001package net.sf.cpsolver.coursett.model; 002 003import net.sf.cpsolver.ifs.model.Constraint; 004import net.sf.cpsolver.ifs.model.ModelListener; 005import net.sf.cpsolver.ifs.solver.Solver; 006 007/** 008 * On fly student sectioning. <br> 009 * <br> 010 * In this mode, students are resectioned after each iteration, but only between 011 * classes that are affected by the iteration. This slows down the solver, but 012 * it can dramatically improve results in the case when there is more stress put 013 * on student conflicts (e.g., Woebegon College example). 014 * 015 * <br> 016 * <br> 017 * Parameters: 018 * <table border='1'> 019 * <tr> 020 * <th>Parameter</th> 021 * <th>Type</th> 022 * <th>Comment</th> 023 * </tr> 024 * <tr> 025 * <td>OnFlySectioning.Enabled</td> 026 * <td>{@link Boolean}</td> 027 * <td>Enable on fly sectioning (if enabled, students will be resectioned after 028 * each iteration)</td> 029 * </tr> 030 * <tr> 031 * <td>OnFlySectioning.Recursive</td> 032 * <td>{@link Boolean}</td> 033 * <td>Recursively resection lectures affected by a student swap</td> 034 * </tr> 035 * <tr> 036 * <td>OnFlySectioning.ConfigAsWell</td> 037 * <td>{@link Boolean}</td> 038 * <td>Resection students between configurations as well</td> 039 * </tr> 040 * </table> 041 * 042 * @version CourseTT 1.2 (University Course Timetabling)<br> 043 * Copyright (C) 2006 - 2010 Tomáš Müller<br> 044 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br> 045 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br> 046 * <br> 047 * This library is free software; you can redistribute it and/or modify 048 * it under the terms of the GNU Lesser General Public License as 049 * published by the Free Software Foundation; either version 3 of the 050 * License, or (at your option) any later version. <br> 051 * <br> 052 * This library is distributed in the hope that it will be useful, but 053 * WITHOUT ANY WARRANTY; without even the implied warranty of 054 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 055 * Lesser General Public License for more details. <br> 056 * <br> 057 * You should have received a copy of the GNU Lesser General Public 058 * License along with this library; if not see 059 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>. 060 */ 061 062public class OnFlySectioning implements ModelListener<Lecture, Placement> { 063 private TimetableModel iModel; 064 private boolean iRecursive = true; 065 private boolean iConfigAsWell = false; 066 067 /** 068 * Constructor 069 * 070 * @param model 071 * timetabling model 072 */ 073 public OnFlySectioning(TimetableModel model) { 074 iModel = model; 075 } 076 077 @Override 078 public void variableAdded(Lecture variable) { 079 } 080 081 @Override 082 public void variableRemoved(Lecture variable) { 083 } 084 085 @Override 086 public void constraintAdded(Constraint<Lecture, Placement> constraint) { 087 } 088 089 @Override 090 public void constraintRemoved(Constraint<Lecture, Placement> constraint) { 091 } 092 093 @Override 094 public void beforeAssigned(long iteration, Placement value) { 095 } 096 097 @Override 098 public void beforeUnassigned(long iteration, Placement value) { 099 } 100 101 /** 102 * {@link FinalSectioning#resection(Lecture, boolean, boolean)} is called 103 * when given iteration number is greater than zero. 104 */ 105 @Override 106 public void afterAssigned(long iteration, Placement value) { 107 if (iteration > 0) 108 iModel.getStudentSectioning().resection(value.variable(), iRecursive, iConfigAsWell); 109 } 110 111 @Override 112 public void afterUnassigned(long iteration, Placement value) { 113 } 114 115 /** 116 * Initialization 117 */ 118 @Override 119 public boolean init(Solver<Lecture, Placement> solver) { 120 iRecursive = solver.getProperties().getPropertyBoolean("OnFlySectioning.Recursive", true); 121 iConfigAsWell = solver.getProperties().getPropertyBoolean("OnFlySectioning.ConfigAsWell", false); 122 return true; 123 } 124}