Package org.opt4j.operator.diversity

Class DiversityPermutation

java.lang.Object

org.opt4j.operator.diversity.DiversityPermutation

All Implemented Interfaces:

Operator<PermutationGenotype<?>>, Diversity<PermutationGenotype<?>>

public class DiversityPermutation
extends Object
implements Diversity<PermutationGenotype<?>>

The DiversityPermutation is the interface for Diversity operators for PermutationGenotypes.

Given are n elements e in E two permutations p1, p2 of these elements. The function p(e) returns the position of the element e in the permutation p. This operator calculates the following value:

        diversity(p1,p2)=sum[e in E] |p1(e)-p2(e)|/(n^2/2)
 

This value is bounded by 0 and 1 since

        min { sum[e in E] |p1(e)-p2(e)| } = 0
 

and

        max { sum[e in E] |p1(e)-p2(e)| } =
                = 2 * sum[i=1 to n/2] (n-i)-(i-1) =
                = 2 * sum[i=1 to n/2] (n-2i+1) =
                = 2 * ( n^2/2 + n/2 - n/2(n/2+1)) =
                = 2 * ( n^2/2 + n/2 - n^2/4 - n/2) =
                = n^2/2
 

.

Constructor Summary

Constructors

Constructor	Description
DiversityPermutation()

Method Summary

Modifier and Type	Method	Description
double	diversity(PermutationGenotype<?> a, PermutationGenotype<?> b)	Returns the genetic diversity of two Genotypes.

Methods inherited from class java.lang.Object

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

Constructor Detail

DiversityPermutation

public DiversityPermutation()

Method Detail

diversity

public double diversity(PermutationGenotype<?> a,
                        PermutationGenotype<?> b)

Description copied from interface: Diversity

Returns the genetic diversity of two Genotypes.

Specified by:

diversity in interface Diversity<PermutationGenotype<?>>

Parameters:

a - the first genotype

b - the second genotype

Returns:

the diversity of two genotypes