103 lines
3.9 KiB
Java
103 lines
3.9 KiB
Java
/**
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* Copyright (c) 1999-2011, Ecole des Mines de Nantes
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* All rights reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of the Ecole des Mines de Nantes nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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import com.google.ortools.constraintsolver.DecisionBuilder;
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import com.google.ortools.constraintsolver.IntExpr;
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import com.google.ortools.constraintsolver.IntVar;
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import com.google.ortools.constraintsolver.OptimizeVar;
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import com.google.ortools.constraintsolver.SearchMonitor;
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import com.google.ortools.constraintsolver.SolutionCollector;
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import com.google.ortools.constraintsolver.Solver;
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/**
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* Golomb ruler problem
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* <br/>
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*
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* @author Charles Prud'homme
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* @since 17/03/11
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*/
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public class GolombRuler {
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static {
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System.loadLibrary("jniortools");
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}
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/**
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* Golomb Ruler Problem.
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*/
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private static void solve(int m) {
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Solver solver = new Solver("GR " + m);
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IntVar[] ticks =
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solver.makeIntVarArray(m,
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0,
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((m < 31) ? (1 << (m + 1)) - 1 : 9999),
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"ticks");
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solver.addConstraint(solver.makeEquality(ticks[0], 0));
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for (int i = 0; i < ticks.length - 1; i++) {
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solver.addConstraint(solver.makeLess(ticks[i], ticks[i + 1]));
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}
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IntVar[] diff = new IntVar[(m * m - m) / 2];
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for (int k = 0, i = 0; i < m - 1; i++) {
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for (int j = i + 1; j < m; j++, k++) {
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diff[k] = solver.makeDifference(ticks[j], ticks[i]).var();
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solver.addConstraint(
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solver.makeGreaterOrEqual(diff[k], (j - i) * (j - i + 1) / 2));
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}
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}
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solver.addConstraint(solver.makeAllDifferent(diff));
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// break symetries
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if (m > 2) {
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solver.addConstraint(solver.makeLess(diff[0], diff[diff.length - 1]));
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}
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OptimizeVar opt = solver.makeMinimize(ticks[m - 1], 1);
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DecisionBuilder db = solver.makePhase(ticks,
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solver.CHOOSE_MIN_SIZE_LOWEST_MIN,
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solver.ASSIGN_MIN_VALUE);
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SolutionCollector collector = solver.makeLastSolutionCollector();
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collector.add(ticks);
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collector.addObjective(ticks[m - 1]);
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SearchMonitor log = solver.makeSearchLog(10000, opt);
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solver.solve(db, opt, log, collector);
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System.out.println("Optimal solution = " + collector.objectiveValue(0));
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for (int i = 0; i < m; ++i) {
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System.out.print("[" + collector.value(0, ticks[i]) + "] ");
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}
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System.out.println();
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}
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public static void main(String[] args) throws Exception {
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GolombRuler.solve(8);
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}
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}
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