001package org.cpsolver.exam.criteria; 002 003import java.util.Map; 004import java.util.Set; 005 006import org.cpsolver.exam.model.Exam; 007import org.cpsolver.exam.model.ExamModel; 008import org.cpsolver.exam.model.ExamPeriod; 009import org.cpsolver.exam.model.ExamPlacement; 010import org.cpsolver.exam.model.ExamStudent; 011import org.cpsolver.ifs.assignment.Assignment; 012import org.cpsolver.ifs.util.DataProperties; 013 014 015/** 016 * Number of back-to-back student conflicts. I.e., number of cases when 017 * an exam is attended by a student that attends some other exam at 018 * the previous {@link ExamPeriod#prev()} or following 019 * {@link ExamPeriod#next()} period. If 020 * {@link StudentBackToBackConflicts#isDayBreakBackToBack()} is false, back-to-back conflicts 021 * are only considered between consecutive periods that are of the same day. 022 * <br><br> 023 * Back-to-back student conflict weight can be set by problem property 024 * Exams.BackToBackConflictWeight, or in the input xml file, 025 * property backToBackConflictWeight. 026 * 027 * 028 * <br> 029 * 030 * @version ExamTT 1.3 (Examination Timetabling)<br> 031 * Copyright (C) 2008 - 2014 Tomas Muller<br> 032 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 033 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 034 * <br> 035 * This library is free software; you can redistribute it and/or modify 036 * it under the terms of the GNU Lesser General Public License as 037 * published by the Free Software Foundation; either version 3 of the 038 * License, or (at your option) any later version. <br> 039 * <br> 040 * This library is distributed in the hope that it will be useful, but 041 * WITHOUT ANY WARRANTY; without even the implied warranty of 042 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 043 * Lesser General Public License for more details. <br> 044 * <br> 045 * You should have received a copy of the GNU Lesser General Public 046 * License along with this library; if not see 047 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>. 048 */ 049public class StudentBackToBackConflicts extends ExamCriterion { 050 private boolean iDayBreakBackToBack = false; 051 052 @Override 053 public void configure(DataProperties properties) { 054 super.configure(properties); 055 iDayBreakBackToBack = properties.getPropertyBoolean("Exams.IsDayBreakBackToBack", iDayBreakBackToBack); 056 } 057 058 @Override 059 public String getWeightName() { 060 return "Exams.BackToBackConflictWeight"; 061 } 062 063 @Override 064 public String getXmlWeightName() { 065 return "backToBackConflictWeight"; 066 } 067 068 @Override 069 public double getWeightDefault(DataProperties config) { 070 return 10.0; 071 } 072 073 /** 074 * True when back-to-back student conflict is to be encountered when a 075 * student is enrolled into an exam that is on the last period of one day 076 * and another exam that is on the first period of the consecutive day. It 077 * can be set by problem property Exams.IsDayBreakBackToBack, or in the 078 * input xml file, property isDayBreakBackToBack) 079 * @return true if last exam on one day is back-to-back to the first exam of the following day 080 */ 081 public boolean isDayBreakBackToBack() { 082 return iDayBreakBackToBack; 083 } 084 085 /** 086 * True when back-to-back student conflict is to be encountered when a 087 * student is enrolled into an exam that is on the last period of one day 088 * and another exam that is on the first period of the consecutive day. It 089 * can be set by problem property Exams.IsDayBreakBackToBack, or in the 090 * input xml file, property isDayBreakBackToBack) 091 * @param dayBreakBackToBack true if last exam on one day is back-to-back to the first exam of the following day 092 * 093 */ 094 public void setDayBreakBackToBack(boolean dayBreakBackToBack) { 095 iDayBreakBackToBack = dayBreakBackToBack; 096 } 097 098 @Override 099 public void getXmlParameters(Map<String, String> params) { 100 params.put(getXmlWeightName(), String.valueOf(getWeight())); 101 params.put("isDayBreakBackToBack", isDayBreakBackToBack() ? "true" : "false"); 102 } 103 104 @Override 105 public void setXmlParameters(Map<String, String> params) { 106 try { 107 setWeight(Double.valueOf(params.get(getXmlWeightName()))); 108 } catch (NumberFormatException e) {} catch (NullPointerException e) {} 109 try { 110 setDayBreakBackToBack("true".equals(params.get("isDayBreakBackToBack"))); 111 } catch (NumberFormatException e) {} catch (NullPointerException e) {} 112 } 113 114 @Override 115 public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) { 116 Exam exam = value.variable(); 117 int penalty = 0; 118 ExamPeriod period = value.getPeriod(); 119 Map<ExamStudent, Set<Exam>> prev = (period.prev() != null && (isDayBreakBackToBack() || period.prev().getDay() == period.getDay()) ? ((ExamModel)getModel()).getStudentsOfPeriod(assignment, period.prev()) : null); 120 Map<ExamStudent, Set<Exam>> next = (period.next() != null && (isDayBreakBackToBack() || period.next().getDay() == period.getDay()) ? ((ExamModel)getModel()).getStudentsOfPeriod(assignment, period.next()) : null); 121 for (ExamStudent s : exam.getStudents()) { 122 if (prev != null) { 123 Set<Exam> exams = prev.get(s); 124 if (exams != null) { 125 int nrExams = exams.size() + (exams.contains(exam) ? -1 : 0); 126 penalty += nrExams; 127 } 128 } 129 if (next != null) { 130 Set<Exam> exams = next.get(s); 131 if (exams != null) { 132 int nrExams = exams.size() + (exams.contains(exam) ? -1 : 0); 133 penalty += nrExams; 134 } 135 } 136 } 137 /* 138 for (ExamStudent s : exam.getStudents()) { 139 if (period.prev() != null) { 140 if (isDayBreakBackToBack() || period.prev().getDay() == period.getDay()) { 141 Set<Exam> exams = s.getExams(assignment, period.prev()); 142 int nrExams = exams.size() + (exams.contains(exam) ? -1 : 0); 143 penalty += nrExams; 144 } 145 } 146 if (period.next() != null) { 147 if (isDayBreakBackToBack() || period.next().getDay() == period.getDay()) { 148 Set<Exam> exams = s.getExams(assignment, period.next()); 149 int nrExams = exams.size() + (exams.contains(exam) ? -1 : 0); 150 penalty += nrExams; 151 } 152 } 153 } 154 */ 155 return penalty; 156 } 157 158 @Override 159 public String getName() { 160 return "Back-To-Back Conflicts"; 161 } 162 163 @Override 164 public void getInfo(Assignment<Exam, ExamPlacement> assignment, Map<String, String> info) { 165 if (getValue(assignment) != 0.0) 166 info.put(getName(), sDoubleFormat.format(getValue(assignment))); 167 } 168 169 @Override 170 public String toString(Assignment<Exam, ExamPlacement> assignment) { 171 return "BTB:" + sDoubleFormat.format(getValue(assignment)); 172 } 173}