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lemur::retrieval::SimpleKLScoreFunc Class Reference

Simple KL-divergence scoring function. More...

#include <SimpleKLRetMethod.hpp>

Inheritance diagram for lemur::retrieval::SimpleKLScoreFunc:

lemur::api::ScoreFunction List of all members.

Public Member Functions

void setScoreMethod (enum SimpleKLParameter::adjustedScoreMethods adj)
virtual double matchedTermWeight (const lemur::api::QueryTerm *qTerm, const lemur::api::TextQueryRep *qRep, const lemur::api::DocInfo *info, const lemur::api::DocumentRep *dRep) const
virtual double adjustedScore (double origScore, const lemur::api::TextQueryRep *qRep, const lemur::api::DocumentRep *dRep) const
 score adjustment (e.g., appropriate length normalization)

Public Attributes

enum SimpleKLParameter::adjustedScoreMethods adjScoreMethod

Detailed Description

Simple KL-divergence scoring function.

The KL-divergence formula D(model_q || model_d), when used for ranking documents, can be computed efficiently by re-writing the formula as a sum over all matched terms in a query and a document. The details of such rewriting are described in the following two papers:

Member Function Documentation

virtual double lemur::retrieval::SimpleKLScoreFunc::adjustedScore double  origScore,
const lemur::api::TextQueryRep qRep,
const lemur::api::DocumentRep dRep
const [inline, virtual]

score adjustment (e.g., appropriate length normalization)

The following are three different options for scoring

==== Option 1: query likelihood ==============

==== Option 2: cross-entropy (normalized query likelihood) ====

==== Option 3: negative KL-divergence ====

virtual double lemur::retrieval::SimpleKLScoreFunc::matchedTermWeight const lemur::api::QueryTerm qTerm,
const lemur::api::TextQueryRep qRep,
const lemur::api::DocInfo info,
const lemur::api::DocumentRep dRep
const [inline, virtual]

void lemur::retrieval::SimpleKLScoreFunc::setScoreMethod enum SimpleKLParameter::adjustedScoreMethods  adj  )  [inline]

Member Data Documentation

enum SimpleKLParameter::adjustedScoreMethods lemur::retrieval::SimpleKLScoreFunc::adjScoreMethod

The documentation for this class was generated from the following file:
Generated on Tue Jun 15 11:03:06 2010 for Lemur by doxygen 1.3.4