org.hu.hom.api.algorithm.object.impl.selection

Class RouletteWheelSelection

java.lang.Object

org.hu.hom.api.algorithm.object.impl.selection.RouletteWheelSelection

All Implemented Interfaces:

SelectionStrategy<HigherOrderMutant>

public class RouletteWheelSelection
extends java.lang.Object
implements SelectionStrategy<HigherOrderMutant>

Implements selection of n candidates from a population by selecting n candidates at random where the probability of each candidate getting selected is proportional to its fitness score. This is analogous to each candidate being assigned an area on a roulette wheel proportionate to its fitness and the wheel being spun i times. Candidates may be selected more than once.

In some instances, particularly with small population sizes, the randomness of selection may result in excessively high occurrences of particular candidates.

Author:

Daniel Dyer, Asendar

Constructor Summary

Constructors

Constructor and Description
RouletteWheelSelection()

Method Summary

Modifier and Type	Method and Description
java.util.List<HigherOrderMutant>	select(Population<HigherOrderMutant> population, int selectionSize) Select the specified number of candidates from the population.

Methods inherited from class java.lang.Object

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

Constructor Detail

RouletteWheelSelection

public RouletteWheelSelection()

Method Detail

select

public java.util.List<HigherOrderMutant> select(Population<HigherOrderMutant> population,
                                                int selectionSize)

Description copied from interface: SelectionStrategy

Select the specified number of candidates from the population. Implementations may assume that the population is sorted in descending order according to fitness (so the fittest individual is the first item in the list).

It is an error to call this method with an empty or null population.

Specified by:

select in interface SelectionStrategy<HigherOrderMutant>

Parameters:

population - The Population from which to select.

selectionSize - The number of individual selections to make.

Returns:

A list containing the selected candidates.