001package org.cpsolver.exam.criteria;
002
003import java.util.Collection;
004import java.util.Set;
005
006import org.cpsolver.exam.criteria.additional.PeriodViolation;
007import org.cpsolver.exam.model.Exam;
008import org.cpsolver.exam.model.ExamPeriodPlacement;
009import org.cpsolver.exam.model.ExamPlacement;
010import org.cpsolver.ifs.assignment.Assignment;
011import org.cpsolver.ifs.solver.Solver;
012import org.cpsolver.ifs.util.DataProperties;
013
014
015/**
016 * Cost for using a period. See {@link ExamPeriodPlacement#getPenalty()} for more details.
017 * <br><br>
018 * A weight for period penalty can be set by problem property
019 * Exams.PeriodWeight, or in the input xml file, property periodWeight.
020 * 
021 * <br>
022 * 
023 * @version ExamTT 1.3 (Examination Timetabling)<br>
024 *          Copyright (C) 2008 - 2014 Tomáš Müller<br>
025 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
026 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
027 * <br>
028 *          This library is free software; you can redistribute it and/or modify
029 *          it under the terms of the GNU Lesser General Public License as
030 *          published by the Free Software Foundation; either version 3 of the
031 *          License, or (at your option) any later version. <br>
032 * <br>
033 *          This library is distributed in the hope that it will be useful, but
034 *          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. <br>
037 * <br>
038 *          You should have received a copy of the GNU Lesser General Public
039 *          License along with this library; if not see
040 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
041 */
042public class PeriodPenalty extends ExamCriterion {
043    protected Integer iSoftPeriods = null;
044    
045    @Override
046    public boolean init(Solver<Exam, ExamPlacement> solver) {
047        if (super.init(solver)) {
048            iSoftPeriods = solver.getProperties().getPropertyInteger("Exam.SoftPeriods", null);
049            if (iSoftPeriods != null) {
050                PeriodViolation pv = new PeriodViolation();
051                getModel().addCriterion(pv);
052                return pv.init(solver);
053            }
054        }
055        return true;
056    }
057    
058    @Override
059    public String getWeightName() {
060        return "Exams.PeriodWeight";
061    }
062    
063    @Override
064    public String getXmlWeightName() {
065        return "periodWeight";
066    }
067    
068    @Override
069    public double getWeightDefault(DataProperties config) {
070        return 1.0;
071    }
072    
073    @Override
074    public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) {
075        return (iSoftPeriods == null || (value.getPeriodPlacement().getExamPenalty() != iSoftPeriods &&  value.getPeriodPlacement().getPeriod().getPenalty() != iSoftPeriods) ? value.getPeriodPlacement().getPenalty() : 0.0);
076    }
077
078    @Override
079    public double[] getBounds(Assignment<Exam, ExamPlacement> assignment, Collection<Exam> variables) {
080        double[] bounds = new double[] { 0.0, 0.0 };
081        for (Exam exam : variables) {
082            if (!exam.getPeriodPlacements().isEmpty()) {
083                int minPenalty = Integer.MAX_VALUE, maxPenalty = Integer.MIN_VALUE;
084                for (ExamPeriodPlacement periodPlacement : exam.getPeriodPlacements()) {
085                    if (iSoftPeriods != null && (periodPlacement.getExamPenalty() == iSoftPeriods || periodPlacement.getPeriod().getPenalty() == iSoftPeriods)) continue;
086                    minPenalty = Math.min(minPenalty, periodPlacement.getPenalty());
087                    maxPenalty = Math.max(maxPenalty, periodPlacement.getPenalty());
088                }
089                bounds[0] += minPenalty;
090                bounds[1] += maxPenalty;
091            }
092        }
093        return bounds;
094    }
095    
096    @Override
097    public String toString(Assignment<Exam, ExamPlacement> assignment) {
098        return "PP:" + sDoubleFormat.format(getValue(assignment));
099    }
100}