    001package net.sf.cpsolver.coursett.criteria.placement;
    002
    003import java.util.Collection;
    004import java.util.Map;
    005import java.util.Set;
    006
    007import net.sf.cpsolver.coursett.model.Lecture;
    008import net.sf.cpsolver.coursett.model.Placement;
    009import net.sf.cpsolver.ifs.extension.ConflictStatistics;
    010import net.sf.cpsolver.ifs.extension.Extension;
    011import net.sf.cpsolver.ifs.solution.Solution;
    012import net.sf.cpsolver.ifs.solution.SolutionListener;
    013import net.sf.cpsolver.ifs.solver.Solver;
    014
    015/**
    016 * Hard conflicts weighted by the conflict-based statistics (past occurrences).
    017 * <br>
    018 *
    019 * @version CourseTT 1.2 (University Course Timetabling)<br>
    020 *          Copyright (C) 2006 - 2011 Tomáš Müller<br>
    021 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    022 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    023 * <br>
    024 *          This library is free software; you can redistribute it and/or modify
    025 *          it under the terms of the GNU Lesser General Public License as
    026 *          published by the Free Software Foundation; either version 3 of the
    027 *          License, or (at your option) any later version. <br>
    028 * <br>
    029 *          This library is distributed in the hope that it will be useful, but
    030 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    031 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    032 *          Lesser General Public License for more details. <br>
    033 * <br>
    034 *          You should have received a copy of the GNU Lesser General Public
    035 *          License along with this library; if not see
    036 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    037 */
    038public class WeightedHardConflicts extends PlacementSelectionCriterion implements SolutionListener<Lecture, Placement> {
    039    protected ConflictStatistics<Lecture, Placement> iStat = null;
    040    protected long iIteration = 0;
    041
    042    @Override
    043    public boolean init(Solver<Lecture, Placement> solver) {
    044        super.init(solver);
    045        for (Extension<Lecture, Placement> extension : solver.getExtensions()) {
    046            if (ConflictStatistics.class.isInstance(extension))
    047                iStat = (ConflictStatistics<Lecture, Placement>) extension;
    048        }
    049        solver.currentSolution().addSolutionListener(this);
    050        return true;
    051    }
    052
    053    @Override
    054    public String getPlacementSelectionWeightName() {
    055        return "Placement.NrConflictsWeight";
    056    }
    057
    058    @Override
    059    public double getValue(Placement value, Set<Placement> conflicts) {
    060        return (iStat == null || conflicts == null ? 0.0 : iStat.countRemovals(iIteration, conflicts, value));
    061    }
    062
    063    @Override
    064    public double getPlacementSelectionWeightDefault(int level) {
    065        return (level == 0 ? 3.0 : 0.0);
    066    }
    067
    068    @Override
    069    public void solutionUpdated(Solution<Lecture, Placement> solution) {
    070        iIteration = solution.getIteration();
    071    }
    072
    073    @Override
    074    public void getInfo(Solution<Lecture, Placement> solution, Map<String, String> info) {
    075    }
    076
    077    @Override
    078    public void getInfo(Solution<Lecture, Placement> solution, Map<String, String> info, Collection<Lecture> variables) {
    079    }
    080
    081    @Override
    082    public void bestCleared(Solution<Lecture, Placement> solution) {
    083        iIteration = solution.getIteration();
    084    }
    085
    086    @Override
    087    public void bestSaved(Solution<Lecture, Placement> solution) {
    088        iIteration = solution.getIteration();
    089    }
    090
    091    @Override
    092    public void bestRestored(Solution<Lecture, Placement> solution) {
    093        iIteration = solution.getIteration();
    094    }
    095
    096}