weka.classifiers.trees
Class DecisionStump

java.lang.Object
  extended by weka.classifiers.Classifier
      extended by weka.classifiers.trees.DecisionStump
All Implemented Interfaces:
java.io.Serializable, java.lang.Cloneable, Sourcable, CapabilitiesHandler, OptionHandler, WeightedInstancesHandler

public class DecisionStump
extends Classifier
implements WeightedInstancesHandler, Sourcable

Class for building and using a decision stump. Usually used in conjunction with a boosting algorithm. Does regression (based on mean-squared error) or classification (based on entropy). Missing is treated as a separate value.

Typical usage:

java weka.classifiers.trees.LogitBoost -I 100 -W weka.classifiers.trees.DecisionStump -t training_data

Valid options are:

 -D
  If set, classifier is run in debug mode and
  may output additional info to the console

Version:
$Revision: 1.25 $
Author:
Eibe Frank (eibe@cs.waikato.ac.nz)
See Also:
Serialized Form

Constructor Summary
DecisionStump()
           
 
Method Summary
 void buildClassifier(Instances instances)
          Generates the classifier.
 double[] distributionForInstance(Instance instance)
          Calculates the class membership probabilities for the given test instance.
 Capabilities getCapabilities()
          Returns default capabilities of the classifier.
 java.lang.String globalInfo()
          Returns a string describing classifier
static void main(java.lang.String[] argv)
          Main method for testing this class.
 java.lang.String toSource(java.lang.String className)
          Returns the decision tree as Java source code.
 java.lang.String toString()
          Returns a description of the classifier.
 
Methods inherited from class weka.classifiers.Classifier
classifyInstance, debugTipText, forName, getDebug, getOptions, listOptions, makeCopies, makeCopy, setDebug, setOptions
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

DecisionStump

public DecisionStump()
Method Detail

globalInfo

public java.lang.String globalInfo()
Returns a string describing classifier

Returns:
a description suitable for displaying in the explorer/experimenter gui

getCapabilities

public Capabilities getCapabilities()
Returns default capabilities of the classifier.

Specified by:
getCapabilities in interface CapabilitiesHandler
Overrides:
getCapabilities in class Classifier
Returns:
the capabilities of this classifier
See Also:
Capabilities

buildClassifier

public void buildClassifier(Instances instances)
                     throws java.lang.Exception
Generates the classifier.

Specified by:
buildClassifier in class Classifier
Parameters:
instances - set of instances serving as training data
Throws:
java.lang.Exception - if the classifier has not been generated successfully

distributionForInstance

public double[] distributionForInstance(Instance instance)
                                 throws java.lang.Exception
Calculates the class membership probabilities for the given test instance.

Overrides:
distributionForInstance in class Classifier
Parameters:
instance - the instance to be classified
Returns:
predicted class probability distribution
Throws:
java.lang.Exception - if distribution can't be computed

toSource

public java.lang.String toSource(java.lang.String className)
                          throws java.lang.Exception
Returns the decision tree as Java source code.

Specified by:
toSource in interface Sourcable
Parameters:
className - the classname of the generated code
Returns:
the tree as Java source code
Throws:
java.lang.Exception - if something goes wrong

toString

public java.lang.String toString()
Returns a description of the classifier.

Overrides:
toString in class java.lang.Object
Returns:
a description of the classifier as a string.

main

public static void main(java.lang.String[] argv)
Main method for testing this class.

Parameters:
argv - the options