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}