Class AcyclicEdgeDistance
- java.lang.Object
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- org.cicirello.permutations.distance.AcyclicEdgeDistance
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- All Implemented Interfaces:
NormalizedPermutationDistanceMeasurer
,NormalizedPermutationDistanceMeasurerDouble
,PermutationDistanceMeasurer
,PermutationDistanceMeasurerDouble
public final class AcyclicEdgeDistance extends Object
Acyclic Edge Distance: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.
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Constructor Summary
Constructors Constructor Description AcyclicEdgeDistance()
Constructs the distance measurer as specified in the class documentation.
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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.double
distancef(Permutation p1, Permutation p2)
Measures the distance between two permutationsint
max(int length)
Computes the maximum possible distance between permutations of a specified length.double
maxf(int length)
Computes the maximum possible distance between permutations of a specified length.double
normalizedDistance(Permutation p1, Permutation p2)
Measures the distance between two permutations, normalized to the interval [0.0, 1.0].
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Method Detail
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distance
public int distance(Permutation p1, Permutation p2)
Measures the distance between two permutations.- Parameters:
p1
- first permutationp2
- second permutation- Returns:
- distance between p1 and p2
- Throws:
IllegalArgumentException
- if p1.length() is not equal to p2.length().
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max
public int max(int length)
Description copied from interface:NormalizedPermutationDistanceMeasurer
Computes the maximum possible distance between permutations of a specified length.- Parameters:
length
- Permutation length.- Returns:
- the maximum distance between a pair of permutations of the specified length.
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distancef
public final double distancef(Permutation p1, Permutation p2)
Measures the distance between two permutations- Specified by:
distancef
in interfacePermutationDistanceMeasurerDouble
- Parameters:
p1
- first permutationp2
- second permutation- Returns:
- distance between p1 and p2
- Throws:
IllegalArgumentException
- if p1.length() is not equal to p2.length().
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maxf
public final double maxf(int length)
Description copied from interface:NormalizedPermutationDistanceMeasurerDouble
Computes the maximum possible distance between permutations of a specified length.- Specified by:
maxf
in interfaceNormalizedPermutationDistanceMeasurerDouble
- Parameters:
length
- Permutation length.- Returns:
- the maximum distance between a pair of permutations of the specified length.
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normalizedDistance
public final double normalizedDistance(Permutation p1, Permutation p2)
Measures the distance between two permutations, normalized to the interval [0.0, 1.0].
- Specified by:
normalizedDistance
in interfaceNormalizedPermutationDistanceMeasurerDouble
- Parameters:
p1
- first permutationp2
- second permutation- Returns:
- distance between p1 and p2 normalized to the interval [0.0, 1.0]
- Throws:
IllegalArgumentException
- if p1.length() is not equal to p2.length().
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