edu.illinois.cs.cogcomp.lbjava.classify

Class RealConjunctiveFeature

java.lang.Object

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

edu.illinois.cs.cogcomp.lbjava.classify.RealFeature

edu.illinois.cs.cogcomp.lbjava.classify.RealConjunctiveFeature

All Implemented Interfaces:

Serializable, Cloneable, Comparable

public class RealConjunctiveFeature
extends RealFeature

Represents the conjunction of two features.

Author:

Nick Rizzolo

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected Feature	left One feature argument.
protected Feature	right The other feature argument.

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

containingPackage, generatingClassifier

Constructor Summary

Constructors

Constructor and Description
RealConjunctiveFeature() For internal use only.
RealConjunctiveFeature(Classifier c, Feature l, Feature r) Creates a new conjunctive feature taking the package and name of the given classifier.
RealConjunctiveFeature(String p, String c, Feature l, Feature r) Creates a new conjunctive feature.

Method Summary

Modifier and Type	Method and Description
int	childLexiconLookup(ChildLexicon lex, int label) Does a feature-type-specific lookup of this feature in the given ChildLexicon.
int	compareTo(Object o) Used to sort features into an order that is convenient both to page through and for the lexicon to read off disk.
int	depth() The depth of a feature is one more than the maximum depth of any of its children, or 0 if it has no children.
Feature	encode(String e) Returns a feature object in which any strings that are being used to represent an identifier or value have been encoded in byte strings.
boolean	equals(Object o) Two conjunctions are equivalent when their arguments are equivalent.
protected Feature	getArgumentKey(Feature f, Lexicon lexicon, boolean training, int label) A helper method for getFeatureKey(Lexicon,boolean,int), this method computes the feature keys corresponding to the arguments of the conjunction.
ByteString	getByteStringIdentifier() Retrieves this feature's identifier as a byte string.
Feature	getFeatureKey(Lexicon lexicon, boolean training, int label) Return the feature that should be used to index this feature into a lexicon.
Feature	getLeft() Returns the value of left.
Feature	getRight() Returns the value of right.
double	getStrength() Returns the strength of this feature if it were to be placed in a mathematical vector space.
String	getStringIdentifier() Retrieves this feature's identifier as a string.
int	hashCode() Returns a hash code based on the hash codes of left and right.
boolean	isConjunctive() Determines if this feature is conjunctive.
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.
RealFeature	multiply(double m) Returns a new feature object, the same as this one in all respects except the value has been multiplied by the specified number.
void	read(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessInputStream in) Reads the representation of a feature with this object's run-time type from the given stream, overwriting the data in this object.
void	removeFromChildLexicon(ChildLexicon lex) Takes care of any feature-type-specific tasks that need to be taken care of when removing a feature of this type from a ChildLexicon, in particular updating parent counts and removing children of this feature if necessary.
Feature	withStrength(double s) Returns a new feature object that's identical to this feature except its strength is given by s.
void	write(edu.illinois.cs.cogcomp.core.datastructures.vectors.ExceptionlessOutputStream out) Writes a complete binary representation of the feature.
void	write(StringBuffer buffer) Writes a string representation of this Feature to the specified buffer.
void	writeNoPackage(StringBuffer buffer) Writes a string representation of this Feature to the specified buffer, omitting the package name.

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

conjunction, getByteStringValue, getStringValue, isDiscrete, makeReal, valueEquals

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

classEquivalent, clone, compareNameStrings, conjunctWith, conjunctWith, fromArray, getFeatureKey, getGeneratingClassifier, getPackage, getValueIndex, hasByteStringIdentifier, hasStringIdentifier, isPrimitive, isReferrer, lexReadFeature, readFeature, setArrayLength, toString, toStringNoPackage, totalValues, writeNameString

Methods inherited from class java.lang.Object

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

Field Detail

left

protected Feature left

One feature argument.

right

protected Feature right

The other feature argument.

Constructor Detail

RealConjunctiveFeature

public RealConjunctiveFeature()

For internal use only.

See Also:

Feature.readFeature(ExceptionlessInputStream)

RealConjunctiveFeature

public RealConjunctiveFeature(Classifier c,
                              Feature l,
                              Feature r)

Creates a new conjunctive feature taking the package and name of the given classifier.

Parameters:

c - The classifier from which package and name information is taken.

l - One feature argument.

r - The other feature argument.

RealConjunctiveFeature

public RealConjunctiveFeature(String p,
                              String c,
                              Feature l,
                              Feature r)

Creates a new conjunctive feature.

Parameters:

p - The new discrete feature's package.

c - The name of the classifier that produced this feature.

l - One feature argument.

r - The other feature argument.

Method Detail

isConjunctive

public boolean isConjunctive()

Determines if this feature is conjunctive.

