001 package net.sf.cpsolver.exam.criteria;
002
003 import java.util.Map;
004 import java.util.Set;
005
006 import net.sf.cpsolver.exam.model.Exam;
007 import net.sf.cpsolver.exam.model.ExamPlacement;
008 import net.sf.cpsolver.ifs.solver.Solver;
009 import net.sf.cpsolver.ifs.util.DataProperties;
010
011 /**
012 * Perturbation penalty. I.e., penalty for using a different examination period than
013 * initial. Only applicable when {@link PerturbationPenalty#isMPP()} is true (minimal
014 * perturbation problem).
015 * <br><br>
016 * A weight of perturbations (i.e., a penalty for an
017 * assignment of an exam to a place different from the initial one) can be
018 * set by problem property Exams.PerturbationWeight, or in the input xml
019 * file, property perturbationWeight).
020 *
021 * <br>
022 *
023 * @version ExamTT 1.2 (Examination Timetabling)<br>
024 * Copyright (C) 2008 - 2012 Tomas Muller<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 */
042 public class PerturbationPenalty extends ExamCriterion {
043 private boolean iMPP = false;
044
045 @Override
046 public boolean init(Solver<Exam, ExamPlacement> solver) {
047 boolean ret = super.init(solver);
048 iMPP = solver.getProperties().getPropertyBoolean("General.MPP", iMPP);
049 return ret;
050 }
051
052 @Override
053 public String getWeightName() {
054 return "Exams.PerturbationWeight";
055 }
056
057 @Override
058 public String getXmlWeightName() {
059 return "perturbationWeight";
060 }
061
062 @Override
063 public double getWeightDefault(DataProperties config) {
064 return 0.01;
065 }
066
067 public boolean isMPP() {
068 return iMPP;
069 }
070
071 @Override
072 public void getXmlParameters(Map<String, String> params) {
073 params.put(getXmlWeightName(), String.valueOf(getWeight()));
074 params.put("mpp", isMPP() ? "true" : "false");
075 }
076
077 @Override
078 public void setXmlParameters(Map<String, String> params) {
079 try {
080 setWeight(Double.valueOf(params.get(getXmlWeightName())));
081 } catch (NumberFormatException e) {} catch (NullPointerException e) {}
082 try {
083 iMPP = "true".equals(params.get("mpp"));
084 } catch (NumberFormatException e) {} catch (NullPointerException e) {}
085 }
086
087 @Override
088 public double getValue(ExamPlacement value, Set<ExamPlacement> conflicts) {
089 if (!isMPP()) return 0;
090 Exam exam = value.variable();
091 ExamPlacement initial = exam.getInitialAssignment();
092 if (initial == null) return 0;
093 return Math.abs(initial.getPeriod().getIndex() - value.getPeriod().getIndex()) * (1 + exam.getSize());
094 }
095
096 @Override
097 public String toString() {
098 return (isMPP() ? "IP:" + sDoubleFormat.format(getValue()) : "");
099 }
100 }