Package org.cicirello.sequences.distance

Class ExactMatchDistance

java.lang.Object

org.cicirello.sequences.distance.ExactMatchDistance

All Implemented Interfaces:

SequenceDistanceMeasurer, SequenceDistanceMeasurerDouble

public final class ExactMatchDistance
extends Object
implements SequenceDistanceMeasurer

ExactMatch distance (or Hamming Distance) of a pair of non-binary strings (or more generally sequences) is the number of sequence (or string) positions where the two sequences differ. This class supports comparison of Java String objects, as well as comparisons of arrays of any of Java's eight primitive types, and arrays of any object type. It is the count of the number of positions for which the two sequences contain different elements.

Most other implementations of Hamming distance require the two strings to be of the same length. Ours does not. If the two sequences (i.e., arrays or Strings) are of different lengths, then the difference in length affects distance. E.g., although "abbd" is a distance of 1 from "abcd" since they differ in one position, "abbd" is a distance of 4 from "abcdefg" (the one difference, plus the three extra characters).

Runtime: O(n), where n is the length of the shorter of the two sequences.

If your sequences are guaranteed not to have duplicates, and to contain the same set of elements, then consider instead using the ExactMatchDistance class, which assumes permutations of the integers from 0 to N-1.

Exact match distance was introduced specifically for permutations in:
S. Ronald, "More distance functions for order-based encodings," in Proc. IEEE CEC. IEEE Press, 1998, pp. 558–563.

Constructor Summary

Constructors

Constructor	Description
ExactMatchDistance()	Constructs the distance measurer as specified in the class documentation.

Method Summary

Modifier and Type	Method	Description
int	distance(boolean[] s1, boolean[] s2)	Measures the distance between two arrays.
int	distance(byte[] s1, byte[] s2)	Measures the distance between two arrays.
int	distance(char[] s1, char[] s2)	Measures the distance between two arrays.
int	distance(double[] s1, double[] s2)	Measures the distance between two arrays.
int	distance(float[] s1, float[] s2)	Measures the distance between two arrays.
int	distance(int[] s1, int[] s2)	Measures the distance between two arrays.
int	distance(long[] s1, long[] s2)	Measures the distance between two arrays.
int	distance(short[] s1, short[] s2)	Measures the distance between two arrays.
int	distance(Object[] s1, Object[] s2)	Measures the distance between two arrays of objects.
int	distance(String s1, String s2)	Measures the distance between two Strings.
<T> int	distance(List<T> s1, List<T> s2)	Measures the distance between two lists of objects.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.cicirello.sequences.distance.SequenceDistanceMeasurer

distancef, distancef, distancef, distancef, distancef, distancef, distancef, distancef, distancef, distancef, distancef

Constructor Detail

ExactMatchDistance

public ExactMatchDistance()

Constructs the distance measurer as specified in the class documentation.

Method Detail

distance

public int distance(int[] s1,
                    int[] s2)

Description copied from interface: SequenceDistanceMeasurer

Measures the distance between two arrays.

Specified by:

distance in interface SequenceDistanceMeasurer

Parameters:

s1 - First array.

s2 - Second array.

Returns:

distance between s1 and s2

distance

public int distance(long[] s1,
                    long[] s2)

Description copied from interface: SequenceDistanceMeasurer

Measures the distance between two arrays.

Specified by:

distance in interface SequenceDistanceMeasurer

Parameters:

s1 - First array.

s2 - Second array.

Returns:

distance between s1 and s2

distance

public int distance(short[] s1,
                    short[] s2)

Description copied from interface: SequenceDistanceMeasurer

Measures the distance between two arrays.

Specified by:

distance in interface SequenceDistanceMeasurer

Parameters:

s1 - First array.

s2 - Second array.

Returns:

distance between s1 and s2

distance

public int distance(byte[] s1,
                    byte[] s2)

Description copied from interface: SequenceDistanceMeasurer

Measures the distance between two arrays.

Specified by:

distance in interface SequenceDistanceMeasurer

Parameters:

s1 - First array.

s2 - Second array.

Returns:

distance between s1 and s2

distance

public int distance(char[] s1,
                    char[] s2)

Description copied from interface: SequenceDistanceMeasurer

Measures the distance between two arrays.

Specified by:

distance in interface SequenceDistanceMeasurer

Parameters:

s1 - First array.

s2 - Second array.

Returns:

distance between s1 and s2

distance

public int distance(boolean[] s1,
                    boolean[] s2)

Description copied from interface: SequenceDistanceMeasurer

Measures the distance between two arrays.

Specified by:

distance in interface SequenceDistanceMeasurer

Parameters:

s1 - First array.

s2 - Second array.

Returns:

distance between s1 and s2

distance

public int distance(double[] s1,
                    double[] s2)

Description copied from interface: SequenceDistanceMeasurer

Measures the distance between two arrays.

Specified by:

distance in interface SequenceDistanceMeasurer

Parameters:

s1 - First array.

s2 - Second array.

Returns:

distance between s1 and s2

distance

public int distance(float[] s1,
                    float[] s2)

Description copied from interface: SequenceDistanceMeasurer

Measures the distance between two arrays.

Specified by:

distance in interface SequenceDistanceMeasurer

Parameters:

s1 - First array.

s2 - Second array.

Returns:

distance between s1 and s2

distance

public int distance(String s1,
                    String s2)

Description copied from interface: SequenceDistanceMeasurer

Measures the distance between two Strings.

Specified by:

distance in interface SequenceDistanceMeasurer

Parameters:

s1 - First String.

s2 - Second String.

Returns:

distance between s1 and s2

distance

public int distance(Object[] s1,
                    Object[] s2)

Description copied from interface: SequenceDistanceMeasurer

Measures the distance between two arrays of objects. The objects in the arrays must be of a class that has overridden the Object.equals method.

Specified by:

distance in interface SequenceDistanceMeasurer

Parameters:

s1 - First array.

s2 - Second array.

Returns:

distance between s1 and s2

distance

public <T> int distance(List<T> s1,
                        List<T> s2)

Description copied from interface: SequenceDistanceMeasurer

Measures the distance between two lists of objects. The objects in the lists must be of a class that has overridden the Object.equals method.

Specified by:

distance in interface SequenceDistanceMeasurer

Type Parameters:

T - Type of List elements.

Parameters:

s1 - First list.

s2 - Second list.

Returns:

distance between s1 and s2