weka.clusterers
Class Cobweb

java.lang.Object
  weka.clusterers.Clusterer
      weka.clusterers.Cobweb

All Implemented Interfaces:

java.lang.Cloneable, Drawable, OptionHandler, java.io.Serializable

public class Cobweb

extends Clusterer

implements OptionHandler, Drawable

Class implementing the Cobweb and Classit clustering algorithms.

Note: the application of node operators (merging, splitting etc.) in terms of ordering and priority differs (and is somewhat ambiguous) between the original Cobweb and Classit papers. This algorithm always compares the best host, adding a new leaf, merging the two best hosts, and splitting the best host when considering where to place a new instance.

Valid options are:

-A
Acuity.

-C
Cutoff.

Version:

$Revision: 1.16 $

Author:

Mark Hall

See Also:

Clusterer, OptionHandler, Drawable, Serialized Form

Nested Class Summary

private class

Cobweb.CNode Inner class handling node operations for Cobweb.

Field Summary

protected double	m_acuity Acuity (minimum standard deviation).
protected Cobweb.CNode	m_cobwebTree Holds the root of the Cobweb tree.
protected double	m_cutoff Cutoff (minimum category utility).
protected static double	m_normal Normal constant.
protected int	m_numberMerges
protected int	m_numberOfClusters Number of clusters (nodes in the tree).
protected int	m_numberSplits
protected boolean	m_saveInstances Output instances in graph representation of Cobweb tree (Allows instances at nodes in the tree to be visualized in the Explorer).

Fields inherited from interface weka.core.Drawable

BayesNet, NOT_DRAWABLE, TREE

Constructor Summary

Cobweb()

Method Summary

java.lang.String	acuityTipText() Returns the tip text for this property
void	addInstance(Instance newInstance) Adds an instance to the Cobweb tree.
void	buildClusterer(Instances data) Builds the clusterer.
int	clusterInstance(Instance instance) Classifies a given instance.
java.lang.String	cutoffTipText() Returns the tip text for this property
double	getAcuity() get the acuity value
double	getCutoff() get the cutoff
java.lang.String[]	getOptions() Gets the current settings of Cobweb.
boolean	getSaveInstanceData() Get the value of saveInstances.
java.lang.String	graph() Generates the graph string of the Cobweb tree
int	graphType() Returns the type of graphs this class represents
java.util.Enumeration	listOptions() Returns an enumeration describing the available options.
static void	main(java.lang.String[] argv)
int	numberOfClusters() Returns the number of clusters.
java.lang.String	saveInstanceDataTipText() Returns the tip text for this property
void	setAcuity(double a) set the acuity.
void	setCutoff(double c) set the cutoff
void	setOptions(java.lang.String[] options) Parses a given list of options.
void	setSaveInstanceData(boolean newsaveInstances) Set the value of saveInstances.
java.lang.String	toString() Returns a description of the clusterer as a string.

Methods inherited from class weka.clusterers.Clusterer

distributionForInstance, forName, makeCopies

Methods inherited from class java.lang.Object

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

Field Detail

m_normal

protected static final double m_normal

Normal constant.

m_acuity

protected double m_acuity

Acuity (minimum standard deviation).

m_cutoff

protected double m_cutoff

Cutoff (minimum category utility).

m_cobwebTree

protected Cobweb.CNode m_cobwebTree

Holds the root of the Cobweb tree.

m_numberOfClusters

protected int m_numberOfClusters

Number of clusters (nodes in the tree).

m_numberSplits

protected int m_numberSplits

m_numberMerges

protected int m_numberMerges

m_saveInstances

protected boolean m_saveInstances

Output instances in graph representation of Cobweb tree (Allows instances at nodes in the tree to be visualized in the Explorer).

Constructor Detail

Cobweb

public Cobweb()

Method Detail

buildClusterer

public void buildClusterer(Instances data)
                    throws java.lang.Exception

Builds the clusterer.

Specified by:

buildClusterer in class Clusterer

Parameters:

data - the training instances.

Throws:

java.lang.Exception - if something goes wrong.

clusterInstance

public int clusterInstance(Instance instance)
                    throws java.lang.Exception

Classifies a given instance.

Overrides:

clusterInstance in class Clusterer

Parameters:

instance - the instance to be assigned to a cluster

Returns:

the number of the assigned cluster as an interger if the class is enumerated, otherwise the predicted value

Throws:

java.lang.Exception - if instance could not be classified successfully

numberOfClusters

public int numberOfClusters()
                     throws java.lang.Exception

Returns the number of clusters.

Specified by:

numberOfClusters in class Clusterer

Returns:

the number of clusters generated for a training dataset.

Throws:

java.lang.Exception - if something goes wrong.

addInstance

public void addInstance(Instance newInstance)
                 throws java.lang.Exception

Adds an instance to the Cobweb tree.

Parameters:

newInstance - the instance to be added

Throws:

java.lang.Exception - if something goes wrong

listOptions

public java.util.Enumeration listOptions()

Returns an enumeration describing the available options.

Specified by:

listOptions in interface OptionHandler

Returns:

an enumeration of all the available options.

setOptions

public void setOptions(java.lang.String[] options)
                throws java.lang.Exception

Parses a given list of options. Valid options are:

-A
Acuity.

-C
Cutoff.

Specified by:

setOptions in interface OptionHandler

Parameters:

options - the list of options as an array of strings

Throws:

java.lang.Exception - if an option is not supported

acuityTipText

public java.lang.String acuityTipText()

Returns the tip text for this property

Returns:

tip text for this property suitable for displaying in the explorer/experimenter gui

setAcuity

public void setAcuity(double a)

set the acuity.

Parameters:

a - the acuity value

getAcuity

public double getAcuity()

get the acuity value

Returns:

the acuity

cutoffTipText

public java.lang.String cutoffTipText()

Returns the tip text for this property

Returns:

tip text for this property suitable for displaying in the explorer/experimenter gui

setCutoff

public void setCutoff(double c)

set the cutoff

Parameters:

c - the cutof

getCutoff

public double getCutoff()

get the cutoff

Returns:

the cutoff

saveInstanceDataTipText

public java.lang.String saveInstanceDataTipText()

Returns the tip text for this property

Returns:

tip text for this property suitable for displaying in the explorer/experimenter gui

getSaveInstanceData

public boolean getSaveInstanceData()

Get the value of saveInstances.

Returns:

Value of saveInstances.

setSaveInstanceData

public void setSaveInstanceData(boolean newsaveInstances)

Set the value of saveInstances.

Parameters:

newsaveInstances - Value to assign to saveInstances.

getOptions

public java.lang.String[] getOptions()

Gets the current settings of Cobweb.

Specified by:

getOptions in interface OptionHandler

Returns:

an array of strings suitable for passing to setOptions()

toString

public java.lang.String toString()

Returns a description of the clusterer as a string.

Returns:

a string describing the clusterer.

graphType

public int graphType()

Returns the type of graphs this class represents

Specified by:

graphType in interface Drawable

Returns:

Drawable.TREE

graph

public java.lang.String graph()
                       throws java.lang.Exception

Generates the graph string of the Cobweb tree

Specified by:

graph in interface Drawable

Returns:

a String value

Throws:

java.lang.Exception - if an error occurs

main

public static void main(java.lang.String[] argv)