Examples with ExamPlacement org.cpsolver.exam.model.ExamPlacement used on opensource projects

Example 11 with ExamPlacement

use of org.cpsolver.exam.model.ExamPlacement in project cpsolver by UniTime.

the class ExamSimulatedAnnealing method accept.

/**
     * True if the given neighboir is to be be accepted
     * 
     * @param solution
     *            current solution
     * @param neighbour
     *            proposed move
     * @return true if generated random number is below
     *         {@link ExamSimulatedAnnealing.Context#prob(double)}
     */
protected boolean accept(Solution<Exam, ExamPlacement> solution, Neighbour<Exam, ExamPlacement> neighbour) {
    if (neighbour instanceof LazyNeighbour) {
        ((LazyNeighbour<Exam, ExamPlacement>) neighbour).setAcceptanceCriterion(this);
        return true;
    }
    Assignment<Exam, ExamPlacement> assignment = solution.getAssignment();
    double value = (iRelativeAcceptance ? neighbour.value(assignment) : solution.getModel().getTotalValue(assignment) + neighbour.value(assignment) - solution.getBestValue());
    Context context = getContext(solution.getAssignment());
    double prob = context.prob(value);
    if (prob >= 1.0 || ToolBox.random() < prob) {
        context.accepted(neighbour.value(assignment));
        return true;
    }
    return false;
}

Example 12 with ExamPlacement

use of org.cpsolver.exam.model.ExamPlacement in project cpsolver by UniTime.

the class ExamSplitter method shuffle.

/**
     * Shuffle students between the given exam and all the other exams in the split (if there are any).
     * Only moves between exams that improve {@link ExamSplitter#delta(Assignment, ExamStudent, ExamPlacement, ExamPlacement)} are
     * considered.
     * @param assignment current assignment
     * @param exam an exam in question
     * @param iteration solver iteration
     */
public void shuffle(Assignment<Exam, ExamPlacement> assignment, Exam exam, long iteration) {
    // Parent exam (its either the exam itself, or its parent if it has been already split)
    Exam parent = (iParent.containsKey(exam) ? iParent.get(exam) : exam);
    // Its children (if already split)
    List<Exam> children = iChildren.get(parent);
    if (children != null && !children.isEmpty()) {
        // Unassign all involved exams
        Map<Exam, ExamPlacement> assignments = new HashMap<Exam, ExamPlacement>();
        if (assignment.getValue(parent) != null) {
            assignments.put(parent, assignment.getValue(parent));
            assignment.unassign(iteration, parent);
        }
        for (Exam child : children) {
            if (assignment.getValue(child) != null) {
                assignments.put(child, assignment.getValue(child));
                assignment.unassign(iteration, child);
            }
        }
        // Move away from parent
        for (ExamStudent student : new ArrayList<ExamStudent>(parent.getStudents())) {
            Exam child = null;
            double delta = 0;
            for (Exam x : children) {
                double d = delta(assignment, student, assignments.get(parent), assignments.get(x));
                if (child == null || d < delta) {
                    delta = d;
                    child = x;
                }
            }
            if (child != null && delta < 0) {
                student.removeVariable(parent);
                student.addVariable(child);
            }
        }
        // Move students away from a child
        for (Exam child : children) {
            for (ExamStudent student : new ArrayList<ExamStudent>(child.getStudents())) {
                Exam other = parent;
                double delta = delta(assignment, student, assignments.get(child), assignments.get(parent));
                for (Exam x : children) {
                    if (x.equals(child))
                        continue;
                    double d = delta(assignment, student, assignments.get(child), assignments.get(x));
                    if (d < delta) {
                        delta = d;
                        other = x;
                    }
                }
                if (other != null && delta < 0) {
                    student.removeVariable(child);
                    student.addVariable(other);
                }
            }
        }
        // Assign everything back
        ExamPlacement parentPlacement = assignments.get(parent);
        if (parentPlacement != null)
            assignment.assign(iteration, parentPlacement);
        for (Exam child : children) {
            ExamPlacement placement = assignments.get(child);
            if (placement != null)
                assignment.assign(iteration, placement);
        }
    }
}

Example 13 with ExamPlacement

use of org.cpsolver.exam.model.ExamPlacement in project cpsolver by UniTime.

the class ExamSplitter method bestSaved.

