Examples with SimpleNeighbour org.cpsolver.ifs.model.SimpleNeighbour used on opensource projects

Example 1 with SimpleNeighbour

use of org.cpsolver.ifs.model.SimpleNeighbour in project cpsolver by UniTime.

the class RandomSwapMove method selectNeighbour.

@Override
public Neighbour<V, T> selectNeighbour(Solution<V, T> solution) {
    Model<V, T> model = solution.getModel();
    Assignment<V, T> assignment = solution.getAssignment();
    double total = model.getTotalValue(assignment);
    int varIdx = ToolBox.random(model.variables().size());
    for (int i = 0; i < model.variables().size(); i++) {
        V variable = model.variables().get((i + varIdx) % model.variables().size());
        List<T> values = variable.values(solution.getAssignment());
        if (values.isEmpty())
            continue;
        int valIdx = ToolBox.random(values.size());
        T old = variable.getAssignment(assignment);
        Lock lock = solution.getLock().writeLock();
        lock.lock();
        try {
            int attempts = 0;
            long startTime = JProf.currentTimeMillis();
            for (int j = 0; j < values.size(); j++) {
                T value = values.get((j + valIdx) % values.size());
                if (value.equals(old))
                    continue;
                Set<T> conflicts = model.conflictValues(assignment, value);
                if (conflicts.contains(value))
                    continue;
                if (conflicts.isEmpty()) {
                    SimpleNeighbour<V, T> n = new SimpleNeighbour<V, T>(variable, value);
                    if (!iHC || n.value(assignment) <= 0)
                        return n;
                    else
                        continue;
                }
                Map<V, T> assignments = new HashMap<V, T>();
                assignments.put(variable, value);
                for (T conflict : conflicts) assignment.unassign(solution.getIteration(), conflict.variable());
                assignment.assign(solution.getIteration(), value);
                Double v = resolve(solution, total, startTime, assignments, new ArrayList<T>(conflicts), 0);
                if (!conflicts.isEmpty())
                    attempts++;
                assignment.unassign(solution.getIteration(), variable);
                for (T conflict : conflicts) assignment.assign(solution.getIteration(), conflict);
                if (old != null)
                    assignment.assign(solution.getIteration(), old);
                if (v != null)
                    return new SwapNeighbour(assignments.values(), v);
                if (attempts >= iMaxAttempts)
                    break;
            }
        } finally {
            lock.unlock();
        }
    }
    return null;
}

Example 2 with SimpleNeighbour

use of org.cpsolver.ifs.model.SimpleNeighbour in project cpsolver by UniTime.

the class ExamTabuSearch method selectNeighbour.

