org.apache.lucene.search.similarities

Class Independence

java.lang.Object

org.apache.lucene.search.similarities.Independence

Direct Known Subclasses:

IndependenceChiSquared, IndependenceSaturated, IndependenceStandardized

public abstract class Independence
extends java.lang.Object

Computes the measure of divergence from independence for DFI scoring functions.

See http://trec.nist.gov/pubs/trec21/papers/irra.web.nb.pdf for more information on different methods.

Constructor Summary

Constructors

Constructor and Description
Independence() Sole constructor.

Method Summary

Modifier and Type	Method and Description
abstract float	score(float freq, float expected) Computes distance from independence
abstract java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

Independence

public Independence()

Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail

score

public abstract float score(float freq,
                            float expected)

Computes distance from independence

Parameters:

freq - actual term frequency

expected - expected term frequency

toString

public abstract java.lang.String toString()

Overrides:

toString in class java.lang.Object