org.terrier.matching.models.normalisation

Class Normalisation2exp

java.lang.Object

org.terrier.matching.models.normalisation.Normalisation

org.terrier.matching.models.normalisation.Normalisation2exp

All Implemented Interfaces:

Serializable, Cloneable

public class Normalisation2exp
extends Normalisation

This class implements the DFR normalisation 2 with natural logorithm.

Author:

Ben He

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
Normalisation2exp() The default constructor.

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) This method gets the normalised 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

Normalisation2exp

public Normalisation2exp()

The default constructor. The hyper-parameter value is set to 1.0 by default.

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)

This method gets the normalised term frequency.

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.