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## weka.clusterers
Class Cobweb

    java.lang.Object
      weka.clusterers.AbstractClusterer
          weka.clusterers.RandomizableClusterer
              weka.clusterers.Cobweb

All Implemented Interfaces:
  java.io.Serializable, java.lang.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: 5488 $
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
`Cobweb()` default constructor

Method Summary
`java.lang.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.
`java.lang.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
`java.lang.String[]` | `getOptions()` Gets the current settings of Cobweb.
`java.lang.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.
`java.lang.String` | `globalInfo()` Returns a string describing this clusterer
`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)` Main method.
`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.
`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, seedTipText, 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 java.lang.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 java.lang.Exception

  Builds the clusterer.

  Specified by:
    `buildClusterer` in interface `Clusterer`
  Specified by:
    `buildClusterer` in class `AbstractClusterer`
  Parameters:
    `data` - the training instances.
  Throws:
    `java.lang.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 java.lang.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:
    `java.lang.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 java.lang.Exception

  Adds an instance to the clusterer.

  Specified by:
    `updateClusterer` in interface `UpdateableClusterer`
  Parameters:
    `newInstance` - the instance to be added
  Throws:
    `java.lang.Exception` - if something goes wrong

### addInstance

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

  Deprecated. updateClusterer(Instance) should be used instead

  Adds an instance to the Cobweb tree.

  Parameters:
    `newInstance` - the instance to be added
  Throws:
    `java.lang.Exception` - if something goes wrong
  See Also:
    `updateClusterer(Instance)`

### listOptions

    public java.util.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(java.lang.String[] options)
                    throws java.lang.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:
    `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`
  Overrides:
    `getOptions` in class `RandomizableClusterer`
  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.

  Overrides:
    `toString` in class `java.lang.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 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

### getRevision

    public java.lang.String getRevision()

  Returns the revision string.

  Specified by:
    `getRevision` in interface `RevisionHandler`
  Overrides:
    `getRevision` in class `AbstractClusterer`
  Returns:
    the revision

### main

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

  Main method.

  Parameters:
    `argv` - the commandline options

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