001 package net.sf.cpsolver.ifs.example.rpp;
002
003 import net.sf.cpsolver.ifs.model.Model;
004
005 /**
006 * RPP model. <br>
007 * <br>
008 * The random placement problem (RPP; for more details, see <a href=
009 * 'http://www.fi.muni.cz/~hanka/rpp/'>http://www.fi.muni.cz/~hanka/rpp/</a>)
010 * seeks to place a set of randomly generated rectangles (called objects) of
011 * different sizes into a larger rectangle (called placement area) in such a way
012 * that no objects overlap and all objects� borders are parallel to the border
013 * of the placement area. In addition, a set of allowable placements can be
014 * randomly generated for each object. The ratio between the total area of all
015 * objects and the size of the placement area will be denoted as the filled area
016 * ratio. <br>
017 * <br>
018 * RPP allows us to generate various instances of the problem similar to a
019 * trivial timetabling problem. The correspondence is as follows: the object
020 * corresponds to a course to be timetabled � the x-coordinate to its time, the
021 * y-coordinate to its classroom. For example, a course taking three hours
022 * corresponds to an object with dimensions 3x1 (the course should be taught in
023 * one classroom only). Each course can be placed only in a classroom of
024 * sufficient capacity � we can expect that the classrooms are ordered
025 * increasingly in their size so each object will have a lower bound on its
026 * y-coordinate.
027 *
028 * @version IFS 1.2 (Iterative Forward Search)<br>
029 * Copyright (C) 2006 - 2010 Tomas Muller<br>
030 * <a href="mailto:muller@unitime.org">muller@unitime.org</a><br>
031 * <a href="http://muller.unitime.org">http://muller.unitime.org</a><br>
032 * <br>
033 * This library is free software; you can redistribute it and/or modify
034 * it under the terms of the GNU Lesser General Public License as
035 * published by the Free Software Foundation; either version 3 of the
036 * License, or (at your option) any later version. <br>
037 * <br>
038 * This library is distributed in the hope that it will be useful, but
039 * WITHOUT ANY WARRANTY; without even the implied warranty of
040 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
041 * Lesser General Public License for more details. <br>
042 * <br>
043 * You should have received a copy of the GNU Lesser General Public
044 * License along with this library; if not see
045 * <a href='http://www.gnu.org/licenses/'>http://www.gnu.org/licenses/</a>.
046 */
047 public class RPPModel extends Model<Rectangle, Location> {
048 /** Constructor. */
049 public RPPModel() {
050 super();
051 }
052
053 /** Returns rectangle of the given name */
054 public Rectangle getRectangle(String name) {
055 for (Rectangle r : variables()) {
056 if (name.equals(r.getName()))
057 return r;
058 }
059 return null;
060 }
061
062 }