uk.ac.gla.terrier.matching.models.aftereffect
Class LL

java.lang.Object
  uk.ac.gla.terrier.matching.models.aftereffect.AfterEffect
      uk.ac.gla.terrier.matching.models.aftereffect.LL

All Implemented Interfaces:

java.io.Serializable

public class LL
extends AfterEffect

This class implements the LL model for the first normalisation by after effect. LL stands for the log of laplace succession.

Version:

$Revision: 1.7 $

Author:

Ben He

See Also:

Serialized Form

Constructor Summary

LL()
The default constructor.

Method Summary

double	gain(double tf, double documentFrequency, double termFrequency) This method computes the gain of encountering an extra token of the query term.
java.lang.String	getInfo() Returns the name of the method.

Methods inherited from class uk.ac.gla.terrier.matching.models.aftereffect.AfterEffect

getParameter, setAverageDocumentLength, setParameter

Methods inherited from class java.lang.Object

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

Constructor Detail

LL

public LL()

The default constructor.

Method Detail

getInfo

public java.lang.String getInfo()

Returns the name of the method.

Specified by:

getInfo in class AfterEffect

Returns:

The name of the method.

gain

public double gain(double tf,
                   double documentFrequency,
                   double termFrequency)

This method computes the gain of encountering an extra token of the query term.

Specified by:

gain in class AfterEffect

Parameters:

tf - The term frequency in the document

documentFrequency - The document frequency of the term

termFrequency - the term frequency in the collection

Returns:

the gain returned by the implemented formula.