/** Best solution was saved, remember the current splits */
@Override
public void bestSaved(Assignment<Exam, ExamPlacement> assignment) {
    super.bestSaved(assignment);
    if (iBestSplit == null)
        iBestSplit = new Hashtable<Exam, List<ExamPlacement>>();
    else
        iBestSplit.clear();
    for (Map.Entry<Exam, List<Exam>> entry : iChildren.entrySet()) {
        Exam parent = entry.getKey();
        List<ExamPlacement> placements = new ArrayList<ExamPlacement>();
        for (Exam child : entry.getValue()) {
            if (assignment.getValue(child) != null)
                placements.add(assignment.getValue(child));
        }
        if (!placements.isEmpty())
            iBestSplit.put(parent, placements);
    }
}

Example 14 with ExamPlacement

use of org.cpsolver.exam.model.ExamPlacement in project cpsolver by UniTime.

the class ExamSplitter method merge.

/**
     * Merge an exam
     * @param assignment current assignment
     * @param child an exam to be merged
     * @param iteration solver iteration
     * @return parent exam of the exam that has been deleted; null if the given exam cannot be merged
     */
public Exam merge(Assignment<Exam, ExamPlacement> assignment, Exam child, long iteration) {
    if (!canMerge(child))
        return null;
    // Update the parent and children structures
    Exam parent = iParent.get(child);
    iParent.remove(child);
    List<Exam> children = iChildren.get(parent);
    children.remove(child);
    iValue -= 1.0;
    // Unassign parent and the given exam
    ExamPlacement parentPlacement = assignment.getValue(parent);
    if (parentPlacement != null)
        assignment.unassign(iteration, parent);
    if (assignment.getValue(child) != null)
        assignment.unassign(iteration, child);
    // Move students back from the given exam
    for (ExamStudent student : new ArrayList<ExamStudent>(child.getStudents())) {
        student.removeVariable(child);
        student.addVariable(parent);
    }
    // Remove the given exam from the model
    for (ExamRoomPlacement room : child.getRoomPlacements()) room.getRoom().removeVariable(child);
    parent.getModel().removeVariable(child);
    // Assign parent exam back
    if (parentPlacement != null)
        assignment.assign(iteration, parentPlacement);
    // Shuffle students between parent exam and its remaining children
    shuffle(assignment, parent, iteration);
    // Return parent exam
    return parent;
}

Example 15 with ExamPlacement

use of org.cpsolver.exam.model.ExamPlacement in project cpsolver by UniTime.

the class ExamSplitter method split.

/**
     * Split an exam
     * @param assignment current assignment
     * @param parent an exam to be split
     * @param iteration solver iteration
     * @param placement placement of the new exam
     * @return new exam assigned to the given placement with students moved into it; null if the given exam cannot be split
     */
public Exam split(Assignment<Exam, ExamPlacement> assignment, Exam parent, long iteration, ExamPlacement placement) {
    if (!canSplit(parent))
        return null;
    // Create the child exam
    Exam child = new Exam(--iLastSplitId, parent.getName(), parent.getLength(), parent.hasAltSeating(), parent.getMaxRooms(), parent.getMinSize(), parent.getPeriodPlacements(), parent.getRoomPlacements());
    child.setSizeOverride(parent.getSizeOverride());
    child.setPrintOffset(parent.getPrintOffset());
    child.setAveragePeriod(parent.getAveragePeriod());
    child.getOwners().addAll(parent.getOwners());
    // Update the parent and children structures
    iParent.put(child, parent);
    List<Exam> children = iChildren.get(parent);
    if (children == null) {
        children = new ArrayList<Exam>();
        iChildren.put(parent, children);
    }
    children.add(child);
    iValue += 1.0;
    // Add into model
    parent.getModel().addVariable(child);
    for (ExamRoomPlacement room : child.getRoomPlacements()) room.getRoom().addVariable(child);
    if (placement != null)
        assignment.assign(iteration, new ExamPlacement(child, placement.getPeriodPlacement(), placement.getRoomPlacements()));
    // Shuffle students between parent exam and its children
    shuffle(assignment, parent, iteration);
    // Return the new exam
    return child;
}