Impact.h

// Impact.h -- The `maximum/minimum impact' variable ordering
// heuristic interface.

/*
 * Copyright (C) 2004 Tudor Hulubei <tudor@hulubei.net>.
 *
 * 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, 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., 59 Temple Place, Suite 330, Boston, MA,
 * 02111-1307, USA.
 */

// $Id: Impact_8h-source.html,v 1.1 2005/05/25 12:37:18 tudor Exp $

#ifndef _CSP_HEURISTICS_VARIABLE_Impact_H
#define _CSP_HEURISTICS_VARIABLE_Impact_H


#include "../../caches/ConflictCounts.h"


CSP_NAMESPACE_BEGIN(csp);
CSP_NAMESPACE_BEGIN(heuristics);
CSP_NAMESPACE_BEGIN(variables);


class ImpactLT :
    public StrictWeakVariableOrdering
{
  public:
    ImpactLT(caches::ConflictCounts& conflictCounts) :
        m_conflictCounts(conflictCounts) {}

    bool operator()(const Variable* variable0, const Variable* variable1);

  private:
    caches::ConflictCounts& m_conflictCounts;
};


class ImpactGT :
    public StrictWeakVariableOrdering
{
  public:
    ImpactGT(caches::ConflictCounts& conflictCounts) :
        m_conflictCounts(conflictCounts) {}

    bool operator()(const Variable* variable0, const Variable* variable1);

  private:
    caches::ConflictCounts& m_conflictCounts;
};


class ImpactEQ :
    public StrictWeakVariableOrdering
{
  public:
    ImpactEQ(caches::ConflictCounts& conflictCounts) :
        m_conflictCounts(conflictCounts),
        m_previousVariable0(0),
        m_previousVariable1(0),
        m_previousTotalConflictCount0(0),
        m_previousTotalConflictCount1(0) {}

    bool operator()(const Variable* variable0, const Variable* variable1);

    void reset()
    {
        m_previousVariable0 = 0;
        m_previousVariable1 = 0;
        m_previousTotalConflictCount0 = 0;
        m_previousTotalConflictCount1 = 0;
    }

  private:
    caches::ConflictCounts& m_conflictCounts;

    const Variable* m_previousVariable0;
    const Variable* m_previousVariable1;

    size_t m_previousTotalConflictCount0;
    size_t m_previousTotalConflictCount1;
};


class CSP_API Impact :
    public VariableOH
{
  public:
    enum Preference
    {
        Minimum,

        Maximum
    };

    Impact(
        Decomposition& decomposition,
        const vector<pair<double, double> >& intervals,
        double quality = 1,
        Preference preference = Maximum,
        bool dynamic = false);

    ~Impact();

    virtual void init(const vlist_type& /*uninstantiatedVariables*/);
    
    virtual void done();

    virtual void select(vlist_type& selectable, vlist_type& selected);

  private:
    Impact(const Impact&);

    Impact& operator=(const Impact&);

    Preference m_preference;

    bool m_dynamic;

    caches::ConflictCounts m_conflictCounts;

    ImpactLT m_compareLT;

    ImpactGT m_compareGT;

    ImpactEQ m_compareEQ;
};


CSP_NAMESPACE_END(variables);
CSP_NAMESPACE_END(heuristics);
CSP_NAMESPACE_END(csp);


#endif // _CSP_HEURISTICS_VARIABLE_Impact_H

// Local Variables:
// mode: C++
// End:

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