Package org.terrier.matching.models

Class Dl

java.lang.Object

org.terrier.matching.models.WeightingModel

org.terrier.matching.models.Dl

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, Model

public class Dl
extends WeightingModel

This class implements a simple document length weighting model.

Since:

4.0

Author:

Craig Macdonald

See Also:

Serialized Form

Field Summary

Fields inherited from class org.terrier.matching.models.WeightingModel

averageDocumentLength, c, cs, documentFrequency, es, i, keyFrequency, numberOfDocuments, numberOfPointers, numberOfPostings, numberOfTokens, numberOfUniqueTerms, rq, termFrequency

Constructor Summary

Constructors

Constructor	Description
Dl()
Dl(double b)

Method Summary

Modifier and Type	Method	Description
java.lang.String	getInfo()	Returns the name of the model.
double	getParameter()	Returns the b parameter to the ranking formula as set by setParameter()
double	score(double tf, double docLength)	This method provides the contract for implementing weighting models.
void	setParameter(double b)	Sets the b parameter to ranking formula

Methods inherited from class org.terrier.matching.models.WeightingModel

clone, getOverflowed, prepare, score, setCollectionStatistics, setEntryStatistics, setKeyFrequency, setRequest

Methods inherited from class java.lang.Object

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

Constructor Detail

Dl

public Dl()

Dl

public Dl(double b)

Method Detail

getInfo

public final java.lang.String getInfo()

Description copied from class: WeightingModel

Returns the name of the model.

Specified by:

getInfo in interface Model

Specified by:

getInfo in class WeightingModel

Returns:

java.lang.String

score

public final double score(double tf,
                          double docLength)

Description copied from class: WeightingModel

This method provides the contract for implementing weighting models.

Specified by:

score in class WeightingModel

Parameters:

tf - The term frequency in the document

docLength - the document's length

Returns:

the score assigned to a document with the given tf and docLength, and other preset parameters

setParameter

public void setParameter(double b)

Sets the b parameter to ranking formula

Specified by:

setParameter in interface Model

Overrides:

setParameter in class WeightingModel

Parameters:

b - the b parameter value to use.

getParameter

public double getParameter()

Returns the b parameter to the ranking formula as set by setParameter()

Specified by:

getParameter in interface Model

Overrides:

getParameter in class WeightingModel