org.chocosolver.samples.integer.KnightTourProblem_Circuit Maven / Gradle / Ivy

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/**
 * Copyright (c) 2015, 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
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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package org.chocosolver.samples.integer;

import gnu.trove.list.array.TIntArrayList;
import org.chocosolver.samples.AbstractProblem;
import org.chocosolver.samples.graph.input.HCP_Utils;
import org.chocosolver.solver.Solver;
import org.chocosolver.solver.constraints.ICF;
import org.chocosolver.solver.search.loop.monitors.SMF;
import org.chocosolver.solver.search.strategy.ISF;
import org.chocosolver.solver.variables.IntVar;
import org.chocosolver.solver.variables.VF;
import org.kohsuke.args4j.Option;

/**
 * Solves the Knight's Tour Problem
 *
 * @author Jean-Guillaume Fages
 * @since Oct. 2012
 */
public class KnightTourProblem_Circuit extends AbstractProblem {

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

    @Option(name = "-tl", usage = "time limit.", required = false)
    private long limit = 30000;
    private IntVar[] succ;

    //***********************************************************************************
    // METHODS
    //***********************************************************************************

    public static void main(String[] args) {
        new KnightTourProblem_Circuit().execute(args);
    }

    @Override
    public void createSolver() {
        solver = new Solver("solving the Hamiltonian Cycle Problem");
    }

    @Override
    public void buildModel() {
        boolean[][] matrix = HCP_Utils.generateKingTourInstance(40);
        int n = matrix.length;
		succ = new IntVar[n];
		TIntArrayList values = new TIntArrayList();
        for (int i = 0; i < n; i++) {
			values.clear();
            for (int j = 0; j < n; j++) {
                if (matrix[i][j]) {
					values.add(j);
                }
            }
			succ[i] = VF.enumerated("succ_"+i,values.toArray(),solver);
        }
        solver.post(ICF.circuit(succ,0));
    }

    @Override
    public void configureSearch() {
		SMF.limitTime(solver, limit);
		solver.set(ISF.custom(
				ISF.minDomainSize_var_selector(),
                var -> {
                    int ub = var.getUB();
                    int size = succ.length + 1;
                    int val = -1;
                    for (int j = var.getLB(); j <= ub; j = var.nextValue(j)) {
                        if (succ[j].getDomainSize() < size) {
                            val = j;
                            size = succ[j].getDomainSize();
                        }
                    }
                    return val;
                },
				succ
		));
    }

    @Override
    public void solve() {
        solver.findSolution();
    }

    @Override
    public void prettyOut() {}
}