uk.ac.gla.terrier.matching.models.normalisation
Class Normalisation

java.lang.Object
  uk.ac.gla.terrier.matching.models.normalisation.Normalisation

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

Normalisation0, Normalisation2, Normalisation2exp, Normalisation3, NormalisationB, NormalisationStatic

public abstract class Normalisation
extends java.lang.Object
implements java.io.Serializable

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.

Version:

$Revision: 1.11 $

Author:

Ben He

See Also:

Serialized Form

Constructor Summary

Normalisation()
The default constructor.

Normalisation(double value)
The constructor that specifies the parameter value.

Method Summary

void	disableFieldRetrieval()
void	enableFieldRetrieval()
double	getFieldWeight() Returns the weight of the field for field retrieval.
abstract java.lang.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	setFieldWeight(double value) This method sets the weight of a field.
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, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

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

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.

setFieldWeight

public void setFieldWeight(double value)

This method sets the weight of a field. The final normalised frequency is the product of the normalised frequency with the weight.

Parameters:

value - The weight of the field.

enableFieldRetrieval

public void enableFieldRetrieval()

disableFieldRetrieval

public void disableFieldRetrieval()

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.

getFieldWeight

public double getFieldWeight()

Returns the weight of the field for field retrieval.

Returns:

The weight of the field.

getParameter

public double getParameter()

Returns the hyper-parameter value.

Returns:

The hyper-parameter value.

getInfo

public abstract java.lang.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