weka.clusterers

Class Cobweb

java.lang.Object

weka.clusterers.AbstractClusterer

weka.clusterers.RandomizableClusterer

weka.clusterers.Cobweb

All Implemented Interfaces:

Serializable, Cloneable, Clusterer, UpdateableClusterer, CapabilitiesHandler, Drawable, OptionHandler, Randomizable, RevisionHandler, TechnicalInformationHandler

public class Cobweb
extends RandomizableClusterer
implements Drawable, TechnicalInformationHandler, UpdateableClusterer

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.

For more information see:

D. Fisher (1987). Knowledge acquisition via incremental conceptual clustering. Machine Learning. 2(2):139-172.

J. H. Gennari, P. Langley, D. Fisher (1990). Models of incremental concept formation. Artificial Intelligence. 40:11-61.

BibTeX:

 @article{Fisher1987,
    author = {D. Fisher},
    journal = {Machine Learning},
    number = {2},
    pages = {139-172},
    title = {Knowledge acquisition via incremental conceptual clustering},
    volume = {2},
    year = {1987}
 }
 
 @article{Gennari1990,
    author = {J. H. Gennari and P. Langley and D. Fisher},
    journal = {Artificial Intelligence},
    pages = {11-61},
    title = {Models of incremental concept formation},
    volume = {40},
    year = {1990}
 }
 

Valid options are:

 -A <acuity>
  Acuity.
  (default=1.0)

 -C <cutoff>
  Cutoff.
  (default=0.002)

 -S <num>
  Random number seed.
  (default 42)

Version:

$Revision: 6790 $

Author:

Mark Hall

See Also:

RandomizableClusterer, Drawable, Serialized Form

Field Summary

Fields inherited from interface weka.core.Drawable

BayesNet, Newick, NOT_DRAWABLE, TREE

Constructor Summary

Constructors

Constructor and Description
Cobweb() default constructor

Method Summary

Modifier and Type	Method and Description
String	acuityTipText() Returns the tip text for this property
void	addInstance(Instance newInstance) Deprecated. updateClusterer(Instance) should be used instead
void	buildClusterer(Instances data) Builds the clusterer.
int	clusterInstance(Instance instance) Classifies a given instance.
String	cutoffTipText() Returns the tip text for this property
double	getAcuity() get the acuity value
Capabilities	getCapabilities() Returns default capabilities of the clusterer.
double	getCutoff() get the cutoff
String[]	getOptions() Gets the current settings of Cobweb.
String	getRevision() Returns the revision string.
boolean	getSaveInstanceData() Get the value of saveInstances.
TechnicalInformation	getTechnicalInformation() Returns an instance of a TechnicalInformation object, containing detailed information about the technical background of this class, e.g., paper reference or book this class is based on.
String	globalInfo() Returns a string describing this clusterer
String	graph() Generates the graph string of the Cobweb tree
int	graphType() Returns the type of graphs this class represents
Enumeration	listOptions() Returns an enumeration describing the available options.
static void	main(String[] argv) Main method.
int	numberOfClusters() Returns the number of clusters.
String	saveInstanceDataTipText() Returns the tip text for this property
String	seedTipText() Returns the tip text for this property
void	setAcuity(double a) set the acuity.
void	setCutoff(double c) set the cutoff
void	setOptions(String[] options) Parses a given list of options.
void	setSaveInstanceData(boolean newsaveInstances) Set the value of saveInstances.
String	toString() Returns a description of the clusterer as a string.
void	updateClusterer(Instance newInstance) Adds an instance to the clusterer.
void	updateFinished() Singals the end of the updating.

