001 package net.sf.cpsolver.studentsct.heuristics.selection;
002
003 import org.apache.log4j.Logger;
004
005 import net.sf.cpsolver.ifs.model.Neighbour;
006 import net.sf.cpsolver.ifs.solution.Solution;
007 import net.sf.cpsolver.ifs.solver.Solver;
008 import net.sf.cpsolver.ifs.util.DataProperties;
009 import net.sf.cpsolver.ifs.util.Progress;
010 import net.sf.cpsolver.studentsct.heuristics.studentord.StudentOrder;
011 import net.sf.cpsolver.studentsct.heuristics.studentord.StudentRandomOrder;
012 import net.sf.cpsolver.studentsct.model.Student;
013
014 /**
015 * Resection incomplete studends.
016 * An extension of {@link BranchBoundSelection}, where only students that are
017 * not complete ({@link Student#isComplete()} is false) and that are sectioned
018 * somewhere ({@link Student#nrAssignedRequests()} is greater then zero) are
019 * resectioned.
020 *
021 * <br><br>
022 *
023 * @version
024 * StudentSct 1.1 (Student Sectioning)<br>
025 * Copyright (C) 2007 Tomáš Müller<br>
026 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
027 * Lazenska 391, 76314 Zlin, Czech Republic<br>
028 * <br>
029 * This library is free software; you can redistribute it and/or
030 * modify it under the terms of the GNU Lesser General Public
031 * License as published by the Free Software Foundation; either
032 * version 2.1 of the License, or (at your option) any later version.
033 * <br><br>
034 * This library is distributed in the hope that it will be useful,
035 * but 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.
038 * <br><br>
039 * You should have received a copy of the GNU Lesser General Public
040 * License along with this library; if not, write to the Free Software
041 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
042 */
043
044 public class ResectionIncompleteStudentsSelection extends BranchBoundSelection {
045 private static Logger sLog = Logger.getLogger(ResectionIncompleteStudentsSelection.class);
046
047 public ResectionIncompleteStudentsSelection(DataProperties properties) {
048 super(properties);
049 iOrder = new StudentRandomOrder(properties);
050 if (properties.getProperty("Neighbour.ResectionIncompleteStudentsOrder")!=null) {
051 try {
052 iOrder = (StudentOrder)Class.forName(properties.getProperty("Neighbour.ResectionIncompleteStudentsOrder")).
053 getConstructor(new Class[] {DataProperties.class}).
054 newInstance(new Object[] {properties});
055 } catch (Exception e) {
056 sLog.error("Unable to set student order, reason:"+e.getMessage(),e);
057 }
058 }
059 }
060
061 public void init(Solver solver) {
062 init(solver, "Resection incomplete students...");
063 }
064
065
066 /**
067 * Select neighbour. All students with an incomplete and non-empty schedule are taken,
068 * one by one in a random order. For each student a branch & bound search is employed.
069 */
070 public Neighbour selectNeighbour(Solution solution) {
071 while (iStudentsEnumeration.hasMoreElements()) {
072 Student student = (Student)iStudentsEnumeration.nextElement();
073 Progress.getInstance(solution.getModel()).incProgress();
074 if (student.nrAssignedRequests()==0 || student.isComplete()) continue;
075 Neighbour neighbour = getSelection(student).select();
076 if (neighbour!=null) return neighbour;
077 }
078 return null;
079 }
080
081 }