Package org.cicirello.permutations.distance

Class ExactMatchDistance

java.lang.Object

org.cicirello.permutations.distance.ExactMatchDistance

All Implemented Interfaces:

NormalizedPermutationDistanceMeasurer, NormalizedPermutationDistanceMeasurerDouble, PermutationDistanceMeasurer, PermutationDistanceMeasurerDouble

public final class ExactMatchDistance
extends Object
implements NormalizedPermutationDistanceMeasurer

Exact Match Distance:

Exact Match distance is an extension of Hamming distance but to non-binary strings, in this case, permutations. It is the count of the number of positions for which the two permutations contain different elements.

Runtime: O(n), where n is the permutation length.

Exact match distance was introduced in:
S. Ronald, "More distance functions for order-based encodings," in Proc. IEEE CEC. IEEE Press, 1998, pp. 558–563.

Constructor Summary

Constructors

Constructor	Description
ExactMatchDistance()	Constructs the distance measurer as specified in the class documentation.

Method Summary

Modifier and Type	Method	Description
int	distance(Permutation p1, Permutation p2)	Measures the distance between two permutations.
int	max(int length)	Computes the maximum possible distance between permutations of a specified length.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.cicirello.permutations.distance.NormalizedPermutationDistanceMeasurer

maxf, normalizedDistance

Methods inherited from interface org.cicirello.permutations.distance.PermutationDistanceMeasurer

distancef

Constructor Detail

ExactMatchDistance

public ExactMatchDistance()

Constructs the distance measurer as specified in the class documentation.

Method Detail

distance

public int distance(Permutation p1,
                    Permutation p2)

Measures the distance between two permutations.

Specified by:

distance in interface PermutationDistanceMeasurer

Parameters:

p1 - first permutation

p2 - second permutation

Returns:

distance between p1 and p2

Throws:

IllegalArgumentException - if p1.length() is not equal to p2.length().

max

public int max(int length)

Description copied from interface: NormalizedPermutationDistanceMeasurer

Computes the maximum possible distance between permutations of a specified length.

Specified by:

max in interface NormalizedPermutationDistanceMeasurer

Parameters:

length - Permutation length.

Returns:

the maximum distance between a pair of permutations of the specified length.