Module org.cicirello.jpt
Package org.cicirello.permutations.distance

Class AcyclicEdgeDistance

  • All Implemented Interfaces:
    NormalizedPermutationDistanceMeasurer, NormalizedPermutationDistanceMeasurerDouble, PermutationDistanceMeasurer, PermutationDistanceMeasurerDouble
    public final class AcyclicEdgeDistance
extends Object
implements NormalizedPermutationDistanceMeasurer

    Acyclic edge distance treats the permutations as if they represent sets of edges, and counts the number of edges that differ.

    Consider the example permutation: [1, 5, 2, 4, 0, 3]. Acyclic edge distance treats this as equivalent to the set of undirected 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 2. Why? Well, the first permutation has the edges: {(1,5), (5,2), (2,4), (4,0), (0,3)}. The second has three of these (5,1), which is the same as (1,5) since they are undirected edges, (4,0), and (0,3), but does not include two of the edges: (5,2), (2,4)

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

    Acyclic edge distance was first described in:
    S. Ronald, "Distance functions for order-based encodings," in Proc. IEEE CEC. IEEE Press, 1997, pp. 49–54.

    • Constructor Detail

      • AcyclicEdgeDistance

        public AcyclicEdgeDistance()
        Constructs the distance measurer as specified in the class documentation.