 java.lang.Object

 org.cicirello.permutations.distance.RTypeDistance

 All Implemented Interfaces:
NormalizedPermutationDistanceMeasurer
,NormalizedPermutationDistanceMeasurerDouble
,PermutationDistanceMeasurer
,PermutationDistanceMeasurerDouble
public final class RTypeDistance extends Object implements NormalizedPermutationDistanceMeasurer
RType Distance:RType distance treats the permutations as if they represent sets of directed edges, and counts the number of edges that differ.
Consider the example permutation: [1, 5, 2, 4, 0, 3]. RType distance treats this as equivalent to the set of directed edges: {(1,5), (5,2), (2,4), (4,0), (0,3)}.
E.g., distance between [1, 5, 2, 4, 0, 3] and [ 5, 1, 4, 0, 3, 2] is 3. Why? Well, the first permutation has the directed edges: {(1,5), (5,2), (2,4), (4,0), (0,3)}. The second has 2 of these (4,0), and (0,3), but does not include 3 of the edges: (1,5), (5,2), (2,4)
Runtime: O(n), where n is the permutation length.
RType distance was introduced in:
V. Campos, M. Laguna, and R. Marti, "Contextindependent scatter and tabu search for permutation problems," INFORMS Journal on Computing, vol. 17, no. 1, pp. 111–122, 2005.


Constructor Summary
Constructors Constructor Description RTypeDistance()
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




Method Detail

distance
public int distance(Permutation p1, Permutation p2)
Measures the distance between two permutations. Specified by:
distance
in interfacePermutationDistanceMeasurer
 Parameters:
p1
 first permutationp2
 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 interfaceNormalizedPermutationDistanceMeasurer
 Parameters:
length
 Permutation length. Returns:
 the maximum distance between a pair of permutations of the specified length.

