feature.cpp

解码器是基于短语的统计机器翻译系统的核心模块

/*
* Feature.cpp - store feature functions
*
* Copyright (C) 2006 by Zhongjun He <[e-mail]> 
Multilingual Interaction Technology and Evaluation Laboratory, ICT, CAS

* Begin       : 04/17/2006
* Last Change : 04/17/2006
*
* This program 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 program 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 General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

#include "Feature.h"
/************************************************************************/
/* consturtion function                                                 */
/************************************************************************/
Feature::Feature()
{
	p= 0.0;
	featfunc.clear();
	sigfunc = 0.0;
}	

Feature::Feature(int featnum)
{

	p= 0.0;
	int i=0;
	featfunc.resize(featnum);
	fill(featfunc.begin(),featfunc.end(),0.0);
	sigfunc = 0.0;

}

/************************************************************************/
/* clear                                                                */
/************************************************************************/
void Feature::clear()
{
	p= 0.0;
	featfunc.clear();
	sigfunc = 0.0;

}

/************************************************************************/
/* compute the feature function, Sigma lamda[i] * featfunc[i]           */
/************************************************************************/
void Feature::ComputeProb(const vector<double> &lamda)
{
	sigfunc = 0.0;
	for(int i=0 ; i<featfunc.size() ; i++)
	{
		sigfunc += lamda[i] * featfunc[i];
	}
	p = sigfunc;

}

/************************************************************************/
/* overload =                                                           */
/************************************************************************/
Feature& Feature::operator =(const Feature &right)
{
	int i=0;
    clear();

    featfunc = right.featfunc;
	p = right.p;
	sigfunc = right.sigfunc;
	return *this;
}

/************************************************************************/
/* overload <                                                           */
/************************************************************************/
bool Feature::operator <(const Feature &right)const
{
	return (p < right.p);
}

/************************************************************************/
/* overload >                                                           */
/************************************************************************/
bool Feature::operator >(const Feature &right)const
{
	return (p > right.p);
}

/************************************************************************/
/* overload ==                                                           */
/************************************************************************/
bool Feature::operator ==(const Feature &right)const
{
	return (p == right.p);
}

/************************************************************************/
/* overload +                                                           */
/************************************************************************/
Feature Feature::operator +(const Feature &right)
{
	Feature feat(right.featfunc.size());
	for (int i=0; i<featfunc.size(); i++)
	{
		feat.featfunc[i] = featfunc[i] + right.featfunc[i]; 
	}
	feat.p = p + right.sigfunc;             
	feat.sigfunc = sigfunc + right.sigfunc; 
	 
	return feat;
}

/************************************************************************/
/* print feature                                                        */
/************************************************************************/
void Feature::Show(ostream &out, bool isdetail)
{
	for(int i=0; i<featfunc.size() ; i++)
	{	out << featfunc[i] << " ";
	};

	if (isdetail)
	   out<<" # total probability:"<<p<<" , sigma function:  "<<sigfunc;
}