public class BlockInterchangeDistance extends Object
Block Interchange Distance is the minimum number of block interchanges necessary to transform one permutation into the other. A block interchange is an edit operation that takes two non-overlapping blocks (i.e., subsequence) and exchanges their locations in the permutation. For example, the permutation p1 = [0, 1, 2, 3, 4, 5, 6, 7] and p2 = [5, 6, 3, 4, 0, 1, 2, 7] is a block interchange distance of 1 since you can transform p2 into p1 by exchanging the blocks [5, 6] and [0, 1, 2] within p2.
Interchange distance is computed efficiently using the algorithm described in the article: D.A. Christie, "Sorting permutations by block-interchanges," Information Processing Letters, vol 60, pages 165-169, 1996.
Runtime: O(n), where n is the permutation length.
| Constructor and Description |
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BlockInterchangeDistance()
Constructs the distance measurer as specified in the class documentation.
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| Modifier and Type | Method and Description |
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int |
distance(Permutation p1,
Permutation p2)
Measures the distance between two permutations.
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double |
distancef(Permutation p1,
Permutation p2)
Measures the distance between two permutations
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int |
max(int length)
Computes the maximum possible distance between permutations
of a specified length.
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double |
maxf(int length)
Computes the maximum possible distance between permutations
of a specified length.
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double |
normalizedDistance(Permutation p1,
Permutation p2)
Measures the distance between two permutations, normalized to the interval [0.0, 1.0].
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public BlockInterchangeDistance()
public int distance(Permutation p1, Permutation p2)
p1 - first permutationp2 - second permutationpublic int max(int length)
length - Permutation length.public final double distancef(Permutation p1, Permutation p2)
distancef in interface PermutationDistanceMeasurerDoublep1 - first permutationp2 - second permutationpublic final double maxf(int length)
maxf in interface NormalizedPermutationDistanceMeasurerDoublelength - Permutation length.public final double normalizedDistance(Permutation p1, Permutation p2)
Measures the distance between two permutations, normalized to the interval [0.0, 1.0].
normalizedDistance in interface NormalizedPermutationDistanceMeasurerDoublep1 - first permutationp2 - second permutationCopyright © 2005-2020 Vincent A. Cicirello. All rights reserved.