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Open-source constraint solver.
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/**
 * Copyright (c) 2016, Ecole des Mines de Nantes
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by the .
 * 4. Neither the name of the  nor the
 *    names of its contributors may be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY  ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL  BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.chocosolver.solver.constraints.nary.alldifferent;

import org.chocosolver.solver.constraints.Propagator;
import org.chocosolver.solver.constraints.PropagatorPriority;
import org.chocosolver.solver.constraints.nary.alldifferent.algo.AlgoAllDiffAC;
import org.chocosolver.solver.exception.ContradictionException;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.util.ESat;

/**
 * Propagator for AllDifferent AC constraint for integer variables
 * 
 * Uses Regin algorithm
 * Runs in O(m.n) worst case time for the initial propagation
 * but has a good average behavior in practice
 * 

 * Runs incrementally for maintaining a matching
 * 
 *
 * @author Jean-Guillaume Fages
 */
public class PropAllDiffAC extends Propagator {

    //***********************************************************************************
    // VARIABLES
    //***********************************************************************************

    protected AlgoAllDiffAC filter;

    //***********************************************************************************
    // CONSTRUCTORS
    //***********************************************************************************

    /**
     * AllDifferent constraint for integer variables
     * enables to control the cardinality of the matching
     *
     * @param variables array of integer variables
     */
    public PropAllDiffAC(IntVar[] variables) {
        super(variables, PropagatorPriority.QUADRATIC, false);
        this.filter = new AlgoAllDiffAC(variables, this);
    }

    //***********************************************************************************
    // PROPAGATION
    //***********************************************************************************

    @Override
    public void propagate(int evtmask) throws ContradictionException {
        filter.propagate();
    }

    @Override
    public ESat isEntailed() {
        return ESat.TRUE; // redundant propagator (used with PropAllDiffInst)
    }

}