Overrides:

isConjunctive in class Feature

Returns:

true iff this feature is conjunctive.

getLeft

public Feature getLeft()

Returns the value of left.

getRight

public Feature getRight()

Returns the value of right.

getStringIdentifier

public String getStringIdentifier()

Retrieves this feature's identifier as a string.

Specified by:

getStringIdentifier in class Feature

Returns:

The empty string, since conjunctive features don't have identifiers.

getByteStringIdentifier

public ByteString getByteStringIdentifier()

Retrieves this feature's identifier as a byte string.

Specified by:

getByteStringIdentifier in class Feature

Returns:

ByteString.emptyString, since conjunctive features don't have identifiers.

depth

public int depth()

The depth of a feature is one more than the maximum depth of any of its children, or 0 if it has no children.

Overrides:

depth in class Feature

Returns:

The depth of this feature as described above.

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

getFeatureKey

public Feature getFeatureKey(Lexicon lexicon,
                             boolean training,
                             int label)

Return the feature that should be used to index this feature into a lexicon.

Specified by:

getFeatureKey in class Feature

Parameters:

lexicon - The lexicon into which this feature will be indexed.

training - Whether or not the learner is currently training.

label - The label of the example containing this feature, or -1 if we aren't doing per class feature counting.

Returns:

A feature object appropriate for use as the key of a map.

getArgumentKey

protected Feature getArgumentKey(Feature f,
                                 Lexicon lexicon,
                                 boolean training,
                                 int label)

A helper method for getFeatureKey(Lexicon,boolean,int), this method computes the feature keys corresponding to the arguments of the conjunction. Here, we lookup the arguments to the conjunction in the lexicon so that their counts are never less than the conjunction's, and we return the actual feature object that's already a key in the lexicon.

Parameters:

f - The argument feature for which a key will be computed.

lexicon - The lexicon into which this feature will be indexed.

training - Whether or not the learner is currently training.

label - The label of the example containing this feature, or -1 if we aren't doing per class feature counting.

Returns:

A feature object appropriate for use as the key of a map.

multiply

public RealFeature multiply(double m)

Returns a new feature object, the same as this one in all respects except the value has been multiplied by the specified number.

Specified by:

multiply in class RealFeature

Parameters:

m - The multiplier.

Returns:

A new real feature whose value is the product of this feature's value and the specified multiplier.

withStrength

public Feature withStrength(double s)

Returns a new feature object that's identical to this feature except its strength is given by s.

Specified by:

withStrength in class Feature

Parameters:

s - The strength of the new feature.

Returns:

A new feature object as above, or null if this feature cannot take the specified strength.

encode

public Feature encode(String e)

Returns a feature object in which any strings that are being used to represent an identifier or value have been encoded in byte strings.

Specified by:

encode in class Feature

Parameters:

e - The encoding to use.

Returns:

A feature object as above; possible this object.

removeFromChildLexicon

public void removeFromChildLexicon(ChildLexicon lex)

Takes care of any feature-type-specific tasks that need to be taken care of when removing a feature of this type from a ChildLexicon, in particular updating parent counts and removing children of this feature if necessary.

Overrides:

removeFromChildLexicon in class Feature

Parameters:

lex - The child lexicon this feature is being removed from.

childLexiconLookup

public int childLexiconLookup(ChildLexicon lex,
                              int label)

Does a feature-type-specific lookup of this feature in the given ChildLexicon.

Overrides:

childLexiconLookup in class Feature

Parameters:

lex - The child lexicon this feature is being looked up in.

label - The label of the example containing this feature, or -1 if we aren't doing per class feature counting.

Returns:

The index of f in this lexicon.

hashCode

public int hashCode()

Returns a hash code based on the hash codes of left and right.

Overrides:

hashCode in class Feature

Returns:

The hash code of this feature.

equals

public boolean equals(Object o)

Two conjunctions are equivalent when their arguments are equivalent.

Overrides:

equals in class Feature

Returns:

true iff the argument is an equivalent Feature.

compareTo

public int compareTo(Object o)

Used to sort features into an order that is convenient both to page through and for the lexicon to read off disk.

Specified by:

compareTo in interface Comparable

Specified by:

compareTo in class Feature

Parameters:

o - An object to compare with.

Returns:

Integers appropriate for sorting features first by left and then by right.

write

public void write(StringBuffer buffer)

Writes a string representation of this Feature to the specified buffer.

Specified by:

write in class Feature

Parameters:

buffer - The buffer to write to.

writeNoPackage

public void writeNoPackage(StringBuffer buffer)

Writes a string representation of this Feature to the specified buffer, omitting the package name.

Overrides:

writeNoPackage in class Feature

Parameters:

buffer - The buffer to write to.

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 feature with this object's run-time type from the given stream, overwriting the data in this object.

This method is appropriate for reading features as written by write(ExceptionlessOutputStream).

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.