Class NormalisationJN

  extended by org.terrier.matching.models.normalisation.Normalisation
      extended by org.terrier.matching.models.normalisation.NormalisationJN
All Implemented Interfaces:

public class NormalisationJN
extends Normalisation

This class implements the tf normalisation based on Jelinek-Mercer smoothing for language modelling where collection model is given by document frequency instead of term frequency.

Ben He
See Also:
Serialized Form

Field Summary
protected  java.lang.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
Method Summary
 java.lang.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
getParameter, setAverageDocumentLength, setDocumentFrequency, setNumberOfDocuments, setNumberOfTokens, setParameter
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail


protected final java.lang.String methodName
The name of the normalisation method .

See Also:
Constant Field Values
Constructor Detail


public NormalisationJN()
Method Detail


public java.lang.String getInfo()
Get the name of the normalisation method.

Specified by:
getInfo in class Normalisation
Return the name of the normalisation method.


public double normalise(double tf,
                        double docLength,
                        double termFrequency)
This method gets the normalised term frequency.

Specified by:
normalise in class Normalisation
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.
The normalised term frequency.

Terrier 3.5. Copyright © 2004-2011 University of Glasgow