Class BasicModelD

Implements the approximation of the binomial model with the divergence for DFR. The formula used in Lucene differs slightly from the one in the original paper: to avoid underflow for small values of N and F, N is increased by 1 and F is always increased by tfn+1.

WARNING: for terms that do not meet the expected random distribution (e.g. stopwords), this model may give poor performance, such as abnormally high scores for low tf values.

Note

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

Inheritance

object

BasicModel

BasicModelD

Inherited Members

BasicModel.Explain(BasicStats, float)

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

Namespace: Lucene.Net.Search.Similarities

Assembly: Lucene.Net.dll

Syntax

public class BasicModelD : BasicModel

Constructors

BasicModelD()

Sole constructor: parameter-free

Declaration

public BasicModelD()

Methods

Score(BasicStats, float)

Returns the informative content score.

Declaration

public override sealed float Score(BasicStats stats, float tfn)

Parameters

Type	Name	Description
BasicStats	stats
float	tfn

Returns

Type	Description
float

Overrides

BasicModel.Score(BasicStats, float)

ToString()

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

Declaration

public override string ToString()

Returns

Type	Description
string

Overrides

BasicModel.ToString()