/**
     * Neighbor selection
     */
@Override
public Neighbour<Exam, ExamPlacement> selectNeighbour(Solution<Exam, ExamPlacement> solution) {
    if (iFirstIteration < 0)
        iFirstIteration = solution.getIteration();
    TabuList tabu = getContext(solution.getAssignment());
    long idle = solution.getIteration() - Math.max(iFirstIteration, solution.getBestIteration());
    if (idle > iMaxIdleIterations) {
        sLog.debug("  [tabu]    max idle iterations reached");
        iFirstIteration = -1;
        if (tabu.size() > 0)
            tabu.clear();
        return null;
    }
    if (tabu.size() > 0 && iTabuMaxSize > iTabuMinSize) {
        if (idle == 0) {
            tabu.resize(iTabuMinSize);
        } else if (idle % (iMaxIdleIterations / (iTabuMaxSize - iTabuMinSize)) == 0) {
            tabu.resize(Math.min(iTabuMaxSize, tabu.size() + 1));
        }
    }
    boolean acceptConflicts = solution.getModel().getBestUnassignedVariables() > 0;
    ExamModel model = (ExamModel) solution.getModel();
    Assignment<Exam, ExamPlacement> assignment = solution.getAssignment();
    double bestEval = 0.0;
    List<ExamPlacement> best = null;
    for (Exam exam : model.variables()) {
        ExamPlacement assigned = assignment.getValue(exam);
        double assignedVal = (assigned == null ? iConflictWeight : iValueWeight * assigned.toDouble(assignment));
        for (ExamPeriodPlacement period : exam.getPeriodPlacements()) {
            Set<ExamRoomPlacement> rooms = exam.findBestAvailableRooms(assignment, period);
            if (rooms == null)
                rooms = exam.findRoomsRandom(assignment, period, false);
            if (rooms == null)
                continue;
            ExamPlacement value = new ExamPlacement(exam, period, rooms);
            if (value.equals(assigned))
                continue;
            double eval = iValueWeight * value.toDouble(assignment) - assignedVal;
            if (acceptConflicts) {
                Set<ExamPlacement> conflicts = model.conflictValues(assignment, value);
                for (ExamPlacement conflict : conflicts) {
                    eval -= iValueWeight * conflict.toDouble(assignment);
                    eval += iConflictWeight * (1.0 + (iStat == null ? 0.0 : iStat.countRemovals(solution.getIteration(), conflict, value)));
                }
            } else {
                if (model.inConflict(assignment, value))
                    continue;
            }
            if (tabu.size() > 0 && tabu.contains(exam.getId() + ":" + value.getPeriod().getIndex())) {
                int un = model.variables().size() - assignment.nrAssignedVariables() - (assigned == null ? 0 : 1);
                if (un > model.getBestUnassignedVariables())
                    continue;
                if (un == model.getBestUnassignedVariables() && model.getTotalValue(assignment) + eval >= solution.getBestValue())
                    continue;
            }
            if (best == null || bestEval > eval) {
                if (best == null)
                    best = new ArrayList<ExamPlacement>();
                else
                    best.clear();
                best.add(value);
                bestEval = eval;
            } else if (bestEval == eval) {
                best.add(value);
            }
        }
    }
    if (best == null) {
        sLog.debug("  [tabu] --none--");
        iFirstIteration = -1;
        if (tabu.size() > 0)
            tabu.clear();
        return null;
    }
    ExamPlacement bestVal = ToolBox.random(best);
    if (sLog.isDebugEnabled()) {
        Set<ExamPlacement> conflicts = model.conflictValues(assignment, bestVal);
        double wconf = (iStat == null ? 0.0 : iStat.countRemovals(solution.getIteration(), conflicts, bestVal));
        sLog.debug("  [tabu] " + bestVal + " (" + (assignment.getValue(bestVal.variable()) == null ? "" : "was=" + assignment.getValue(bestVal.variable()) + ", ") + "val=" + bestEval + (conflicts.isEmpty() ? "" : ", conf=" + (wconf + conflicts.size()) + "/" + conflicts) + ")");
    }
    if (tabu.size() > 0)
        tabu.add(bestVal.variable().getId() + ":" + bestVal.getPeriod().getIndex());
    return new SimpleNeighbour<Exam, ExamPlacement>(bestVal.variable(), bestVal);
}

Example 3 with SimpleNeighbour

use of org.cpsolver.ifs.model.SimpleNeighbour in project cpsolver by UniTime.

the class RoomSwap method selectNeighbour.

@Override
public Neighbour<Lecture, Placement> selectNeighbour(Solution<Lecture, Placement> solution) {
    TimetableModel model = (TimetableModel) solution.getModel();
    Assignment<Lecture, Placement> assignment = solution.getAssignment();
    double total = model.getTotalValue(assignment);
    int varIdx = ToolBox.random(model.variables().size());
    for (int i = 0; i < model.variables().size(); i++) {
        Lecture lecture = model.variables().get((i + varIdx) % model.variables().size());
        Placement old = assignment.getValue(lecture);
        if (old == null || old.getNrRooms() != 1)
            continue;
        List<RoomLocation> values = lecture.roomLocations();
        if (values.isEmpty())
            continue;
        Lock lock = solution.getLock().writeLock();
        lock.lock();
        try {
            int attempts = 0;
            int valIdx = ToolBox.random(values.size());
            long startTime = JProf.currentTimeMillis();
            for (int j = 0; j < values.size(); j++) {
                RoomLocation room = values.get((j + valIdx) % values.size());
                if (room.getPreference() > 50)
                    continue;
                if (room.equals(old.getRoomLocation()))
                    continue;
                Placement placement = new Placement(lecture, old.getTimeLocation(), room);
                if (!placement.isValid())
                    continue;
                Set<Placement> conflicts = model.conflictValues(assignment, placement);
                if (conflicts.contains(placement))
                    continue;
                if (conflicts.isEmpty()) {
                    SimpleNeighbour<Lecture, Placement> n = new SimpleNeighbour<Lecture, Placement>(lecture, placement);
                    if (!iHC || n.value(assignment) <= 0)
                        return n;
                    else
                        continue;
                }
                Map<Lecture, Placement> assignments = new HashMap<Lecture, Placement>();
                assignments.put(lecture, placement);
                for (Placement conflict : conflicts) assignment.unassign(solution.getIteration(), conflict.variable());
                assignment.assign(solution.getIteration(), placement);
                Double v = resolve(solution, total, startTime, assignments, new ArrayList<Placement>(conflicts), 0);
                if (!conflicts.isEmpty())
                    attempts++;
                assignment.unassign(solution.getIteration(), lecture);
                for (Placement conflict : conflicts) assignment.assign(solution.getIteration(), conflict);
                assignment.assign(solution.getIteration(), old);
                if (v != null)
                    return new SwapNeighbour(assignments.values(), v);
                if (attempts >= iMaxAttempts)
                    break;
            }
        } finally {
            lock.unlock();
        }
    }
    return null;
}

Example 4 with SimpleNeighbour

use of org.cpsolver.ifs.model.SimpleNeighbour in project cpsolver by UniTime.

the class TimeSwap method selectNeighbour.

