coreComponents
Class DistanceMetric

java.lang.Object
  |
  +--coreComponents.DistanceMetric

Direct Known Subclasses:

EuclideanDistanceMetric, USMDistanceFunction, ValueDifferenceMetric

public abstract class DistanceMetric

extends java.lang.Object

Abstract class for implementing specialised distance measures.

Version:

$Version: 1.0$

Author:

David Lindsay (davidl@cs.rhul.ac.uk)

Constructor Summary

DistanceMetric()

Method Summary

abstract boolean	checkInstances(Instances instances) Check if the instances are valid for the distance metric.
abstract double	distance(Instance inst1, Instance inst2) Calculates the distance between two instances.
static DistanceMetric	forName(java.lang.String distanceMetricName, java.lang.String[] options) Creates a new instance of a distance metric given it's class name and (optional) arguments to pass to it's setOptions method.
abstract void	reset(Instances instances) This function is useful if we need to reinitialise the distance metric without using the constructor
abstract java.lang.String	toString() Creates a debugging string detailing the information about the distance metric
abstract void	updateRanges(Instance inst1) Update the ranges of the distance metric with a new training instance.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

DistanceMetric

public DistanceMetric()

Method Detail

reset

public abstract void reset(Instances instances)

This function is useful if we need to reinitialise the distance metric without using the constructor

distance

public abstract double distance(Instance inst1,
                                Instance inst2)

Calculates the distance between two instances.

Parameters:

inst1 - the first instance

inst2 - the second instance

Returns:

the distance between the two instances

toString

public abstract java.lang.String toString()

Creates a debugging string detailing the information about the distance metric

Overrides:

toString in class java.lang.Object

Returns:

a debugging string

updateRanges

public abstract void updateRanges(Instance inst1)

Update the ranges of the distance metric with a new training instance.

Parameters:

inst1 - the instance to update with

Returns:

nothing

checkInstances

public abstract boolean checkInstances(Instances instances)

Check if the instances are valid for the distance metric.

Parameters:

instances - the training instances to be checked

Returns:

true if the instances are valid, false otherwise

forName

public static DistanceMetric forName(java.lang.String distanceMetricName,
                                     java.lang.String[] options)
                              throws java.lang.Exception

Creates a new instance of a distance metric given it's class name and (optional) arguments to pass to it's setOptions method. If the distance metric implements OptionHandler and the options parameter is non-null, the distance metric will have it's options set.

Parameters:

distanceMetricName - the fully qualified class name of the

options - an array of options suitable for passing to setOptions. May be null.

Returns:

the newly created distance metric, ready for use.

Throws:

java.lang.Exception - if the distance metric name is invalid, or the options supplied are not acceptable to the distance metric