Package org.terrier.matching.models

Class Null

java.lang.Object

org.terrier.matching.models.WeightingModel

org.terrier.matching.models.Null

All Implemented Interfaces:

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

public class Null
extends WeightingModel

A weighting model that returns 0 for each match.

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
Null()

Method Summary

Modifier and Type	Method	Description
java.lang.String	getInfo()	Returns the name of the model.
double	score(double tf, double docLength)	This method provides the contract for implementing weighting models.

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

Null

public Null()

Method Detail

getInfo

public 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 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