values/Branching.h

// Branching.h -- The `maximum/minimum branching' value 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: values_2Branching_8h-source.html,v 1.1 2005/05/25 12:37:18 tudor Exp $

#ifndef _CSP_HEURISTICS_VALUE_Branching_H
#define _CSP_HEURISTICS_VALUE_Branching_H


#include "../../caches/BranchingFactors.h"


CSP_NAMESPACE_BEGIN(csp);
CSP_NAMESPACE_BEGIN(heuristics);
CSP_NAMESPACE_BEGIN(values);


class BranchingFactorLT :
    public StrictWeakValueOrdering
{
  public:
    BranchingFactorLT(caches::BranchingFactors& branchingFactors) :
        m_branchingFactors(branchingFactors) {}

    bool operator()(const Value* value0, const Value* value1)
    {
        return
            m_branchingFactors.branchingFactor(*value0) <
            m_branchingFactors.branchingFactor(*value1);
    }

  private:
    caches::BranchingFactors& m_branchingFactors;
};


class BranchingFactorGT :
    public StrictWeakValueOrdering
{
  public:
    BranchingFactorGT(caches::BranchingFactors& branchingFactors) :
        m_branchingFactors(branchingFactors) {}

    bool operator()(const Value* value0, const Value* value1)
    {
        return
            m_branchingFactors.branchingFactor(*value0) >
            m_branchingFactors.branchingFactor(*value1);
    }

  private:
    caches::BranchingFactors& m_branchingFactors;
};


class BranchingFactorEQ :
    public StrictWeakValueOrdering
{
  public:
    BranchingFactorEQ(caches::BranchingFactors& branchingFactors) :
        m_branchingFactors(branchingFactors),
        m_previousValue0(0),
        m_previousValue1(0),
        m_previousBranchingFactor0(0),
        m_previousBranchingFactor1(0) {}

    bool operator()(const Value* value0, const Value* value1);

    void reset()
    {
        m_previousValue0 = 0;
        m_previousValue1 = 0;
        m_previousBranchingFactor0 = 0;
        m_previousBranchingFactor1 = 0;
    }

  private:
    caches::BranchingFactors& m_branchingFactors;

    const Value* m_previousValue0;
    const Value* m_previousValue1;

    size_t m_previousBranchingFactor0;
    size_t m_previousBranchingFactor1;
};


class CSP_API Branching :
    public ValueOH
{
  public:
    enum Preference
    {
        Minimum,

        Maximum
    };

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

    virtual void dynamicInit(Variable& variable, Domain& selectable);

    virtual void dynamicDone(Variable& variable);

    virtual void select(
        Domain& selectable,
        Domain& selected,
        Variable& variable);

    virtual bool better(const Value& value0, const Value& value1);

    virtual bool equal(const Value& value0, const Value& value1);

    virtual void sort(
        Domain& original,
        Domain& sorted,
        Variable& variable);

    virtual long double score(Variable& variable, const Value& value);

  private:
    Branching(const Branching&);

    Branching& operator=(const Branching&);

    Preference m_preference;

    caches::BranchingFactors m_branchingFactors;

    BranchingFactorLT m_compareLT;

    BranchingFactorGT m_compareGT;

    BranchingFactorEQ m_compareEQ;
};


CSP_NAMESPACE_END(values);
CSP_NAMESPACE_END(heuristics);
CSP_NAMESPACE_END(csp);


#endif // _CSP_HEURISTICS_VALUE_Branching_H

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

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