Methods inherited from class weka.clusterers.RandomizableClusterer

getSeed, setSeed

Methods inherited from class weka.clusterers.AbstractClusterer

distributionForInstance, forName, makeCopies, makeCopy

Methods inherited from class java.lang.Object

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

Constructor Detail

Cobweb

public Cobweb()

default constructor

Method Detail

globalInfo

public String globalInfo()

Returns a string describing this clusterer

Returns:

a description of the evaluator suitable for displaying in the explorer/experimenter gui

getTechnicalInformation

public TechnicalInformation getTechnicalInformation()

Returns an instance of a TechnicalInformation object, containing detailed information about the technical background of this class, e.g., paper reference or book this class is based on.

Specified by:

getTechnicalInformation in interface TechnicalInformationHandler

Returns:

the technical information about this class

getCapabilities

public Capabilities getCapabilities()

Returns default capabilities of the clusterer.

Specified by:

getCapabilities in interface Clusterer

Specified by:

getCapabilities in interface CapabilitiesHandler

Overrides:

getCapabilities in class AbstractClusterer

Returns:

the capabilities of this clusterer

See Also:

Capabilities

buildClusterer

public void buildClusterer(Instances data)
                    throws Exception

Builds the clusterer.

Specified by:

buildClusterer in interface Clusterer

Specified by:

buildClusterer in class AbstractClusterer

Parameters:

data - the training instances.

Throws:

Exception - if something goes wrong.

updateFinished

public void updateFinished()

Singals the end of the updating.

Specified by:

updateFinished in interface UpdateableClusterer

clusterInstance

public int clusterInstance(Instance instance)
                    throws Exception

Classifies a given instance.

Specified by:

clusterInstance in interface Clusterer

Overrides:

clusterInstance in class AbstractClusterer

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:

Exception - if instance could not be classified successfully

numberOfClusters

public int numberOfClusters()

Returns the number of clusters.

Specified by:

numberOfClusters in interface Clusterer

Specified by:

numberOfClusters in class AbstractClusterer

Returns:

the number of clusters

updateClusterer

public void updateClusterer(Instance newInstance)
                     throws Exception

Adds an instance to the clusterer.

Specified by:

updateClusterer in interface UpdateableClusterer

Parameters:

newInstance - the instance to be added

Throws:

Exception - if something goes wrong

addInstance

public void addInstance(Instance newInstance)
                 throws Exception

Deprecated. updateClusterer(Instance) should be used instead

Adds an instance to the Cobweb tree.

Parameters:

newInstance - the instance to be added

Throws:

Exception - if something goes wrong

See Also:

updateClusterer(Instance)

listOptions

public Enumeration listOptions()

Returns an enumeration describing the available options.

Specified by:

listOptions in interface OptionHandler

Overrides:

listOptions in class RandomizableClusterer

Returns:

an enumeration of all the available options.

setOptions

public void setOptions(String[] options)
                throws Exception

Parses a given list of options.

Valid options are:

 -A <acuity>
  Acuity.
  (default=1.0)

 -C <cutoff>
  Cutoff.
  (default=0.002)

 -S <num>
  Random number seed.
  (default 42)

Specified by:

setOptions in interface OptionHandler

Overrides:

setOptions in class RandomizableClusterer

Parameters:

options - the list of options as an array of strings

Throws:

Exception - if an option is not supported

acuityTipText

public 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 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 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 String[] getOptions()

Gets the current settings of Cobweb.

Specified by:

getOptions in interface OptionHandler

Overrides:

getOptions in class RandomizableClusterer

Returns:

an array of strings suitable for passing to setOptions()

toString

public String toString()

Returns a description of the clusterer as a string.

Overrides:

toString in class Object

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 String graph()
             throws Exception

Generates the graph string of the Cobweb tree

Specified by:

graph in interface Drawable

Returns:

a String value

Throws:

Exception - if an error occurs

getRevision

public String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Overrides:

getRevision in class AbstractClusterer

Returns:

the revision

seedTipText

public String seedTipText()

Returns the tip text for this property

Overrides:

seedTipText in class RandomizableClusterer

Returns:

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

main

public static void main(String[] argv)

Main method.

Parameters:

argv - the commandline options