uk.ac.gla.terrier.matching.models
Class WeightingModel

java.lang.Object
  uk.ac.gla.terrier.matching.models.WeightingModel

All Implemented Interfaces:

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

Direct Known Subclasses:

BB2, BM25, DFR_BM25, DFRee, DFRWeightingModel, DLH, DLH13, Hiemstra_LM, IFB2, In_expB2, In_expC2, InL2, LemurTF_IDF, PL2, TF_IDF

public abstract class WeightingModel
extends java.lang.Object
implements Model, java.io.Serializable, java.lang.Cloneable

This class should be extended by the classes used for weighting terms and documents.

Version:

$Revision: 1.30 $

Author:

Gianni Amati, Ben He, Vassilis Plachouras

See Also:

Serialized Form

Constructor Summary

WeightingModel()
A default constructor that initialises the idf i attribute

Method Summary

java.lang.Object	clone() Clone this weighting model
abstract java.lang.String	getInfo() Returns the name of the model.
double	getParameter() Returns the parameter as set by setParameter()
abstract double	score(double tf, double docLength) This method provides the contract for implementing weighting models.
abstract double	score(double tf, double docLength, double n_t, double F_t, double keyFrequency) This method provides the contract for implementing weighting models.
void	setAverageDocumentLength(double avgDocLength) Sets the average length of documents in the collection.
void	setDocumentFrequency(double docFreq) Sets the document frequency of the term in the collection.
void	setKeyFrequency(double keyFreq) Sets the term's frequency in the query.
void	setNumberOfDocuments(double numOfDocs) Sets the number of documents in the collection.
void	setNumberOfPointers(double number) Set the number of pointers in the collection.
void	setNumberOfTokens(double value) Set the number of tokens in the collection.
void	setNumberOfUniqueTerms(double number) Set the number of unique terms in the collection.
void	setParameter(double c) Sets the c value
void	setTermFrequency(double termFreq) Sets the term's frequency in the collection.
double	stirlingPower(double n, double m) This method provides the contract for implementing the Stirling formula for the power series.

Methods inherited from class java.lang.Object

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

Constructor Detail

WeightingModel

public WeightingModel()

A default constructor that initialises the idf i attribute

Method Detail

clone

public java.lang.Object clone()

Clone this weighting model

Overrides:

clone in class java.lang.Object

getInfo

public abstract java.lang.String getInfo()

Returns the name of the model.

Specified by:

getInfo in interface Model

Returns:

java.lang.String

score

public abstract double score(double tf,
                             double docLength)

This method provides the contract for implementing weighting models.

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

score

public abstract double score(double tf,
                             double docLength,
                             double n_t,
                             double F_t,
                             double keyFrequency)

This method provides the contract for implementing weighting models.

Parameters:

tf - The term frequency in the document

docLength - the document's length

n_t - The document frequency of the term

F_t - the term frequency in the collection

keyFrequency - the term frequency in the query

Returns:

the score returned by the implemented weighting model.

setAverageDocumentLength

public void setAverageDocumentLength(double avgDocLength)

Sets the average length of documents in the collection.

Specified by:

setAverageDocumentLength in interface Model

Parameters:

avgDocLength - The documents' average length.

setParameter

public void setParameter(double c)

Sets the c value

Specified by:

setParameter in interface Model

Parameters:

c - the term frequency normalisation parameter value.

getParameter

public double getParameter()

Returns the parameter as set by setParameter()

Specified by:

getParameter in interface Model

setDocumentFrequency

public void setDocumentFrequency(double docFreq)

Sets the document frequency of the term in the collection.

Parameters:

docFreq - the document frequency of the term in the collection.

setKeyFrequency

public void setKeyFrequency(double keyFreq)

Sets the term's frequency in the query.

Parameters:

keyFreq - the term's frequency in the query.

setNumberOfTokens

public void setNumberOfTokens(double value)

Set the number of tokens in the collection.

Specified by:

setNumberOfTokens in interface Model

Parameters:

value - The number of tokens in the collection.

setNumberOfDocuments

public void setNumberOfDocuments(double numOfDocs)

Sets the number of documents in the collection.

Specified by:

setNumberOfDocuments in interface Model

Parameters:

numOfDocs - the number of documents in the collection.

setTermFrequency

public void setTermFrequency(double termFreq)

Sets the term's frequency in the collection.

Parameters:

termFreq - the term's frequency in the collection.

setNumberOfUniqueTerms

public void setNumberOfUniqueTerms(double number)

Set the number of unique terms in the collection.

Specified by:

setNumberOfUniqueTerms in interface Model

Parameters:

number - double The number of unique terms in the collection.

setNumberOfPointers

public void setNumberOfPointers(double number)

Set the number of pointers in the collection.

Specified by:

setNumberOfPointers in interface Model

stirlingPower

public double stirlingPower(double n,
                            double m)

This method provides the contract for implementing the Stirling formula for the power series.

Parameters:

n - The parameter of the Stirling formula.

m - The parameter of the Stirling formula.

Returns:

the approximation of the power series