    001package org.cpsolver.coursett;
    002
    003import org.cpsolver.coursett.heuristics.FixCompleteSolutionNeighbourSelection;
    004import org.cpsolver.coursett.heuristics.NeighbourSelectionWithSuggestions;
    005import org.cpsolver.coursett.model.Lecture;
    006import org.cpsolver.coursett.model.Placement;
    007import org.cpsolver.coursett.model.TimetableModel;
    008import org.cpsolver.ifs.assignment.Assignment;
    009import org.cpsolver.ifs.model.Neighbour;
    010import org.cpsolver.ifs.solution.Solution;
    011import org.cpsolver.ifs.solver.Solver;
    012import org.cpsolver.ifs.util.DataProperties;
    013import org.cpsolver.ifs.util.JProf;
    014import org.cpsolver.ifs.util.Progress;
    015
    016/**
    017 * University course timetabling solver. <br>
    018 * <br>
    019 * When a complete solution is found, it is improved by limited depth
    020 * backtracking search. This way it is ensured that the fund solution is at
    021 * least locally optimal.<br>
    022 * <br>
    023 * Deprecated: use {@link FixCompleteSolutionNeighbourSelection} instead.
    024 *
    025 * @version CourseTT 1.3 (University Course Timetabling)<br>
    026 *          Copyright (C) 2006 - 2014 Tomáš Müller<br>
    027 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    028 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    029 * <br>
    030 *          This library is free software; you can redistribute it and/or modify
    031 *          it under the terms of the GNU Lesser General Public License as
    032 *          published by the Free Software Foundation; either version 3 of the
    033 *          License, or (at your option) any later version. <br>
    034 * <br>
    035 *          This library is distributed in the hope that it will be useful, but
    036 *          WITHOUT ANY WARRANTY; without even the implied warranty of
    037 *          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
    038 *          Lesser General Public License for more details. <br>
    039 * <br>
    040 *          You should have received a copy of the GNU Lesser General Public
    041 *          License along with this library; if not see
    042 *          <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
    043 */
    044
    045@Deprecated
    046public class TimetableSolver extends Solver<Lecture, Placement> {
    047    private long iLastCompleteSolutionFixIteration = -1;
    048    private long iLastIncompleteSolutionFixIteration = -1;
    049    private long iCompleteSolutionFixInterval = 1;
    050    private long iIncompleteSolutionFixInterval = 5000;
    051
    052    public TimetableSolver(DataProperties properties) {
    053        super(properties);
    054    }
    055
    056    @Override
    057    public void initSolver() {
    058        super.initSolver();
    059        iCompleteSolutionFixInterval = getProperties().getPropertyLong("General.CompleteSolutionFixInterval", iCompleteSolutionFixInterval);
    060        iIncompleteSolutionFixInterval = getProperties().getPropertyLong("General.IncompleteSolutionFixInterval", iIncompleteSolutionFixInterval);
    061    }
    062
    063    @Override
    064    protected void onAssigned(double startTime, Solution<Lecture, Placement> solution) {
    065        if (solution.getModel().nrUnassignedVariables(solution.getAssignment()) == 0) {
    066            // complete solution was found
    067            if (iCompleteSolutionFixInterval < 0) {
    068             // feature disabled
    069                return;
    070            } else if (iCompleteSolutionFixInterval == 0) {
    071                // only run first time a complete solution is found
    072                if (iLastCompleteSolutionFixIteration >= 0) return;
    073            } else {
    074                // run first time and if not run for a given number of iterations
    075                if (iLastCompleteSolutionFixIteration >= 0 && solution.getIteration() - iLastCompleteSolutionFixIteration < iCompleteSolutionFixInterval) return;
    076            }
    077            if (getSolutionComparator().isBetterThanBestSolution(solution)) {
    078                fixCompleteSolution(solution, startTime);
    079                iLastCompleteSolutionFixIteration = solution.getIteration();
    080            }
    081        } else if (solution.getBestInfo() == null) {
    082            // complete solution has not been found yet
    083            if (iIncompleteSolutionFixInterval < 0) {
    084                // feature disabled
    085                   return;
    086            } else if (iIncompleteSolutionFixInterval == 0) {
    087                // only run first time a complete solution is found
    088                if (iLastIncompleteSolutionFixIteration >= 0) return;
    089            } else {
    090                // run first time and if not run for a given number of iterations
    091                if (iLastIncompleteSolutionFixIteration >= 0 && solution.getIteration() - iLastIncompleteSolutionFixIteration < iIncompleteSolutionFixInterval) return;
    092            }
    093            if (getSolutionComparator().isBetterThanBestSolution(solution)) {
    094                fixCompleteSolution(solution, startTime);
    095                iLastIncompleteSolutionFixIteration = solution.getIteration();
    096            }
    097        }
    098    }
    099
    100    /**
    101     * Try to improve existing solution by backtracking search of very limited
    102     * depth. See {@link NeighbourSelectionWithSuggestions} for more details.