@Override
public Neighbour<Lecture, Placement> selectNeighbour(Solution<Lecture, Placement> solution) {
    TimetableModel model = (TimetableModel) solution.getModel();
    Assignment<Lecture, Placement> assignment = solution.getAssignment();
    double total = model.getTotalValue(assignment);
    int varIdx = ToolBox.random(model.variables().size());
    for (int i = 0; i < model.variables().size(); i++) {
        Lecture lecture = model.variables().get((i + varIdx) % model.variables().size());
        Placement old = lecture.getAssignment(assignment);
        if (old == null)
            continue;
        List<TimeLocation> values = lecture.timeLocations();
        if (values.isEmpty())
            continue;
        Lock lock = solution.getLock().writeLock();
        lock.lock();
        try {
            int attempts = 0;
            long startTime = JProf.currentTimeMillis();
            int valIdx = ToolBox.random(values.size());
            for (int j = 0; j < values.size(); j++) {
                TimeLocation time = values.get((j + valIdx) % values.size());
                if (time.getPreference() > 50)
                    continue;
                if (time.equals(old.getTimeLocation()))
                    continue;
                Placement placement = null;
                if (lecture.getNrRooms() == 0)
                    placement = new Placement(lecture, time, (RoomLocation) null);
                else if (lecture.getNrRooms() == 1)
                    placement = new Placement(lecture, time, old.getRoomLocation());
                else
                    placement = new Placement(lecture, time, old.getRoomLocations());
                if (!placement.isValid())
                    continue;
                Set<Placement> conflicts = model.conflictValues(assignment, placement);
                if (conflicts.contains(placement))
                    continue;
                if (conflicts.isEmpty()) {
                    SimpleNeighbour<Lecture, Placement> n = new SimpleNeighbour<Lecture, Placement>(lecture, placement);
                    if (!iHC || n.value(assignment) <= 0)
                        return n;
                    else
                        continue;
                }
                Map<Lecture, Placement> assignments = new HashMap<Lecture, Placement>();
                assignments.put(lecture, placement);
                for (Placement conflict : conflicts) assignment.unassign(solution.getIteration(), conflict.variable());
                assignment.assign(solution.getIteration(), placement);
                Double v = resolve(solution, total, startTime, assignments, new ArrayList<Placement>(conflicts), 0);
                if (!conflicts.isEmpty())
                    attempts++;
                assignment.unassign(solution.getIteration(), lecture);
                for (Placement conflict : conflicts) assignment.assign(solution.getIteration(), conflict);
                assignment.assign(solution.getIteration(), old);
                if (v != null)
                    return new SwapNeighbour(assignments.values(), v);
                if (attempts >= iMaxAttempts)
                    break;
            }
        } finally {
            lock.unlock();
        }
    }
    return null;
}

Example 5 with SimpleNeighbour

use of org.cpsolver.ifs.model.SimpleNeighbour in project cpsolver by UniTime.

the class ShuffleStudentsSelection method selectNeighbour.

@Override
public Neighbour<Request, Enrollment> selectNeighbour(Solution<Request, Enrollment> solution) {
    Shuffle shuffle = null;
    while ((shuffle = iQueue.poll()) != null) {
        Progress.getInstance(solution.getModel()).incProgress();
        // Take an item from the queue, try backtrack first
        Neighbour<Request, Enrollment> n = iBacktrack.selectNeighbour(solution, shuffle);
        if (n != null)
            return n;
        // If fails, just assign the request randomly and hope for the best
        List<Enrollment> adepts = new ArrayList<Enrollment>();
        for (Enrollment e : shuffle.getRequest().values(solution.getAssignment())) {
            if (shuffle.matchFilter(e))
                adepts.add(e);
        }
        if (!adepts.isEmpty()) {
            return new SimpleNeighbour<Request, Enrollment>(shuffle.getRequest(), ToolBox.random(adepts));
        }
    }
    return null;
}