languagemodelsri.h.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
***********************************************************************/

#pragma once

#include <string>
#include <vector>
#include "Factor.h"
#include "TypeDef.h"
#include "Vocab.h"
#include "LanguageModelSingleFactor.h"

class Factor;
class Phrase;
class Ngram; // SRI forward decl

class LanguageModelSRI : public LanguageModelSingleFactor
{
protected:
	std::vector<VocabIndex> m_lmIdLookup;
	Vocab 			*m_srilmVocab;
	Ngram 			*m_srilmModel;
	VocabIndex	m_unknownId;

	float GetValue(VocabIndex wordId, VocabIndex *context) const;
	void CreateFactors();
	VocabIndex GetLmID( const std::string &str ) const;
	VocabIndex GetLmID( const Factor *factor ) const;
	
public:
	LanguageModelSRI(bool registerScore, ScoreIndexManager &scoreIndexManager);
	~LanguageModelSRI();
	bool Load(const std::string &filePath
					, FactorType factorType
					, float weight
					, size_t nGramOrder);

  virtual float GetValue(const std::vector<const Word*> &contextFactor, State* finalState = 0, unsigned int* len = 0) const;
};