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 CrossValidationPartioner a client iterates over the n TrainingSampleStreams. Each TrainingSampleStream represents one partition and is used first for training and afterwards for testing. The TestSampleStream can be obtained from the TrainingSampleStream with the getTestSampleStream method.

Nested Class Summary

static class

CrossValidationPartitioner.TrainingSampleStream<E> The TrainingSampleStream which iterates over all training elements.

Constructor Summary

CrossValidationPartitioner(Collection<E> elements, int numberOfPartitions)
Initializes the current instance.

CrossValidationPartitioner(ObjectStream<E> inElements, int numberOfPartitions)
Initializes the current instance.

Method Summary

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

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

Constructor Detail

CrossValidationPartitioner

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

Initializes the current instance.

Parameters:

inElements -

numberOfPartitions -

CrossValidationPartitioner

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

Initializes the current instance.

Parameters:

elements -

numberOfPartitions -

Method Detail

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