    001package org.cpsolver.coursett.criteria.placement;
    002
    003import java.util.Collection;
    004import java.util.Map;
    005import java.util.Set;
    006
    007import org.cpsolver.coursett.model.Lecture;
    008import org.cpsolver.coursett.model.Placement;
    009import org.cpsolver.ifs.assignment.Assignment;
    010import org.cpsolver.ifs.extension.ConflictStatistics;
    011import org.cpsolver.ifs.extension.Extension;
    012import org.cpsolver.ifs.solution.Solution;
    013import org.cpsolver.ifs.solution.SolutionListener;
    014import org.cpsolver.ifs.solver.Solver;
    015
    016
    017/**
    018 * Hard conflicts weighted by the conflict-based statistics (past occurrences).
    019 * <br>
    020 *
    021 * @author  Tomáš Müller
    022 * @version CourseTT 1.3 (University Course Timetabling)<br>
    023 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
    024 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    025 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    026 * <br>
    027 *          This library is free software; you can redistribute it and/or modify
    028 *          it under the terms of the GNU Lesser General Public License as
    029 *          published by the Free Software Foundation; either version 3 of the
    030 *          License, or (at your option) any later version. <br>
    031 * <br>
    032 *          This library is distributed in the hope that it will be useful, but
    033 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    034 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    035 *          Lesser General Public License for more details. <br>
    036 * <br>
    037 *          You should have received a copy of the GNU Lesser General Public
    038 *          License along with this library; if not see
    039 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    040 */
    041public class WeightedHardConflicts extends PlacementSelectionCriterion implements SolutionListener<Lecture, Placement> {
    042    protected ConflictStatistics<Lecture, Placement> iStat = null;
    043
    044    @Override
    045    public boolean init(Solver<Lecture, Placement> solver) {
    046        super.init(solver);
    047        for (Extension<Lecture, Placement> extension : solver.getExtensions()) {
    048            if (ConflictStatistics.class.isInstance(extension))
    049                iStat = (ConflictStatistics<Lecture, Placement>) extension;
    050        }
    051        solver.currentSolution().addSolutionListener(this);
    052        return true;
    053    }
    054
    055    @Override
    056    public String getPlacementSelectionWeightName() {
    057        return "Placement.NrConflictsWeight";
    058    }
    059
    060    @Override
    061    public double getValue(Assignment<Lecture, Placement> assignment, Placement value, Set<Placement> conflicts) {
    062        if (iStat != null && conflicts != null && !conflicts.isEmpty()) {
    063            return iStat.countRemovals(((IterationContext)getContext(assignment)).getIteration(), conflicts, value);
    064        } else {
    065            return 0.0;
    066        }
    067    }
    068
    069    @Override
    070    public double getPlacementSelectionWeightDefault(int level) {
    071        return (level == 0 ? 3.0 : 0.0);
    072    }
    073
    074    @Override
    075    public void solutionUpdated(Solution<Lecture, Placement> solution) {
    076        ((IterationContext)getContext(solution.getAssignment())).setIteration(solution.getIteration());
    077    }
    078
    079    @Override
    080    public void getInfo(Solution<Lecture, Placement> solution, Map<String, String> info) {
    081    }
    082
    083    @Override
    084    public void getInfo(Solution<Lecture, Placement> solution, Map<String, String> info, Collection<Lecture> variables) {
    085    }
    086
    087    @Override
    088    public void bestCleared(Solution<Lecture, Placement> solution) {
    089        ((IterationContext)getContext(solution.getAssignment())).setIteration(solution.getIteration());
    090    }
    091
    092    @Override
    093    public void bestSaved(Solution<Lecture, Placement> solution) {
    094        ((IterationContext)getContext(solution.getAssignment())).setIteration(solution.getIteration());
    095    }
    096
    097    @Override
    098    public void bestRestored(Solution<Lecture, Placement> solution) {
    099        ((IterationContext)getContext(solution.getAssignment())).setIteration(solution.getIteration());
    100    }
    101
    102    @Override
    103    public ValueContext createAssignmentContext(Assignment<Lecture, Placement> assignment) {
    104        return new IterationContext(assignment);
    105    }
    106
    107    public class IterationContext extends ValueContext {
    108        protected long iIteration = 0;
    109
    110        protected IterationContext(Assignment<Lecture, Placement> assignment) {
    111            super(assignment);
    112        }
    113
    114        public void setIteration(long iteration) {
    115            iIteration = iteration;
    116        }
    117
    118        public long getIteration() {
    119            return iIteration;
    120        }
    121    }
    122}