org.terrier.matching.models.normalisation

Class NormalisationStatic

java.lang.Object

org.terrier.matching.models.normalisation.Normalisation

org.terrier.matching.models.normalisation.NormalisationStatic

All Implemented Interfaces:

Serializable, Cloneable

public class NormalisationStatic
extends Normalisation

This class implements a Normalisation method that forces all term frequencies to the value of the parameter. If field retrieval is enabled, then the parameter is multiplied by the field weight.

Author:

Craig Macdonald

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected String	methodName The name of the normalisation method .

Fields inherited from class org.terrier.matching.models.normalisation.Normalisation

averageDocumentLength, idf, Nt, numberOfDocuments, numberOfTokens, parameter, termFrequency

Constructor Summary

Constructors

Constructor and Description
NormalisationStatic()

Method Summary

Methods

Modifier and Type	Method and Description
String	getInfo() Get the name of the normalisation method.
double	normalise(double tf, double docLength, double termFrequency) Returns a static term frequency.

Methods inherited from class org.terrier.matching.models.normalisation.Normalisation

clone, getParameter, setAverageDocumentLength, setDocumentFrequency, setNumberOfDocuments, setNumberOfTokens, setParameter

Methods inherited from class java.lang.Object

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

Field Detail

methodName

protected final String methodName

The name of the normalisation method .

See Also:

Constant Field Values

Constructor Detail

NormalisationStatic

public NormalisationStatic()

Method Detail

getInfo

public String getInfo()

Get the name of the normalisation method.

Specified by:

getInfo in class Normalisation

Returns:

Return the name of the normalisation method.

normalise

public double normalise(double tf,
               double docLength,
               double termFrequency)

Returns a static term frequency. i.e. tf = (tf > 0) ? parameter : 0

Specified by:

normalise in class Normalisation

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.