org.terrier.matching.models.normalisation

Class Normalisation

java.lang.Object

org.terrier.matching.models.normalisation.Normalisation

All Implemented Interfaces:

Serializable, Cloneable

Direct Known Subclasses:

Normalisation0, Normalisation1, Normalisation2, Normalisation2exp, Normalisation3, NormalisationB, NormalisationF, NormalisationJ, NormalisationJN, NormalisationP, NormalisationStatic

public abstract class Normalisation
extends Object
implements Serializable, Cloneable

This class provides a contract for implementing frequency normalisation methods. Properties

• field.retrieval - A boolean variable that indicates if field-retrieval is enabled. This allows for further extension with retrieval over different fields.

Author:

Ben He

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected double	averageDocumentLength The average document length in the collection.
protected Idf	idf The class used for computing the logorithm values.
protected double	Nt The document frequency of the term.
protected double	numberOfDocuments The number of documents in the whole collection.
protected double	numberOfTokens The number of tokens in the whole collection.
protected double	parameter The free parameter of the normalisation method.
protected double	termFrequency The frequency of the query term in the whole collection.

Constructor Summary

Constructors

Constructor and Description
Normalisation() The default constructor.
Normalisation(double value) The constructor that specifies the parameter value.

Method Summary

Methods

Modifier and Type	Method and Description
Normalisation	clone() Clone this weighting model
abstract String	getInfo() This method provides the contract for getting the name of the implemented frequency normalisation method.
double	getParameter() Returns the hyper-parameter value.
abstract double	normalise(double tf, double docLength, double _termFrequency) This method provides the contract for implementing the frequency normalisation formula.
void	setAverageDocumentLength(double value) Set the average document length in the collection.
void	setDocumentFrequency(double nt)
void	setNumberOfDocuments(double _numberOfDocuments)
void	setNumberOfTokens(double value) Set the number of tokens in the collection.
void	setParameter(double value) Specify the free parameter of the implemented frequency normalisation method.

Methods inherited from class java.lang.Object

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

Field Detail

averageDocumentLength

protected double averageDocumentLength

The average document length in the collection.

idf

protected Idf idf

The class used for computing the logorithm values.

termFrequency

protected double termFrequency

The frequency of the query term in the whole collection.

parameter

protected double parameter

The free parameter of the normalisation method.

numberOfTokens

protected double numberOfTokens

The number of tokens in the whole collection.

Nt

protected double Nt

The document frequency of the term.

numberOfDocuments

protected double numberOfDocuments

The number of documents in the whole collection.

Constructor Detail

Normalisation

public Normalisation()

The default constructor.

Normalisation

public Normalisation(double value)

The constructor that specifies the parameter value.

Parameters:

value - The specified value of the free parameter of the implemented frequency normalisation method.

Method Detail

clone

public Normalisation clone()

Clone this weighting model

Overrides:

clone in class Object

setAverageDocumentLength

public void setAverageDocumentLength(double value)

Set the average document length in the collection.

Parameters:

value - The average document length in the collection.

setNumberOfTokens

public void setNumberOfTokens(double value)

Set the number of tokens in the collection.

Parameters:

value - The number of tokens in the collection.

setParameter

public void setParameter(double value)

Specify the free parameter of the implemented frequency normalisation method.

Parameters:

value - The specified value of the frequency normalisation parameter.

getParameter

public double getParameter()

Returns the hyper-parameter value.

Returns:

The hyper-parameter value.

getInfo

public abstract String getInfo()

This method provides the contract for getting the name of the implemented frequency normalisation method.

Returns:

The name of the implemented frequency normalisation method.

normalise

public abstract double normalise(double tf,
               double docLength,
               double _termFrequency)

This method provides the contract for implementing the frequency normalisation formula.

Parameters:

tf - The frequency of the query term in the document.

docLength - The number of tokens in the document.

_termFrequency - The frequency of the query term in the collection.

Returns:

The normalised term frequency.

setDocumentFrequency

public void setDocumentFrequency(double nt)

Parameters:

nt - the document frequency to set

setNumberOfDocuments

public void setNumberOfDocuments(double _numberOfDocuments)

Parameters:

_numberOfDocuments - the numberOfDocuments to set