KCycleDistance (JavaPermutationTools - A Java library for computation on permutations)

java.lang.Object
- org.cicirello.permutations.distance.KCycleDistance

All Implemented Interfaces:

NormalizedPermutationDistanceMeasurer, NormalizedPermutationDistanceMeasurerDouble, PermutationDistanceMeasurer, PermutationDistanceMeasurerDouble
```
public final class KCycleDistance
extends Object
implements NormalizedPermutationDistanceMeasurer
```
K-Cycle distance is the count of the number of non-singleton permutation cycles of length at most K. Specifically, each non-singleton cycle contributes to the total distance the number of cycles of length at most K necessary to transform the cycle to all fixed points. K-cycle distance is a metric provided that K ≤ 4. However, if K > 4, it is only a semi-metric because it fails to satisfy the triangle inequality when K ≥ 5.

K-Cycle distance was introduced in the following article:

Vincent A. Cicirello. 2022. Cycle Mutation: Evolving Permutations via Cycle Induction, Applied Sciences, 12(11), Article 5506 (June 2022). doi:10.3390/app12115506

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

Constructor Summary

Constructors
Constructor Description

KCycleDistance(int k)
Constructs the distance measurer as specified in the class documentation.

Method Summary

All Methods Instance Methods Concrete Methods
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
  - KCycleDistance
```
public KCycleDistance(int k)
```
    Constructs the distance measurer as specified in the class documentation.
    
    Parameters:
    
    k - The maximum length cycle that is considered an atomic edit operation, such that k is greater than or equal to 2.
    
    Throws:
    
    IllegalArgumentException - if k is less than 2
- 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.