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.solver.Solver; 013import org.cpsolver.ifs.util.DataProperties; 014 015 016/** 017 * Number of back-to-back distance student conflicts. I.e., number of 018 * cases when an exam is attended by a student that attends some other 019 * exam at the previous {@link ExamPeriod#prev()} or following 020 * {@link ExamPeriod#next()} period and the distance 021 * {@link ExamPlacement#getDistanceInMeters(ExamPlacement)} between these two exams 022 * is greater than {@link ExamModel#getBackToBackDistance()}. Distance 023 * back-to-back conflicts are only considered between consecutive periods 024 * that are of the same day. 025 * <br><br> 026 * Distance back-to-back student conflict weight can be set by problem 027 * property Exams.DistanceBackToBackConflictWeight, or in the 028 * input xml file, property distanceBackToBackConflictWeight. 029 * 030 * <br> 031 * 032 * @version ExamTT 1.3 (Examination Timetabling)<br> 033 * Copyright (C) 2008 - 2014 Tomas Muller<br> 034 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 035 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 036 * <br> 037 * This library is free software; you can redistribute it and/or modify 038 * it under the terms of the GNU Lesser General Public License as 039 * published by the Free Software Foundation; either version 3 of the 040 * License, or (at your option) any later version. <br> 041 * <br> 042 * This library is distributed in the hope that it will be useful, but 043 * WITHOUT ANY WARRANTY; without even the implied warranty of 044 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 045 * Lesser General Public License for more details. <br> 046 * <br> 047 * You should have received a copy of the GNU Lesser General Public 048 * License along with this library; if not see 049 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>. 050 */ 051public class StudentDistanceBackToBackConflicts extends ExamCriterion { 052 private double iBackToBackDistance = -1; 053 054 @Override 055 public boolean init(Solver<Exam, ExamPlacement> solver) { 056 boolean ret = super.init(solver); 057 iBackToBackDistance = solver.getProperties().getPropertyDouble("Exams.BackToBackDistance", iBackToBackDistance); 058 return ret; 059 } 060 061 @Override 062 public String getWeightName() { 063 return "Exams.DistanceBackToBackConflictWeight"; 064 } 065 066 @Override 067 public String getXmlWeightName() { 068 return "distanceBackToBackConflictWeight"; 069 } 070 071 @Override 072 public double getWeightDefault(DataProperties config) { 073 return 25.0; 074 } 075 076 /** 077 * Back-to-back distance. Can be set by 078 * problem property Exams.BackToBackDistance, or in the input xml file, 079 * property backToBackDistance) 080 * @return back-to-back distance in meters 081 */ 082 public double getBackToBackDistance() { 083 return iBackToBackDistance; 084 } 085 086 /** 087 * Back-to-back distance. Can be set by 088 * problem property Exams.BackToBackDistance, or in the input xml file, 089 * property backToBackDistance) 090 * @param backToBackDistance back-to-back distance in meters 091 */ 092 public void setBackToBackDistance(double backToBackDistance) { 093 iBackToBackDistance = backToBackDistance; 094 } 095 096 @Override 097 public void getXmlParameters(Map<String, String> params) { 098 params.put(getXmlWeightName(), String.valueOf(getWeight())); 099 params.put("backToBackDistance", String.valueOf(getBackToBackDistance())); 100 } 101 102 @Override 103 public void setXmlParameters(Map<String, String> params) { 104 try { 105 setWeight(Double.valueOf(params.get(getXmlWeightName()))); 106 } catch (NumberFormatException e) {} catch (NullPointerException e) {} 107 try { 108 setBackToBackDistance(Double.valueOf(params.get("backToBackDistance"))); 109 } catch (NumberFormatException e) {} catch (NullPointerException e) {} 110 } 111 112 @Override 113 public double getValue(Assignment<Exam, ExamPlacement> assignment, ExamPlacement value, Set<ExamPlacement> conflicts) { 114 Exam exam = value.variable(); 115 if (getBackToBackDistance() < 0) return 0; 116 int penalty = 0; 117 ExamPeriod period = value.getPeriod(); 118 Map<ExamStudent, Set<Exam>> prev = (period.prev() != null && period.prev().getDay() == period.getDay() ? ((ExamModel)getModel()).getStudentsOfPeriod(assignment, period.prev()) : null); 119 Map<ExamStudent, Set<Exam>> next = (period.next() != null && period.next().getDay() == period.getDay() ? ((ExamModel)getModel()).getStudentsOfPeriod(assignment, period.next()) : null); 120 for (ExamStudent s : exam.getStudents()) { 121 if (prev != null) { 122 Set<Exam> exams = prev.get(s); 123 if (exams != null) 124 for (Exam x : exams) { 125 if (x.equals(exam)) 126 continue; 127 if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance()) 128 penalty++; 129 } 130 } 131 if (next != null) { 132 Set<Exam> exams = next.get(s); 133 if (exams != null) 134 for (Exam x : exams) { 135 if (x.equals(exam)) 136 continue; 137 if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance()) 138 penalty++; 139 } 140 } 141 } 142 /* 143 for (ExamStudent s : exam.getStudents()) { 144 if (period.prev() != null) { 145 if (period.prev().getDay() == period.getDay()) { 146 for (Exam x : s.getExams(assignment, period.prev())) { 147 if (x.equals(exam)) 148 continue; 149 if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance()) 150 penalty++; 151 } 152 } 153 } 154 if (period.next() != null) { 155 if (period.next().getDay() == period.getDay()) { 156 for (Exam x : s.getExams(assignment, period.next())) { 157 if (x.equals(exam)) 158 continue; 159 if (value.getDistanceInMeters(assignment.getValue(x)) > getBackToBackDistance()) 160 penalty++; 161 } 162 } 163 } 164 } 165 */ 166 return penalty; 167 } 168 169 @Override 170 public String getName() { 171 return "Distance Back-To-Back Conflicts"; 172 } 173 174 @Override 175 public void getInfo(Assignment<Exam, ExamPlacement> assignment, Map<String, String> info) { 176 if (getBackToBackDistance() >= 0.0 && getValue(assignment) != 0.0) 177 info.put(getName(), sDoubleFormat.format(getValue(assignment))); 178 } 179 180 @Override 181 public String toString(Assignment<Exam, ExamPlacement> assignment) { 182 return (getValue(assignment) <= 0.0 ? "" : "BTBd:" + sDoubleFormat.format(getValue(assignment))); 183 } 184 185 @Override 186 public boolean isPeriodCriterion() { return false; } 187}