001package org.cpsolver.coursett.criteria; 002 003import java.util.Collection; 004import java.util.HashSet; 005import java.util.Set; 006 007import org.cpsolver.coursett.Constants; 008import org.cpsolver.coursett.constraint.InstructorConstraint; 009import org.cpsolver.coursett.model.Lecture; 010import org.cpsolver.coursett.model.Placement; 011import org.cpsolver.coursett.model.TimetableModel; 012import org.cpsolver.ifs.assignment.Assignment; 013import org.cpsolver.ifs.util.DataProperties; 014 015 016 017/** 018 * Bact-to-back instructor preferences. This criterion counts cases when an instructor 019 * has to teach two classes in two rooms that are too far a part. This objective 020 * is counter by the {@link InstructorConstraint} 021 * (see {@link InstructorConstraint#getDistancePreference(Placement, Placement)}). 022 * <br> 023 * 024 * @version CourseTT 1.3 (University Course Timetabling)<br> 025 * Copyright (C) 2006 - 2014 Tomáš Müller<br> 026 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 027 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 028 * <br> 029 * This library is free software; you can redistribute it and/or modify 030 * it under the terms of the GNU Lesser General Public License as 031 * published by the Free Software Foundation; either version 3 of the 032 * License, or (at your option) any later version. <br> 033 * <br> 034 * This library is distributed in the hope that it will be useful, but 035 * WITHOUT ANY WARRANTY; without even the implied warranty of 036 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 037 * Lesser General Public License for more details. <br> 038 * <br> 039 * You should have received a copy of the GNU Lesser General Public 040 * License along with this library; if not see 041 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>. 042 */ 043public class BackToBackInstructorPreferences extends TimetablingCriterion { 044 045 public BackToBackInstructorPreferences() { 046 setValueUpdateType(ValueUpdateType.NoUpdate); 047 } 048 049 @Override 050 public double getWeightDefault(DataProperties config) { 051 return Constants.sPreferenceLevelDiscouraged * config.getPropertyDouble("Comparator.DistanceInstructorPreferenceWeight", 1.0); 052 } 053 054 @Override 055 public String getPlacementSelectionWeightName() { 056 return "Placement.DistanceInstructorPreferenceWeight"; 057 } 058 059 protected int penalty(Assignment<Lecture, Placement> assignment, Placement value) { 060 int ret = 0; 061 for (InstructorConstraint ic: value.variable().getInstructorConstraints()) { 062 ret += ic.getPreference(assignment, value); 063 } 064 return ret; 065 } 066 067 @Override 068 public double getValue(Assignment<Lecture, Placement> assignment, Placement value, Set<Placement> conflicts) { 069 double ret = penalty(assignment, value); 070 if (conflicts != null) 071 for (Placement conflict: conflicts) 072 ret -= penalty(assignment, conflict); 073 return ret; 074 } 075 076 @Override 077 public double getValue(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) { 078 double ret = 0; 079 Set<InstructorConstraint> constraints = new HashSet<InstructorConstraint>(); 080 for (Lecture lect: variables) { 081 for (InstructorConstraint ic: lect.getInstructorConstraints()) { 082 if (!constraints.add(ic)) continue; 083 ret += ic.getPreference(assignment); 084 } 085 } 086 return ret; 087 } 088 089 @Override 090 protected double[] computeBounds(Assignment<Lecture, Placement> assignment) { 091 double[] bounds = new double[] { 0.0, 0.0 }; 092 for (InstructorConstraint ic: ((TimetableModel)getModel()).getInstructorConstraints()) 093 bounds[1] += ic.getWorstPreference(); 094 return bounds; 095 } 096 097 @Override 098 public double[] getBounds(Assignment<Lecture, Placement> assignment, Collection<Lecture> variables) { 099 double[] bounds = new double[] { 0.0, 0.0 }; 100 Set<InstructorConstraint> constraints = new HashSet<InstructorConstraint>(); 101 for (Lecture lect: variables) { 102 for (InstructorConstraint ic: lect.getInstructorConstraints()) { 103 if (!constraints.add(ic)) continue; 104 bounds[1] += ic.getWorstPreference(); 105 } 106 } 107 return bounds; 108 } 109}