    001package org.cpsolver.ifs.termination;
    002
    003import org.cpsolver.ifs.model.Value;
    004import org.cpsolver.ifs.model.Variable;
    005import org.cpsolver.ifs.solution.Solution;
    006import org.cpsolver.ifs.util.DataProperties;
    007
    008/**
    009 * General implementation of termination condition. <br>
    010 * <br>
    011 * Solver stops when the solution is complete (all varaibles are assigned) or
    012 * when a timeout is reached (expressed either by the number of iterations or by
    013 * a time). <br>
    014 * <br>
    015 * Parameters: <br>
    016 * <table border='1'><caption>Related Solver Parameters</caption>
    017 * <tr>
    018 * <th>Parameter</th>
    019 * <th>Type</th>
    020 * <th>Comment</th>
    021 * </tr>
    022 * <tr>
    023 * <td>Termination.StopWhenComplete</td>
    024 * <td>{@link Double}</td>
    025 * <td>if true, solver stops when a complete solution is found</td>
    026 * </tr>
    027 * <tr>
    028 * <td>Termination.MaxIters</td>
    029 * <td>{@link Integer}</td>
    030 * <td>if zero or positive, solver stops when the given number of iteration is
    031 * reached</td>
    032 * </tr>
    033 * <tr>
    034 * <td>Termination.TimeOut</td>
    035 * <td>{@link Double}</td>
    036 * <td>if zero or positive, solver stops when the given timeout (given in
    037 * seconds) is reached</td>
    038 * </tr>
    039 * </table>
    040 *
    041 * @see org.cpsolver.ifs.solver.Solver
    042 *
    043 * @author  Tomáš Müller
    044 * @version IFS 1.3 (Iterative Forward Search)<br>
    045 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
    046 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    047 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    048 * <br>
    049 *          This library is free software; you can redistribute it and/or modify
    050 *          it under the terms of the GNU Lesser General Public License as
    051 *          published by the Free Software Foundation; either version 3 of the
    052 *          License, or (at your option) any later version. <br>
    053 * <br>
    054 *          This library is distributed in the hope that it will be useful, but
    055 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    056 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    057 *          Lesser General Public License for more details. <br>
    058 * <br>
    059 *          You should have received a copy of the GNU Lesser General Public
    060 *          License along with this library; if not see <a href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>.
    061 *
    062 * @param <V> Variable
    063 * @param <T> Value
    064 **/
    065public class GeneralTerminationCondition<V extends Variable<V, T>, T extends Value<V, T>> implements
    066        TerminationCondition<V, T> {
    067    protected static org.apache.logging.log4j.Logger sLogger = org.apache.logging.log4j.LogManager.getLogger(GeneralTerminationCondition.class);
    068    private int iMaxIter;
    069    private double iTimeOut;
    070    private boolean iStopWhenComplete;
    071
    072    public GeneralTerminationCondition(DataProperties properties) {
    073        iMaxIter = properties.getPropertyInt("Termination.MaxIters", -1);
    074        iTimeOut = properties.getPropertyDouble("Termination.TimeOut", -1.0);
    075        iStopWhenComplete = properties.getPropertyBoolean("Termination.StopWhenComplete", false);
    076    }
    077
    078    @Override
    079    public boolean canContinue(Solution<V, T> currentSolution) {
    080        if (iMaxIter >= 0 && currentSolution.getIteration() >= iMaxIter) {
    081            sLogger.info("Maximum number of iteration reached.");
    082            return false;
    083        }
    084        if (iTimeOut >= 0 && currentSolution.getTime() > iTimeOut) {
    085            sLogger.info("Timeout reached.");
    086            return false;
    087        }
    088        if (iStopWhenComplete || (iMaxIter < 0 && iTimeOut < 0)) {
    089            boolean ret = (currentSolution.getAssignment().nrUnassignedVariables(currentSolution.getModel()) != 0);
    090            if (!ret)
    091                sLogger.info("Complete solution found.");
    092            return ret;
    093        }
    094        return true;
    095    }
    096}