languagemodelmultifactor.cpp.svn-base

moses开源的机器翻译系统

// $Id$

/***********************************************************************
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 "LanguageModelMultiFactor.h"
#include "Phrase.h"

LanguageModelMultiFactor::LanguageModelMultiFactor(bool registerScore, ScoreIndexManager &scoreIndexManager)
:LanguageModel(registerScore, scoreIndexManager)
{}

std::string LanguageModelMultiFactor::GetScoreProducerDescription() const
{
	std::ostringstream oss;
	// what about LMs that are over multiple factors at once, POS + stem, for example?
	oss << GetNGramOrder() << "-gram LM score, factor-type= ??? " << ", file=" << m_filePath;
	return oss.str();
} 

bool LanguageModelMultiFactor::Useable(const Phrase &phrase) const
{
	if (phrase.GetSize()==0)
		return false;
	
	// whether phrase contains all factors in this LM
	const Word &word = phrase.GetWord(0);
	for (size_t currFactor = 0 ; currFactor < MAX_NUM_FACTORS ; ++currFactor)
	{
		if (m_factorTypes[currFactor] && word[currFactor] == NULL)
			return false;
	}
	return  true;

}