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.ExamPlacement;
007 import 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 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 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 }