edu.udo.cs.yale.example
Class StratifiedPartitionBuilder

java.lang.Object
  edu.udo.cs.yale.example.StratifiedPartitionBuilder

All Implemented Interfaces:

PartitionBuilder

public class StratifiedPartitionBuilder
extends java.lang.Object
implements PartitionBuilder

Creates a shuffled and stratified partition for an example set. The example set must have an nominal label. This partition builder can work in two modes:

1. The first working mode is automatically used for generic types of ratio arrays, especially for those with different sizes. Due to to this fact it however cannot longer be guaranteed that each fold exactly contains the correct number of examples and each class at least once.
2. In contrast to the first mode the correct partition can at least be guaranteed for ratio arrays containing the same ratio value for all folds. The second mode is automatically performed in this case (e.g. for cross validation).

Version:

$Id: StratifiedPartitionBuilder.java,v 2.10 2006/03/27 13:21:58 ingomierswa Exp $

Author:

Ingo Mierswa

Nested Class Summary

private static class

StratifiedPartitionBuilder.ExampleIndex Helper class for sorting according to class values.

Field Summary

private ExampleSet	exampleSet
private java.util.Random	random

Constructor Summary

StratifiedPartitionBuilder(ExampleSet exampleSet, int seed)



Method Summary

private int[]	createEqualPartition(double[] ratio, int size, Attribute label) Returns a stratified partition for the given example set.
private int[]	createNonEqualPartition(double[] ratio, int size, Attribute label) Returns a stratified partition for the given example set.
int[]	createPartition(double[] ratio, int size) Returns a stratified partition for the given example set.

Methods inherited from class java.lang.Object

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

Field Detail

exampleSet

private ExampleSet exampleSet

random

private java.util.Random random

Constructor Detail

StratifiedPartitionBuilder

public StratifiedPartitionBuilder(ExampleSet exampleSet,
                                  int seed)

Method Detail

createPartition

public int[] createPartition(double[] ratio,
                             int size)

Returns a stratified partition for the given example set. The examples must have an nominal label.

Specified by:

createPartition in interface PartitionBuilder

createEqualPartition

private int[] createEqualPartition(double[] ratio,
                                   int size,
                                   Attribute label)

Returns a stratified partition for the given example set. The examples must have an nominal label.

createNonEqualPartition

private int[] createNonEqualPartition(double[] ratio,
                                      int size,
                                      Attribute label)

Returns a stratified partition for the given example set. The examples must have an nominal label. In contrast to createEqualPartition(double[], int, Attribute) this method does not require the equal ratio values.