org.cpsolver.ifs.heuristics

Class RouletteWheelSelection<E>

java.lang.Object

org.cpsolver.ifs.heuristics.RouletteWheelSelection<E>

Type Parameters:

E - Class of objects that are to be selected from.

All Implemented Interfaces:

Enumeration<E>

public class RouletteWheelSelection<E>
extends Object
implements Enumeration<E>

A general roulette wheel selection. An object is selected randomly, proportionaly to the provided weight. This class also supports multiple selections (it implements Enumeration interface).

Version:

StudentSct 1.3 (Student Sectioning)
Copyright (C) 2007 - 2014 Tomáš Müller
muller@unitime.org
http://muller.unitime.org

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not see http://www.gnu.org/licenses/.

Author:

Tomáš Müller

Constructor Summary

Constructors

Constructor and Description
RouletteWheelSelection()

Method Summary

Modifier and Type	Method and Description
void	add(E adept, double points) Add an adept to the selection
void	addExisting(E adept, double points) Add an adept to the selection.
double	getRemainingPoints() Total value of objects that are still in the selection.
double	getTotalPoints() Total value of objects that were added into the selection.
double	getUsedPoints() Total value of objects that were already returned by the selection.
boolean	hasMoreElements() Are there still some adepts that have not been yet selected
E	nextElement() Perform selection.
int	size() Number of objects in the set

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RouletteWheelSelection

public RouletteWheelSelection()

Method Detail

add

public void add(E adept,
                double points)

Add an adept to the selection

Parameters:

adept - an object

points - object weight (more points, better chance to be selected)

addExisting

public void addExisting(E adept,
                        double points)

Add an adept to the selection. Only increase points when the adept already exist in the selection.

Parameters:

adept - an object

points - object weight (more points, better chance to be selected)

hasMoreElements

public boolean hasMoreElements()

Are there still some adepts that have not been yet selected

Specified by:

hasMoreElements in interface Enumeration<E>

nextElement

public E nextElement()

Perform selection. An object is selected randomly with the probability proportional to the provided weight. Each object can be selected only once.

Specified by:

nextElement in interface Enumeration<E>

size

public int size()

Number of objects in the set

Returns:

number of objects in the set

getUsedPoints

public double getUsedPoints()

Total value of objects that were already returned by the selection.

Returns:

total value of objects that were already returned by the selection

getRemainingPoints

public double getRemainingPoints()

Total value of objects that are still in the selection.

Returns:

total value of objects that are still in the selection

getTotalPoints

public double getTotalPoints()

Total value of objects that were added into the selection.

Returns:

total value of objects that were added into the selection