001package org.cpsolver.instructor.criteria; 002 003import java.util.Collection; 004import java.util.HashSet; 005import java.util.Set; 006 007import org.cpsolver.ifs.assignment.Assignment; 008import org.cpsolver.ifs.solver.Solver; 009import org.cpsolver.ifs.util.DataProperties; 010import org.cpsolver.instructor.model.Instructor; 011import org.cpsolver.instructor.model.InstructorSchedulingModel; 012import org.cpsolver.instructor.model.TeachingAssignment; 013import org.cpsolver.instructor.model.TeachingRequest; 014 015/** 016 * Back to Back. This criterion counts how well are the back-to-back preferences that are set on an {@link Instructor} met 017 * (counting {@link Instructor#countBackToBacks(Assignment, TeachingAssignment, double, double)}). 018 * 019 * @version IFS 1.3 (Instructor Sectioning)<br> 020 * Copyright (C) 2016 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 */ 038public class BackToBack extends InstructorSchedulingCriterion { 039 private double iDiffRoomWeight = 0.8, iDiffTypeWeight = 0.5; 040 041 public BackToBack() { 042 setValueUpdateType(ValueUpdateType.NoUpdate); 043 } 044 045 @Override 046 public boolean init(Solver<TeachingRequest, TeachingAssignment> solver) { 047 iDiffRoomWeight = solver.getProperties().getPropertyDouble("BackToBack.DifferentRoomWeight", 0.8); 048 iDiffTypeWeight = solver.getProperties().getPropertyDouble("BackToBack.DifferentTypeWeight", 0.5); 049 return super.init(solver); 050 } 051 052 @Override 053 public double getWeightDefault(DataProperties config) { 054 return 1.0; 055 } 056 057 /** 058 * Different room weight 059 * @return penalty for teaching two back-to-back that are in different rooms 060 */ 061 public double getDifferentRoomWeight() { return iDiffRoomWeight; } 062 063 /** 064 * Different instructional type weight 065 * @return penalty for teaching two back-to-back that are of different instructional type 066 */ 067 public double getDifferentTypeWeight() { return iDiffTypeWeight; } 068 069 @Override 070 public double getValue(Assignment<TeachingRequest, TeachingAssignment> assignment, TeachingAssignment value, Set<TeachingAssignment> conflicts) { 071 return value.getInstructor().countBackToBacks(assignment, value, iDiffRoomWeight, iDiffTypeWeight); 072 } 073 074 @Override 075 protected double[] computeBounds(Assignment<TeachingRequest, TeachingAssignment> assignment) { 076 double[] bounds = new double[] { 0.0, 0.0 }; 077 for (Instructor instructor: ((InstructorSchedulingModel)getModel()).getInstructors()) { 078 bounds[1] += Math.abs(instructor.getBackToBackPreference()); 079 } 080 return bounds; 081 } 082 083 @Override 084 public double[] getBounds(Assignment<TeachingRequest, TeachingAssignment> assignment, Collection<TeachingRequest> variables) { 085 double[] bounds = new double[] { 0.0, 0.0 }; 086 for (Instructor instructor: getInstructors(assignment, variables)) { 087 bounds[1] += Math.abs(instructor.getBackToBackPreference()); 088 } 089 return bounds; 090 } 091 092 @Override 093 public double getValue(Assignment<TeachingRequest, TeachingAssignment> assignment, Collection<TeachingRequest> variables) { 094 double value = 0.0; 095 Set<Instructor> instructors = new HashSet<Instructor>(); 096 for (Instructor instructor: ((InstructorSchedulingModel)getModel()).getInstructors()) { 097 if (instructors.add(instructor)) { 098 value += instructor.getContext(assignment).countBackToBackPreference(iDiffRoomWeight, iDiffTypeWeight); 099 } 100 } 101 return value; 102 } 103 104 @Override 105 public String getAbbreviation() { 106 return "Back2Back"; 107 } 108}