    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 FractionallyOverExpected} is used. If there are no
    013 * expectations, sections that would have more students than given by the
    014 * balance are marked as over-expected. The target fill ratio is proportional to
    015 * the section size, a section is considered unbalanced, when the target fill is
    016 * exceeded by more than OverExpected.Disbalance percentage (defaults to 0.1).
    017 * Unlimited sections are also balanced, when General.BalanceUnlimited parameter
    018 * is set to true (defaults to false).<br>
    019 * <br>
    020 * A class of an offering with no expectations is over-expected when the number
    021 * of enrolled students (including the student in question) minus the target
    022 * fill is over the OverExpected.Disbalance portion of the section limit.
    023 *
    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 FractionallyUnbalancedWhenNoExpectations extends FractionallyOverExpected {
    045    private Double iDisbalance = 0.1;
    046    private boolean iBalanceUnlimited = false;
    047
    048    public FractionallyUnbalancedWhenNoExpectations(DataProperties config) {
    049        super(config);
    050        iDisbalance = config.getPropertyDouble("OverExpected.Disbalance", iDisbalance);
    051        iBalanceUnlimited = config.getPropertyBoolean("General.BalanceUnlimited", iBalanceUnlimited);
    052    }
    053
    054    public FractionallyUnbalancedWhenNoExpectations(Double percentage, Double maximum, Double disbalance) {
    055        super(percentage, maximum);
    056        iDisbalance = disbalance;
    057    }
    058
    059    public FractionallyUnbalancedWhenNoExpectations(Double percentage, Double maximum) {
    060        this(percentage, maximum, null);
    061    }
    062
    063    public FractionallyUnbalancedWhenNoExpectations(Double percentage) {
    064        this(percentage, null, null);
    065    }
    066
    067    public FractionallyUnbalancedWhenNoExpectations() {
    068        this(null, null, null);
    069    }
    070
    071    /**
    072     * Return allowed disbalance, defaults to 0.1 (parameter OverExpected.Disbalance)
    073     *
    074     * @return allowed disbalance
    075     */
    076    public Double getDisbalance() {
    077        return iDisbalance;
    078    }
    079
    080    /**
    081     * Is balancing of unlimited sections enabled (parameter General.BalanceUnlimited)
    082     * @return true if balancing of unlimited sections is enabled
    083     */
    084    public boolean isBalanceUnlimited() {
    085        return iBalanceUnlimited;
    086    }
    087
    088    /**
    089     * Get maximum
    090     * @param section given section
    091     * @param defaultValue default value (if not set)
    092     * @return maximum
    093     */
    094    public double getMaximum(Section section, double defaultValue) {
    095        return getMaximum() == null || getMaximum() <= 0.0 ? defaultValue : getMaximum();
    096    }
    097
    098    @Override
    099    public double getOverExpected(Assignment<Request, Enrollment> assignment, Section section, Request request) {
    100        Subpart subpart = section.getSubpart();
    101
    102        if (hasExpectations(subpart) && section.getLimit() > 0)
    103            return super.getOverExpected(assignment, section, request);
    104
    105        if (getDisbalance() == null || getDisbalance() < 0.0)
    106            return 0.0;
    107
    108        double enrlConfig = request.getWeight() + getEnrollment(assignment, subpart.getConfig(), request);
    109        int subparts = section.getSubpart().getConfig().getSubparts().size();
    110        int limit = getLimit(section);
    111        double enrl = request.getWeight() + getEnrollment(assignment, section, request);
    112
    113        if (limit > 0) {
    114            // sections have limits -> desired size is section limit x (total
    115            // enrollment / total limit)
    116            double desired = (enrlConfig / getLimit(subpart)) * limit;
    117            if (enrl - desired >= Math.max(1.0, getDisbalance() * limit)) {
    118                double max = getMaximum(section, limit);
    119                return Math.min(max, enrl - desired) / (max * subparts);
    120            }
    121        } else if (isBalanceUnlimited()) {
    122            // unlimited sections -> desired size is total enrollment / number
    123            // of sections
    124            double desired = enrlConfig / subpart.getSections().size();
    125            if (enrl - desired >= Math.max(1.0, getDisbalance() * desired)) {
    126                double max = getMaximum(section, desired);
    127                return Math.min(max, enrl - desired) / (max * subparts);
    128            }
    129        }
    130
    131        return 0.0;
    132    }
    133
    134    @Override
    135    public String toString() {
    136        return "fbal(" + getPercentage() + "," + getMaximum() + "," + getDisbalance() + ")";
    137    }
    138}