Package org.apache.lucene.search.similarities

Class AfterEffect

java.lang.Object

org.apache.lucene.search.similarities.AfterEffect

Direct Known Subclasses:

AfterEffect.NoAfterEffect, AfterEffectB, AfterEffectL

public abstract class AfterEffect
extends java.lang.Object

This class acts as the base class for the implementations of the first normalization of the informative content in the DFR framework. This component is also called the after effect and is defined by the formula Inf₂ = 1 - Prob₂, where Prob₂ measures the information gain.

See Also:

DFRSimilarity

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	AfterEffect.NoAfterEffect	Implementation used when there is no aftereffect.

Constructor Summary

Constructors

Constructor	Description
AfterEffect()	Sole constructor.

Method Summary

Modifier and Type	Method	Description
abstract Explanation	explain(BasicStats stats, float tfn)	Returns an explanation for the score.
abstract float	score(BasicStats stats, float tfn)	Returns the aftereffect score.
abstract java.lang.String	toString()	Subclasses must override this method to return the code of the after effect formula.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

AfterEffect

public AfterEffect()

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

Method Detail

score

public abstract float score(BasicStats stats,
                            float tfn)

Returns the aftereffect score.

explain

public abstract Explanation explain(BasicStats stats,
                                    float tfn)

Returns an explanation for the score.

toString

public abstract java.lang.String toString()

Subclasses must override this method to return the code of the after effect formula. Refer to the original paper for the list.

Overrides:

toString in class java.lang.Object