001    package net.sf.cpsolver.coursett.criteria.placement;
002    
003    import java.util.Collection;
004    import java.util.Map;
005    import java.util.Set;
006    
007    import net.sf.cpsolver.coursett.model.Lecture;
008    import net.sf.cpsolver.coursett.model.Placement;
009    import net.sf.cpsolver.ifs.extension.ConflictStatistics;
010    import net.sf.cpsolver.ifs.extension.Extension;
011    import net.sf.cpsolver.ifs.solution.Solution;
012    import net.sf.cpsolver.ifs.solution.SolutionListener;
013    import 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 Tomas Muller<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     */
038    public 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    }