edu.ucla.sspace.wordsi

Class AbstractOccurrenceDependencyContextGenerator

java.lang.Object

edu.ucla.sspace.wordsi.AbstractOccurrenceDependencyContextGenerator

All Implemented Interfaces:

DependencyContextGenerator

Direct Known Subclasses:

OccurrenceDependencyContextGenerator, OrderingDependencyContextGenerator, PartOfSpeechDependencyContextGenerator

public abstract class AbstractOccurrenceDependencyContextGenerator
extends Object
implements DependencyContextGenerator

An abstract DependencyContextGenerator that creates a context vector for a node in an array of DependencyTreeNodes by using any form of co-occurrence information in the tree. The windowSize words prior to the focus word will be marked as having a negative index with respect to the focus word and the words after the focus word will be marked with a positive index. Subclasses need only implement getFeature.

Author:

Keith Stevens

Constructor Summary

Constructors

Constructor and Description
AbstractOccurrenceDependencyContextGenerator(BasisMapping<String,String> basis, int windowSize) Constructs a new AbstractOccurrenceDependencyContextGenerator.

Method Summary

Methods

Modifier and Type	Method and Description
protected void	addContextTerms(SparseDoubleVector meaning, Queue<String> words, int distance) Adds a feature for each word in the context that has a valid dimension.
SparseDoubleVector	generateContext(DependencyTreeNode[] tree, int focusIndex) Returns a SparseDoubleVector that represents the context composed of the set of prevWords before the focus word and the set of nextWords after the focus word.
protected abstract String	getFeature(DependencyTreeNode node, int dist) Returns a string representing the DependencyTreeNode which is dist nodes away from the focus word currently being processed.
int	getVectorLength() Returns the maximum number of dimensions used to represent any given context.
void	setReadOnly(boolean readOnly) Sets the read only mode of the ContextGenerator.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractOccurrenceDependencyContextGenerator

public AbstractOccurrenceDependencyContextGenerator(BasisMapping<String,String> basis,
                                            int windowSize)

Constructs a new AbstractOccurrenceDependencyContextGenerator.

Method Detail

generateContext

public SparseDoubleVector generateContext(DependencyTreeNode[] tree,
                                 int focusIndex)

Returns a SparseDoubleVector that represents the context composed of the set of prevWords before the focus word and the set of nextWords after the focus word. Since sparse vectors are returned, if a second order vector is generated, it is recommended that the vector also be sparsed or have very few dimensions.

Specified by:

generateContext in interface DependencyContextGenerator

getFeature

protected abstract String getFeature(DependencyTreeNode node,
                int dist)

Returns a string representing the DependencyTreeNode which is dist nodes away from the focus word currently being processed.

addContextTerms

protected void addContextTerms(SparseDoubleVector meaning,
                   Queue<String> words,
                   int distance)

Adds a feature for each word in the context that has a valid dimension. Feature are scored based on the context word's distance from the focus word.

getVectorLength

public int getVectorLength()

Returns the maximum number of dimensions used to represent any given context.

Specified by:

getVectorLength in interface DependencyContextGenerator

setReadOnly

public void setReadOnly(boolean readOnly)

Sets the read only mode of the ContextGenerator. When set to read only, it prevents any new features from being generated.

Specified by:

setReadOnly in interface DependencyContextGenerator