001    package net.sf.cpsolver.ifs.termination;
002    
003    import net.sf.cpsolver.ifs.solution.Solution;
004    import net.sf.cpsolver.ifs.util.DataProperties;
005    
006    /**
007     * General implementation of termination condition.
008     * <br><br>
009     * Solver stops when the solution is complete (all varaibles are assigned) or when a timeout
010     * is reached (expressed either by the number of iterations or by a time).
011     * <br><br>
012     * Parameters:
013     * <br>
014     * <table border='1'><tr><th>Parameter</th><th>Type</th><th>Comment</th></tr>
015     * <tr><td>Termination.StopWhenComplete</td><td>{@link Double}</td><td>if true, solver stops when a complete solution is found</td></tr>
016     * <tr><td>Termination.MaxIters</td><td>{@link Integer}</td><td>if zero or positive, solver stops when the given number of iteration is reached</td></tr>
017     * <tr><td>Termination.TimeOut</td><td>{@link Double}</td><td>if zero or positive, solver stops when the given timeout (given in seconds) is reached</td></tr>
018     * </table>
019     *
020     * @see net.sf.cpsolver.ifs.solver.Solver
021     *
022     * @version
023     * IFS 1.1 (Iterative Forward Search)<br>
024     * Copyright (C) 2006 Tomáš Müller<br>
025     * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
026     * Lazenska 391, 76314 Zlin, Czech Republic<br>
027     * <br>
028     * This library is free software; you can redistribute it and/or
029     * modify it under the terms of the GNU Lesser General Public
030     * License as published by the Free Software Foundation; either
031     * version 2.1 of the License, or (at your option) any later version.
032     * <br><br>
033     * This library is distributed in the hope that it will be useful,
034     * but WITHOUT ANY WARRANTY; without even the implied warranty of
035     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
036     * Lesser General Public License for more details.
037     * <br><br>
038     * You should have received a copy of the GNU Lesser General Public
039     * License along with this library; if not, write to the Free Software
040     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
041     **/
042    public class GeneralTerminationCondition implements TerminationCondition {
043        protected static org.apache.log4j.Logger sLogger = org.apache.log4j.Logger.getLogger(GeneralTerminationCondition.class);
044        private int iMaxIter;
045        private double iTimeOut;
046        private boolean iStopWhenComplete;
047        
048        public GeneralTerminationCondition(DataProperties properties) {
049            iMaxIter = properties.getPropertyInt("Termination.MaxIters",-1);
050            iTimeOut = properties.getPropertyDouble("Termination.TimeOut",  -1.0);
051            iStopWhenComplete = properties.getPropertyBoolean("Termination.StopWhenComplete", false);
052        }
053        
054        public boolean canContinue(Solution currentSolution) {
055            if (iMaxIter>=0 && currentSolution.getIteration()>=iMaxIter) {
056                sLogger.info("Maximum number of iteration reached.");
057                return false;
058            }
059            if (iTimeOut>=0 && currentSolution.getTime()>iTimeOut) {
060                sLogger.info("Timeout reached.");
061                return false;
062            }
063            if (iStopWhenComplete || (iMaxIter<0 && iTimeOut<0)) {
064                boolean ret = (currentSolution.getModel().nrUnassignedVariables()!=0);
065                if (!ret) sLogger.info("Complete solution found.");
066                return ret;
067            }
068            return true;
069        }
070    }