if (partialTranslOpt->GetFutureScore() > m_bestScore)
m_bestScore = partialTranslOpt->GetFutureScore();
} else {
m_totalPruned++;
delete partialTranslOpt;
}
}
/** add a partial translation option to the collection, prune if necessary.
* This is done similar to the Prune() in TranslationOptionCollection */
void PartialTranslOptColl::Add(const TranslationSystem* system, TranslationOption *partialTranslOpt)
{
// add
AddNoPrune(system,partialTranslOpt );
// done if not too large (lazy pruning, only if twice as large as max)
if ( m_list.size() > 2 * m_maxSize ) {
Prune();
}
}
/** helper, used by pruning */
bool ComparePartialTranslationOption(const TranslationOption *a, const TranslationOption *b)
{
return a->GetFutureScore() > b->GetFutureScore();
}
/** pruning, remove partial translation options, if list too big */
void PartialTranslOptColl::Prune()
{
// done if not too big
if ( m_list.size() <= m_maxSize ) {
return;
}
// TRACE_ERR( "pruning partial translation options from size " << m_list.size() << std::endl);
// find nth element
nth_element(m_list.begin(),
m_list.begin() + m_maxSize,
m_list.end(),
ComparePartialTranslationOption);
m_worstScore = m_list[ m_maxSize-1 ]->GetFutureScore();
// delete the rest
for (size_t i = m_maxSize ; i < m_list.size() ; ++i) {
delete m_list[i];
m_totalPruned++;
}
m_list.resize(m_maxSize);
// TRACE_ERR( "pruned to size " << m_list.size() << ", total pruned: " << m_totalPruned << std::endl);
}
}
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