Package org.apache.lucene.search.similarities

Class BasicModel

java.lang.Object

org.apache.lucene.search.similarities.BasicModel

Direct Known Subclasses:

BasicModelG, BasicModelIF, BasicModelIn, BasicModelIne

public abstract class BasicModel
extends Object

This class acts as the base class for the specific basic model implementations in the DFR framework. Basic models compute the informative content Inf₁ = -log₂Prob₁ .

See Also:

• DFRSimilarity

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

Constructor Summary

Constructors

Constructor	Description
BasicModel()	Sole constructor.

Method Summary

Modifier and Type	Method	Description
abstract Explanation	explain(BasicStats stats, double tfn, double aeTimes1pTfn)	Returns an explanation for the score.
abstract double	score(BasicStats stats, double tfn, double aeTimes1pTfn)	Returns the informative content score combined with the after effect, more specifically informationContentScore * aeTimes1pTfn / (1 + tfn).
abstract String	toString()	Subclasses must override this method to return the code of the basic model formula.

Methods inherited from class java.lang.Object

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

Constructor Details

BasicModel

public BasicModel()

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

Method Details

score

public abstract double score(BasicStats stats,
 double tfn,
 double aeTimes1pTfn)

Returns the informative content score combined with the after effect, more specifically informationContentScore * aeTimes1pTfn / (1 + tfn). This function must be non-decreasing with tfn.

explain

public abstract Explanation explain(BasicStats stats,
 double tfn,
 double aeTimes1pTfn)

Returns an explanation for the score. Subclasses must override this method.

toString

public abstract String toString()

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

Overrides:

toString in class Object