edu.northwestern.at.morphadorner.corpuslinguistics.postagger.smoothing.lexical

Class AdditiveLexicalSmoother

java.lang.Object

edu.northwestern.at.utils.IsCloseableObject

edu.northwestern.at.morphadorner.corpuslinguistics.postagger.smoothing.lexical.AbstractLexicalSmoother

edu.northwestern.at.morphadorner.corpuslinguistics.postagger.smoothing.lexical.AdditiveLexicalSmoother

All Implemented Interfaces:

LexicalSmoother, UsesLogger

Direct Known Subclasses:

DefaultLexicalSmoother

public class AdditiveLexicalSmoother
extends AbstractLexicalSmoother
implements LexicalSmoother

Additive lexical smoother.

A lexical smoother which adds a small positive value to each (word, tag) count to avoid zero probabilities. When the value added is 1, this is Laplace smoothing. When the value added is 0.5, this is Lidstone smoothing.

This implementation uses 0.5 as the adjustment value (Lidstone smoothing).

Field Summary

Fields

Modifier and Type	Field and Description
protected double	additiveAdjustmentValue Additive adjustment value = 0.5 (Lidstone smoothing).
protected boolean	debug True if debugging enabled.

Fields inherited from class edu.northwestern.at.morphadorner.corpuslinguistics.postagger.smoothing.lexical.AbstractLexicalSmoother

cachedLexicalProbabilities, logger, partOfSpeechTagger

Constructor Summary

Constructors

Constructor and Description
AdditiveLexicalSmoother() Create an additive lexical smoother.

Method Summary

Methods

Modifier and Type	Method and Description
Probability	lexicalProbability(java.lang.String word, java.lang.String tag) Get lexically smoothed probability of a word given a tag.

Methods inherited from class edu.northwestern.at.morphadorner.corpuslinguistics.postagger.smoothing.lexical.AbstractLexicalSmoother

cachedProbabilitiesCount, clearCachedProbabilities, getLogger, setLogger, setPartOfSpeechTagger

Methods inherited from class edu.northwestern.at.utils.IsCloseableObject

close

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.northwestern.at.morphadorner.corpuslinguistics.postagger.smoothing.lexical.LexicalSmoother

cachedProbabilitiesCount, clearCachedProbabilities, setPartOfSpeechTagger

Field Detail

debug

protected boolean debug

True if debugging enabled.

additiveAdjustmentValue

protected double additiveAdjustmentValue

Additive adjustment value = 0.5 (Lidstone smoothing).

Constructor Detail

AdditiveLexicalSmoother

public AdditiveLexicalSmoother()

Create an additive lexical smoother.

Method Detail

lexicalProbability

public Probability lexicalProbability(java.lang.String word,
                             java.lang.String tag)

Get lexically smoothed probability of a word given a tag.

Specified by:

lexicalProbability in interface LexicalSmoother

Specified by:

lexicalProbability in class AbstractLexicalSmoother

Parameters:

word - The word.

tag - The part of speech tag.

Returns:

Lexically smoothed probability of word given tag, e.g., p( word | tag ).