    001package org.cpsolver.studentsct.online.expectations;
    002
    003import org.cpsolver.ifs.assignment.Assignment;
    004import org.cpsolver.ifs.util.DataProperties;
    005import org.cpsolver.studentsct.model.Enrollment;
    006import org.cpsolver.studentsct.model.Request;
    007import org.cpsolver.studentsct.model.Section;
    008import org.cpsolver.studentsct.model.Subpart;
    009
    010/**
    011 * Avoid unbalanced sections when there are no expectations. When there are
    012 * expectations, the {@link PercentageOverExpected} is used. If there are no
    013 * expectations, sections that would have more students than given by the balance
    014 * are marked as over-expected. The target fill ratio is proportional to the section
    015 * size, a section is considered unbalanced, when the target fill is exceeded by
    016 * more than OverExpected.Disbalance percentage (defaults to 0.1). Unlimited
    017 * sections are also balanced, when General.BalanceUnlimited parameter is set
    018 * to true (defaults to false).<br><br>
    019 * A class of an offering with no expectations is over-expected when the number
    020 * of enrolled students (including the student in question) minus the target
    021 * fill is over the OverExpected.Disbalance portion of the section limit.
    022 *
    023 * @author  Tomáš Müller
    024 * @version StudentSct 1.3 (Student Sectioning)<br>
    025 *          Copyright (C) 2014 Tomáš Müller<br>
    026 *          <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
    027 *          <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
    028 * <br>
    029 *          This library is free software; you can redistribute it and/or modify
    030 *          it under the terms of the GNU Lesser General Public License as
    031 *          published by the Free Software Foundation; either version 3 of the
    032 *          License, or (at your option) any later version. <br>
    033 * <br>
    034 *          This library is distributed in the hope that it will be useful, but
    035 *          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. <br>
    038 * <br>
    039 *          You should have received a copy of the GNU Lesser General Public
    040 *          License along with this library; if not see <a
    041 *          href='http://www.gnu.org/licenses'>http://www.gnu.org/licenses</a>.
    042 *
    043 */
    044public class AvoidUnbalancedWhenNoExpectations extends PercentageOverExpected {
    045    private Double iDisbalance = 0.1;
    046    private boolean iBalanceUnlimited = false;
    047
    048    public AvoidUnbalancedWhenNoExpectations(DataProperties config) {
    049        super(config);
    050        iDisbalance = config.getPropertyDouble("OverExpected.Disbalance", iDisbalance);
    051        iBalanceUnlimited = config.getPropertyBoolean("General.BalanceUnlimited", iBalanceUnlimited);
    052    }
    053
    054    public AvoidUnbalancedWhenNoExpectations(Double percentage, Double disbalance) {
    055        super(percentage);
    056        iDisbalance = disbalance;
    057    }
    058
    059    public AvoidUnbalancedWhenNoExpectations(Double percentage) {
    060        this(percentage, null);
    061    }
    062
    063    public AvoidUnbalancedWhenNoExpectations() {
    064        this(null, null);
    065    }
    066
    067    /**
    068     * Return allowed disbalance, defaults to 0.1 (parameter OverExpected.Disbalance)
    069     * @return allowed disbalance
    070     */
    071    public Double getDisbalance() {
    072        return iDisbalance;
    073    }
    074
    075    /**
    076     * Is balancing of unlimited sections enabled (parameter General.BalanceUnlimited)
    077     * @return true if balancing of unlimited sections is enabled
    078     */
    079    public boolean isBalanceUnlimited() {
    080        return iBalanceUnlimited;
    081    }
    082
    083    @Override
    084    public double getOverExpected(Assignment<Request, Enrollment> assignment, Section section, Request request) {
    085        Subpart subpart = section.getSubpart();
    086
    087        if (hasExpectations(subpart) && section.getLimit() > 0)
    088            return super.getOverExpected(assignment, section, request);
    089
    090        if (getDisbalance() == null || getDisbalance() < 0.0)
    091            return 0.0;
    092
    093        double enrlConfig = request.getWeight() + getEnrollment(assignment, subpart.getConfig(), request);
    094        int subparts = section.getSubpart().getConfig().getSubparts().size();
    095        int limit = getLimit(section);
    096        double enrl = request.getWeight() + getEnrollment(assignment, section, request);
    097
    098        if (limit > 0) {
    099            // sections have limits -> desired size is section limit x (total
    100            // enrollment / total limit)
    101            double desired = (enrlConfig / getLimit(subpart)) * limit;
    102            if (enrl - desired >= Math.max(1.0, getDisbalance() * limit))
    103                return 1.0 / subparts;
    104        } else if (isBalanceUnlimited()) {
    105            // unlimited sections -> desired size is total enrollment / number
    106            // of sections
    107            double desired = enrlConfig / subpart.getSections().size();
    108            if (enrl - desired >= Math.max(1.0, getDisbalance() * desired))
    109                return 1.0 / subparts;
    110        }
    111
    112        return 0.0;
    113    }
    114
    115    @Override
    116    public String toString() {
    117        return "bal(" + getPercentage() + "," + getDisbalance() + ")";
    118    }
    119
    120}