Package opennlp.tools.util.eval

Class CrossValidationPartitioner<E>

java.lang.Object

opennlp.tools.util.eval.CrossValidationPartitioner<E>

public class CrossValidationPartitioner<E>
extends Object

Provides access to training and test partitions for n-fold cross validation.

Cross validation is used to evaluate the performance of a classifier when only training data is available. The training set is split into n parts and the training / evaluation is performed n times on these parts. The training partition always consists of n - 1 parts and one part is used for testing.

To use the CrossValidationPartitioner a client iterates over the n stream. Each CrossValidationPartitioner.TrainingSampleStream represents one partition and is used first for training and afterwards for testing. The CrossValidationPartitioner.TestSampleStream can be obtained via the CrossValidationPartitioner.TrainingSampleStream.getTestSampleStream() method.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	CrossValidationPartitioner.TrainingSampleStream<E>	The CrossValidationPartitioner.TrainingSampleStream which iterates over all training elements.

Constructor Summary

Constructors

Constructor	Description
CrossValidationPartitioner(Collection<E> elements, int numberOfPartitions)	Initializes CrossValidationPartitioner instance.
CrossValidationPartitioner(ObjectStream<E> inElements, int numberOfPartitions)	Initializes CrossValidationPartitioner instance.

Method Summary

Modifier and Type	Method	Description
boolean	hasNext()	Checks if there are more partitions available.
CrossValidationPartitioner.TrainingSampleStream<E>	next()	Retrieves the next training and test partitions.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Details

CrossValidationPartitioner

public CrossValidationPartitioner(ObjectStream<E> inElements,
 int numberOfPartitions)

Initializes CrossValidationPartitioner instance.

Parameters:

inElements - The ObjectStream<E> that provides the elements.

numberOfPartitions - The number of partitions. Must be greater than 0.

CrossValidationPartitioner

public CrossValidationPartitioner(Collection<E> elements,
 int numberOfPartitions)

Initializes CrossValidationPartitioner instance.

Parameters:

elements - A Collection<E> that provides the elements.

numberOfPartitions - The number of partitions. Must be greater than 0.

Method Details

hasNext

public boolean hasNext()

Checks if there are more partitions available.

next

public CrossValidationPartitioner.TrainingSampleStream<E> next()
                                                        throws IOException

Retrieves the next training and test partitions.

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object