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// $Id: SquareMatrix.cpp 1964 2008-12-20 20:22:35Z phkoehn $
// vim:tabstop=2
/***********************************************************************
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 <string>
#include <iostream>
#include "SquareMatrix.h"
#include "TypeDef.h"
#include "Util.h"
using namespace std;
namespace Moses
{
/**
* Calculare future score estimate for a given coverage bitmap
*
* /param bitmap coverage bitmap
*/
float SquareMatrix::CalcFutureScore( WordsBitmap const &bitmap ) const
{
const size_t notInGap= numeric_limits<size_t>::max();
size_t startGap = notInGap;
float futureScore = 0.0f;
for(size_t currPos = 0 ; currPos < bitmap.GetSize() ; currPos++)
{
// start of a new gap?
if(bitmap.GetValue(currPos) == false && startGap == notInGap)
{
startGap = currPos;
}
// end of a gap?
else if(bitmap.GetValue(currPos) == true && startGap != notInGap)
{
futureScore += GetScore(startGap, currPos - 1);
startGap = notInGap;
}
}
// coverage ending with gap?
if (startGap != notInGap)
{
futureScore += GetScore(startGap, bitmap.GetSize() - 1);
}
return futureScore;
}
/**
* Calculare future score estimate for a given coverage bitmap
* and an additional span that is also covered. This function is used
* to compute future score estimates for hypotheses that we may want
* build, but first want to check.
*
* Note: this function is implemented a bit more complex than
* the basic one (w/o additional phrase) for speed reasons,
* which is probably overkill.
*
* /param bitmap coverage bitmap
* /param startPos start of the span that is added to the coverage
* /param endPos end of the span that is added to the coverage
*/
float SquareMatrix::CalcFutureScore( WordsBitmap const &bitmap, size_t startPos, size_t endPos ) const
{
const size_t notInGap= numeric_limits<size_t>::max();
float futureScore = 0.0f;
size_t startGap = bitmap.GetFirstGapPos();
if (startGap == NOT_FOUND) return futureScore; // everything filled
// start loop at first gap
size_t startLoop = startGap+1;
if (startPos == startGap) // unless covered by phrase
{
startGap = notInGap;
startLoop = endPos+1; // -> postpone start
}
size_t lastCovered = bitmap.GetLastPos();
if (endPos > lastCovered || lastCovered == NOT_FOUND) lastCovered = endPos;
for(size_t currPos = startLoop; currPos <= lastCovered ; currPos++)
{
// start of a new gap?
if(startGap == notInGap && bitmap.GetValue(currPos) == false && (currPos < startPos || currPos > endPos))
{
startGap = currPos;
}
// end of a gap?
else if(startGap != notInGap && (bitmap.GetValue(currPos) == true || (startPos <= currPos && currPos <= endPos)))
{
futureScore += GetScore(startGap, currPos - 1);
startGap = notInGap;
}
}
// coverage ending with gap?
if (lastCovered != bitmap.GetSize() - 1)
{
futureScore += GetScore(lastCovered+1, bitmap.GetSize() - 1);
}
return futureScore;
}
TO_STRING_BODY(SquareMatrix);
}
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