    103     * @param solution current solution
    104     * @param startTime start time
    105     */
    106    protected void fixCompleteSolution(Solution<Lecture, Placement> solution, double startTime) {
    107        Progress progress = Progress.getInstance(solution.getModel());
    108
    109        TimetableModel model = (TimetableModel) solution.getModel();
    110        Assignment<Lecture, Placement> assignment = solution.getAssignment();
    111        solution.saveBest();
    112        progress.save();
    113        double solutionValue = 0.0, newSolutionValue = model.getTotalValue(assignment);
    114        do {
    115            solutionValue = newSolutionValue;
    116            progress.setPhase("Fixing solution", model.variables().size());
    117            for (Lecture variable : model.variables()) {
    118                Placement bestValue = null;
    119                double bestVal = 0.0;
    120                Placement currentValue = assignment.getValue(variable);
    121                if (currentValue == null)
    122                    continue;
    123                double currentVal = currentValue.toDouble(assignment);
    124                for (Placement value : variable.values()) {
    125                    if (value.equals(currentValue))
    126                        continue;
    127                    if (model.conflictValues(assignment, value).isEmpty()) {
    128                        double val = value.toDouble(assignment);
    129                        if (bestValue == null || val < bestVal) {
    130                            bestValue = value;
    131                            bestVal = val;
    132                        }
    133                    }
    134                }
    135                if (bestValue != null && bestVal < currentVal)
    136                    assignment.assign(0, bestValue);
    137                solution.update(JProf.currentTimeSec() - startTime);
    138                progress.incProgress();
    139                if (iStop)
    140                    break;
    141            }
    142            newSolutionValue = model.getTotalValue(assignment);
    143            if (newSolutionValue < solutionValue) {
    144                progress.debug("New solution value is  " + newSolutionValue);
    145            }
    146        } while (!iStop && newSolutionValue < solutionValue && getTerminationCondition().canContinue(solution));
    147        progress.restore();
    148
    149        if (!solution.getModel().unassignedVariables(assignment).isEmpty())
    150            return;
    151        progress.save();
    152        try {
    153            progress.setPhase("Fixing solution [2]", model.variables().size());
    154            NeighbourSelectionWithSuggestions ns = new NeighbourSelectionWithSuggestions(this);
    155            for (Lecture lecture : model.variables()) {
    156                Neighbour<Lecture, Placement> n = ns.selectNeighbourWithSuggestions(solution, lecture, 2);
    157                if (n != null && n.value(assignment) <= 0.0)
    158                    n.assign(assignment, 0);
    159                solution.update(JProf.currentTimeSec() - startTime);
    160                progress.incProgress();
    161                if (iStop)
    162                    break;
    163            }
    164        } catch (Exception e) {
    165            sLogger.debug(e.getMessage(), e);
    166        } finally {
    167            progress.restore();
    168        }
    169    }
    170}