AC1.h

// AC1.h -- The AC-1 filter interface.

/*
 * Copyright (C) 1998 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: AC1_8h-source.html,v 1.1 2005/05/25 12:37:17 tudor Exp $

#ifndef _CSP_FILTERS_AC1_H
#define _CSP_FILTERS_AC1_H


CSP_NAMESPACE_BEGIN(csp);
CSP_NAMESPACE_BEGIN(filters);


class CSP_API AC1 :
    public Filter
{
  public:
    AC1(Problem& problem, Retraction& retraction) :
        Filter(L"Arc Consistency 1", L"AC-1", problem, retraction) {}
    ~AC1() {}

    virtual bool init(
        const vlist_type& uninstantiatedVariables,
        bool propagate = true);
    virtual void done() { Filter::done(); }

    virtual bool restoresArcConsistency() const { return true; }

    virtual bool propagate(
        const vlist_type& uninstantiatedVariables,
        const vlist_type& modifiedVariables,
        const bool keepChanges = true);

  private:
    AC1(const AC1&);

    AC1& operator=(const AC1&);

    bool prune(Constraint& constraint, Variable& variable);

    bool pruneVariablesInList(const vlist_type& vl);

    Domain m_diffs;

    bool m_changed;
};


CSP_NAMESPACE_END(filters);
CSP_NAMESPACE_END(csp);


#endif // _CSP_FILTERS_AC1_H

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