org.terrier.matching.models.aftereffect
Class LL

java.lang.Object
  extended by org.terrier.matching.models.aftereffect.AfterEffect
      extended by org.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.

Author:
Ben He
See Also:
Serialized Form

Field Summary
protected  java.lang.String methodName
          The name of the model.
 
Fields inherited from class org.terrier.matching.models.aftereffect.AfterEffect
avl, parameter
 
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 org.terrier.matching.models.aftereffect.AfterEffect
getParameter, setAverageDocumentLength, setParameter
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

methodName

protected final java.lang.String methodName
The name of the model.

See Also:
Constant Field Values
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.


Terrier 3.5. Copyright © 2004-2011 University of Glasgow