gsearch.cpp

来自「一个由Mike Gashler完成的机器学习方面的includes neural」· C++ 代码 · 共 147 行

/*
	Copyright (C) 2006, Mike Gashler

	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.

	see http://www.gnu.org/copyleft/lesser.html
*/

#include "GSearch.h"
#include <string.h>

GRealVectorCritic::GRealVectorCritic(int nVectorSize)
{
	m_nVectorSize = nVectorSize;
	m_dBestError = 1e100;
	m_pBestYet = new double[nVectorSize];
	int i;
	for(i = 0; i < nVectorSize; i++)
		m_pBestYet[i] = 0;
}

GRealVectorCritic::~GRealVectorCritic()
{
	delete(m_pBestYet);
}

double GRealVectorCritic::Critique(double* pVector)
{
	double dError = ComputeError(pVector);
	if(dError < m_dBestError)
	{
		m_dBestError = dError;
		memcpy(m_pBestYet, pVector, sizeof(double) * m_nVectorSize);
	}
	return dError;
}

// -------------------------------------------------------

GRealVectorSearch::GRealVectorSearch(GRealVectorCritic* pCritic)
{
	m_pCritic = pCritic;
}

/*virtual*/ GRealVectorSearch::~GRealVectorSearch()
{
}

// -------------------------------------------------------

class GAction
{
protected:
	int m_nAction;
	GAction* m_pPrev;
	unsigned int m_nRefs;

	~GAction()
	{
		if(m_pPrev)
			m_pPrev->Release(); // todo: this could overflow the stack with recursion
	}
public:
	GAction(int nAction, GAction* pPrev)
	 : m_nAction(nAction), m_nRefs(0)
	{
		m_pPrev = pPrev;
		if(pPrev)
			pPrev->AddRef();
	}

	void AddRef()
	{
		m_nRefs++;
	}

	void Release()
	{
		if(--m_nRefs == 0)
			delete(this);
	}

	GAction* GetPrev() { return m_pPrev; }
	int GetAction() { return m_nAction; }
};

// -------------------------------------------------------

GActionPath::GActionPath(GActionPathState* pState) : m_pLastAction(NULL), m_nPathLen(0)
{
	m_pHeadState = pState;
}

GActionPath::~GActionPath()
{
	if(m_pLastAction)
		m_pLastAction->Release();
	delete(m_pHeadState);
}

void GActionPath::DoAction(int nAction)
{
	GAction* pPrevAction = m_pLastAction;
	m_pLastAction = new GAction(nAction, pPrevAction);
	m_pLastAction->AddRef(); // referenced by m_pLastAction
	if(pPrevAction)
		pPrevAction->Release(); // no longer referenced by m_pLastAction
	m_nPathLen++;
	m_pHeadState->PerformAction(nAction);
}

GActionPath* GActionPath::Fork()
{
	GActionPath* pNewPath = new GActionPath(m_pHeadState->Copy());
	pNewPath->m_nPathLen = m_nPathLen;
	pNewPath->m_pLastAction = m_pLastAction;
	if(m_pLastAction)
		m_pLastAction->AddRef();
	return pNewPath;
}

void GActionPath::GetPath(int nCount, int* pOutBuf)
{
	while(nCount > m_nPathLen)
		pOutBuf[--nCount] = -1;
	int i = m_nPathLen;
	GAction* pAction = m_pLastAction;
	while(i > nCount)
	{
		i--;
		pAction = pAction->GetPrev();
	}
	while(i > 0)
	{
		pOutBuf[--i] = pAction->GetAction();
		pAction = pAction->GetPrev();
	}
}

double GActionPath::Critique()
{
	return m_pHeadState->CritiquePath(m_nPathLen, m_pLastAction);
}