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SimpleKLDocModel Class Reference

Doc representation for simple KL divergence retrieval model. More...

#include <SimpleKLDocModel.hpp>

Inheritance diagram for SimpleKLDocModel:

DocumentRep AbsoluteDiscountDocModel DirichletPriorDocModel JelinekMercerDocModel List of all members.

Public Methods

 SimpleKLDocModel (int docID,UnigramLM &collectLM)
 ~SimpleKLDocModel ()
virtual double termWeight (int termID,DocInfo *info)
 term weighting function, weight(w) = p_seen(w)/p_unseen(w).

virtual double scoreConstant ()
 doc-specific constant term in the scoring formula.

virtual double unseenCoeff ()=0
 a(d).

virtual double seenProb (double termFreq,int termID)=0
 p(w|d), w seen.


Protected Attributes

UnigramLMrefLM

Detailed Description

Doc representation for simple KL divergence retrieval model.

abstract interface of doc representation for smoothed document unigram model

adapt a smoothed document language model interface to a DocumentRep interface

 p(w|d) = q(w|d) if w seen
        = a(d) * Pc(w)  if w unseen
   where,  a(d) controls the probability mass allocated to all unseen words and     Pc(w) is the collection language model


Constructor & Destructor Documentation

SimpleKLDocModel::SimpleKLDocModel ( int docID,
UnigramLM & collectLM ) [inline]
 

SimpleKLDocModel::~SimpleKLDocModel ( ) [inline]
 


Member Function Documentation

double SimpleKLDocModel::scoreConstant ( ) [inline, virtual]
 

doc-specific constant term in the scoring formula.

Reimplemented from DocumentRep.

double SimpleKLDocModel::seenProb ( double termFreq,
int termID ) [pure virtual]
 

p(w|d), w seen.

Reimplemented in JelinekMercerDocModel, DirichletPriorDocModel, and AbsoluteDiscountDocModel.

double SimpleKLDocModel::termWeight ( int termID,
DocInfo * info ) [inline, virtual]
 

term weighting function, weight(w) = p_seen(w)/p_unseen(w).

Reimplemented from DocumentRep.

double SimpleKLDocModel::unseenCoeff ( ) [pure virtual]
 

a(d).

Reimplemented in JelinekMercerDocModel, DirichletPriorDocModel, and AbsoluteDiscountDocModel.


Member Data Documentation

UnigramLM & SimpleKLDocModel::refLM [protected]
 


The documentation for this class was generated from the following file:
Generated at Fri Jul 26 18:22:57 2002 for LEMUR by doxygen1.2.4 written by Dimitri van Heesch, © 1997-2000