opennlp.maxent
Class TwoPassDataIndexer

java.lang.Object
  opennlp.maxent.AbstractDataIndexer
      opennlp.maxent.TwoPassDataIndexer

All Implemented Interfaces:

DataIndexer

public class TwoPassDataIndexer
extends AbstractDataIndexer

Collecting event and context counts by making two passes over the events. The first pass determines which contexts will be used by the model, and the second pass creates the events in memory containing only the contexts which will be used. This greatly reduces the amount of memory required for storing the events. During the first pass a temporary event file is created which is read during the second pass.

Field Summary

Fields inherited from class opennlp.maxent.AbstractDataIndexer

contexts, numTimesEventsSeen, outcomeLabels, outcomeList, predCounts, predLabels

Constructor Summary

TwoPassDataIndexer(EventStream eventStream)
One argument constructor for DataIndexer which calls the two argument constructor assuming no cutoff.

TwoPassDataIndexer(EventStream eventStream, int cutoff)
Two argument constructor for DataIndexer.

Method Summary

Methods inherited from class opennlp.maxent.AbstractDataIndexer

getContexts, getNumTimesEventsSeen, getOutcomeLabels, getOutcomeList, getPredCounts, getPredLabels, getValues, sortAndMerge, toIndexedStringArray, update

Methods inherited from class java.lang.Object

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

Constructor Detail

TwoPassDataIndexer

public TwoPassDataIndexer(EventStream eventStream)
                   throws java.io.IOException

One argument constructor for DataIndexer which calls the two argument constructor assuming no cutoff.

Parameters:

eventStream - An Event[] which contains the a list of all the Events seen in the training data.

Throws:

java.io.IOException

TwoPassDataIndexer

public TwoPassDataIndexer(EventStream eventStream,
                          int cutoff)
                   throws java.io.IOException

Two argument constructor for DataIndexer.

Parameters:

eventStream - An Event[] which contains the a list of all the Events seen in the training data.

cutoff - The minimum number of times a predicate must have been observed in order to be included in the model.

Throws:

java.io.IOException