net.sourceforge.cilib.util
Class MinkowskiMetric

java.lang.Object
  net.sourceforge.cilib.util.MinkowskiMetric

All Implemented Interfaces:

DistanceMeasure

Direct Known Subclasses:

ChebyshevDistanceMeasure, EuclideanDistanceMeasure, ManhattanDistanceMeasure

public class MinkowskiMetric
extends Object
implements DistanceMeasure

The Minkowski Metric is a generic measure of distance. It is defined in:

 Article{ 331504, author = "A. K. Jain and M. N. Murty and P. J. Flynn", title = "Data
           Clustering: A Review", journal = "ACM Computing Surveys", volume = "31", number = "3",
           year = "1999", issn = "0360-0300", pages = "264--323", doi =
           "http://0-doi.acm.org.innopac.up.ac.za:80/10.1145/331499.331504", publisher = "ACM
           Press", address = "New York, NY, USA" }
 

Manhattan Distance is a special case of the Minkowski Metric with 'alpha' := 1.
Euclidean Distance is a special case of the Minkowski Metric with 'alpha' := 2.

NOTE: The default 'alpha' value is 0 when this class is instantiated.

Author:

Theuns Cloete

Field Summary

protected int

alpha

Constructor Summary

MinkowskiMetric()
Instantiate the Minkowski Metric with 'alpha' value equal to zero.

MinkowskiMetric(int a)
Instantiate the Minkowski Metric with the specified 'alpha' value.

Method Summary

<T extends Collection<? extends Number>> double	distance(T x, T y) Calculate the distance between two vectors represented by Java Collection objects.
<T extends Type,U extends StructuredType<T>> double	distance(U x, U y) Calculate the distance between two vectors.
void	setAlpha(int a) Set the 'alpha' value that will be used in the calculation of the Minkowski Metric.

Methods inherited from class java.lang.Object

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

Field Detail

alpha

protected int alpha

Constructor Detail

MinkowskiMetric

public MinkowskiMetric()

Instantiate the Minkowski Metric with 'alpha' value equal to zero. This means that you have to call the setAlpha method right after calling this constructor.

MinkowskiMetric

public MinkowskiMetric(int a)

Instantiate the Minkowski Metric with the specified 'alpha' value.

Parameters:

a - the value to which 'alpha' should be set

Method Detail

distance

public <T extends Type,U extends StructuredType<T>> double distance(U x,
                                                                    U y)

Calculate the distance between two vectors.

Specified by:

distance in interface DistanceMeasure

Parameters:

x - the one vector.

y - the other vector.

Returns:

the distance (as a double) between the two vectors.

Throws:

IllegalArgumentException - when the two vectors' dimension differ.

distance

public <T extends Collection<? extends Number>> double distance(T x,
                                                                T y)

Calculate the distance between two vectors represented by Java Collection objects.

Specified by:

distance in interface DistanceMeasure

Type Parameters:

T - The Collection type.

Parameters:

x - the one Java Collection object.

y - the other Java Collection object.

Returns:

the distance (as a double) between the two vectors.

Throws:

IllegalArgumentException - when the two vectors' dimension differ.

setAlpha

public void setAlpha(int a)

Set the 'alpha' value that will be used in the calculation of the Minkowski Metric.

Parameters:

a - the new 'alpha' value

Throws:

IllegalArgumentException - when the given parameter is less than one.