Package weka.classifiers.trees.m5

Class Impurity

java.lang.Object

weka.classifiers.trees.m5.Impurity

All Implemented Interfaces:

RevisionHandler

public final class Impurity
extends Object
implements RevisionHandler

Class for handling the impurity values when spliting the instances

Version:

$Revision: 8034 $

Author:

Yong Wang (yongwang@cs.waikato.ac.nz)

Constructor Summary

Constructors

Constructor	Description
Impurity(int partition, int attribute, Instances inst, int k)	Constructs an Impurity object containing the impurity values of partitioning the instances using an attribute

Method Summary

Modifier and Type	Method	Description
String	getRevision()	Returns the revision string.
final void	incremental(double value, int type)	Incrementally computes the impurirty values
final String	toString()	Converts an Impurity object to a string

Methods inherited from class java.lang.Object

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

Constructor Details

Impurity

public Impurity(int partition,
 int attribute,
 Instances inst,
 int k)

Constructs an Impurity object containing the impurity values of partitioning the instances using an attribute

Parameters:

partition - the index of the last instance in the left subset

attribute - the attribute used in partitioning

inst - instances

k - the order of the impurity; =1, the variance; =2, the stardard deviation; =k, the k-th order root of the variance

Method Details

toString

public final String toString()

Converts an Impurity object to a string

Overrides:

toString in class Object

Returns:

the converted string

incremental

public final void incremental(double value,
 int type)

Incrementally computes the impurirty values

Parameters:

value - the incremental value

type - if type=1, value will be added to the left subset; type=-1, to the right subset; type=0, initializes

getRevision

public String getRevision()

Returns the revision string.

Specified by:

getRevision in interface RevisionHandler

Returns:

the revision