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 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

WARNING: This API is experimental and might change in incompatible ways in the next release.

Nested Class Summary

static class

AfterEffect.NoAfterEffect Implementation used when there is no aftereffect.

Constructor Summary

AfterEffect()
Sole constructor.

Method Summary

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 String	toString() Subclasses must override this method to return the code of the after effect formula.

Methods inherited from class java.lang.Object

clone, equals, finalize, 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 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 Object