edu.illinois.cs.cogcomp.lbjava.classify

Class DiscreteFeature

java.lang.Object

edu.illinois.cs.cogcomp.lbjava.classify.Feature

edu.illinois.cs.cogcomp.lbjava.classify.DiscreteFeature

All Implemented Interfaces:

Serializable, Cloneable, Comparable

Direct Known Subclasses:

DiscreteConjunctiveFeature, DiscretePrimitiveFeature, DiscretePrimitiveStringFeature, DiscreteReferrer

public abstract class DiscreteFeature
extends Feature

A discrete feature takes on one value from a set of discontinuous values. The set of values that a given DiscreteFeature may take is defined in the Classifier that produced the feature.

Author:

Nick Rizzolo

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String[]	BooleanValues Convient access to a common allowable value set.
protected short	totalValues The total number of allowable values for this feature.
protected short	valueIndex Index into the set of allowable values corresponding to this value.

Fields inherited from class edu.illinois.cs.cogcomp.lbjava.classify.Feature

containingPackage, generatingClassifier

Method Summary

Modifier and Type	Method and Description
Feature	conjunction(Feature f, Classifier c) Create a feature representing the conjunction of this feature with the given argument feature.
protected Feature	conjunctWith(DiscreteFeature f, Classifier c) Create a feature representing the conjunction of this feature with the given argument feature.
double	getStrength() Returns the strength of this feature if it were to be placed in a mathematical vector space.
short	getValueIndex() Returns the index in the generating classifier's value list of this feature's value.
boolean	isDiscrete() Determines if this feature is discrete.
void	lexRead(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessInputStream in, Lexicon lex, String p, String g, String si, ByteString bi) Reads the representation of a feature with this object's run-time type as stored by a lexicon, overwriting the data in this object.
String	lexWrite(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessOutputStream out, Lexicon lex, String c, String p, String g, String si, ByteString bi) Writes a binary representation of the feature intended for use by a lexicon, omitting redundant information when possible.
void	read(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessInputStream in) Reads the representation of a feaeture with this object's run-time type from the given stream, overwriting the data in this object.
short	totalValues() Returns the total number of values this feature might possibly be set to.
void	write(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessOutputStream out) Writes a complete binary representation of the feature.

Methods inherited from class edu.illinois.cs.cogcomp.lbjava.classify.Feature

childLexiconLookup, classEquivalent, clone, compareNameStrings, compareTo, conjunctWith, depth, encode, equals, fromArray, getByteStringIdentifier, getByteStringValue, getFeatureKey, getFeatureKey, getGeneratingClassifier, getPackage, getStringIdentifier, getStringValue, hasByteStringIdentifier, hashCode, hasStringIdentifier, isConjunctive, isPrimitive, isReferrer, lexReadFeature, makeReal, readFeature, removeFromChildLexicon, setArrayLength, toString, toStringNoPackage, valueEquals, withStrength, write, writeNameString, writeNoPackage

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

BooleanValues

public static final String[] BooleanValues

Convient access to a common allowable value set.

valueIndex

protected short valueIndex

Index into the set of allowable values corresponding to this value.

totalValues

protected short totalValues

The total number of allowable values for this feature.

Method Detail

isDiscrete

public boolean isDiscrete()

Determines if this feature is discrete.

Specified by:

isDiscrete in class Feature

Returns:

true iff this is discrete.

getValueIndex

public short getValueIndex()

Returns the index in the generating classifier's value list of this feature's value.

Overrides:

getValueIndex in class Feature

Returns:

A non-negative integer index, or -1 if this feature doesn't have a value list.

totalValues

public short totalValues()

Returns the total number of values this feature might possibly be set to.

Overrides:

totalValues in class Feature

Returns:

Some integer greater than 1 iff this feature is a discrete feature with a specified value list, and 0 otherwise.

getStrength

public double getStrength()

Returns the strength of this feature if it were to be placed in a mathematical vector space.

Specified by:

getStrength in class Feature

conjunction

public Feature conjunction(Feature f,
                           Classifier c)

Create a feature representing the conjunction of this feature with the given argument feature.

Specified by:

conjunction in class Feature

Parameters:

f - The feature to conjunct with.

c - The classifier producing the resulting feature.

Returns:

A feature representing the conjunction of this feature and f.

conjunctWith

protected Feature conjunctWith(DiscreteFeature f,
                               Classifier c)

Create a feature representing the conjunction of this feature with the given argument feature.

Overrides:

conjunctWith in class Feature

Parameters:

f - The feature to conjunct with.

c - The classifier producing the resulting feature.

Returns:

A feature representing the conjunction of this feature and f.

write

public void write(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessOutputStream out)

Writes a complete binary representation of the feature.

Overrides:

write in class Feature

Parameters:

out - The output stream.

read

public void read(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessInputStream in)

Reads the representation of a feaeture with this object's run-time type from the given stream, overwriting the data in this object.

Overrides:

read in class Feature

Parameters:

in - The input stream.

lexWrite

public String lexWrite(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessOutputStream out,
                       Lexicon lex,
                       String c,
                       String p,
                       String g,
                       String si,
                       ByteString bi)

Writes a binary representation of the feature intended for use by a lexicon, omitting redundant information when possible.

Overrides:

lexWrite in class Feature

Parameters:

out - The output stream.

lex - The lexicon out of which this feature is being written.

c - The fully qualified name of the assumed class. The runtime class of this feature won't be written if it's equivalent to c.

p - The assumed package string. This feature's package string won't be written if it's equivalent to p.

g - The assumed classifier name string. This feature's classifier name string won't be written if it's equivalent to g.

si - The assumed identifier as a string. If this feature has a string identifier, it won't be written if it's equivalent to si.

bi - The assumed identifier as a byte string. If this feature has a byte string identifier, it won't be written if it's equivalent to bi.

Returns:

The name of the runtime type of this feature.

lexRead

public void lexRead(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessInputStream in,
                    Lexicon lex,
                    String p,
                    String g,
                    String si,
                    ByteString bi)

Reads the representation of a feature with this object's run-time type as stored by a lexicon, overwriting the data in this object.

This method is appropriate for reading features as written by lexWrite(ExceptionlessOutputStream,Lexicon,String,String,String,String,ByteString).

Overrides:

lexRead in class Feature

Parameters:

in - The input stream.

lex - The lexicon we are reading in to.

p - The assumed package string. If no package name is given in the input stream, the instantiated feature is given this package.

g - The assumed classifier name string. If no classifier name is given in the input stream, the instantiated feature is given this classifier name.

si - The assumed identifier as a string. If the feature being read has a string identifier field and no identifier is given in the input stream, the feature is given this identifier.

bi - The assumed identifier as a byte string. If the feature being read has a byte string identifier field and no identifier is given in the input stream, the feature is given this identifier.