    001package net.sf.cpsolver.exam.criteria;
    002
    003import java.util.Map;
    004import java.util.Set;
    005
    006import net.sf.cpsolver.exam.model.ExamPlacement;
    007import net.sf.cpsolver.ifs.util.DataProperties;
    008
    009/**
    010 * Rotation penalty. I.e., an exam that has been in later period last times tries
    011 * to be in an earlier period.
    012 * <br><br>
    013 * A weight for exam rotation penalty can be set by problem property
    014 * Exams.RotationWeight, or in the input xml file, property examRotationWeight.
    015 *
    016 *
    017 * <br>
    018 *
    019 * @version ExamTT 1.2 (Examination Timetabling)<br>
    020 *          Copyright (C) 2008 - 2012 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 ExamRotationPenalty extends ExamCriterion {
    039    private int iAssignedExamsWithAvgPeriod = 0;
    040    private double iAveragePeriod = 0.0;
    041
    042    @Override
    043    public String getWeightName() {
    044        return "Exams.RotationWeight";
    045    }
    046
    047    @Override
    048    public String getXmlWeightName() {
    049        return "examRotationWeight";
    050    }
    051
    052    @Override
    053    public double getWeightDefault(DataProperties config) {
    054        return 0.001;
    055    }
    056
    057    @Override
    058    public double getValue(ExamPlacement value, Set<ExamPlacement> conflicts) {
    059        if (value.variable().getAveragePeriod() < 0) return 0;
    060        return (1 + value.getPeriod().getIndex()) * (1 + value.variable().getAveragePeriod());
    061    }
    062
    063    @Override
    064    public void beforeUnassigned(long iteration, ExamPlacement value) {
    065        super.beforeUnassigned(iteration, value);
    066        if (value.variable().getAveragePeriod() >= 0) {
    067            iAssignedExamsWithAvgPeriod --;
    068            iAveragePeriod -= value.variable().getAveragePeriod();
    069        }
    070    }
    071
    072    @Override
    073    public void afterAssigned(long iteration, ExamPlacement value) {
    074        super.afterAssigned(iteration, value);
    075        if (value.variable().getAveragePeriod() >= 0) {
    076            iAssignedExamsWithAvgPeriod ++;
    077            iAveragePeriod += value.variable().getAveragePeriod();
    078        }
    079    }
    080
    081    public int nrAssignedExamsWithAvgPeriod() {
    082        return iAssignedExamsWithAvgPeriod;
    083    }
    084
    085    public double averagePeriod() {
    086        return iAveragePeriod / iAssignedExamsWithAvgPeriod;
    087    }
    088
    089    @Override
    090    public void getInfo(Map<String, String> info) {
    091        if (getValue() != 0.0) {
    092            info.put(getName(), sDoubleFormat.format(Math.sqrt(getValue() / iAssignedExamsWithAvgPeriod) - 1));
    093        }
    094    }
    095
    096    @Override
    097    public String toString() {
    098        return "@P:" + sDoubleFormat.format((Math.sqrt(getValue() / iAssignedExamsWithAvgPeriod) - 1));
    099    }
    100}