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lemur::retrieval::OkapiRetMethod Class Reference

The Okapi BM25 retrieval function, as described in their TREC-3 paper. More...

#include <OkapiRetMethod.hpp>

Inheritance diagram for lemur::retrieval::OkapiRetMethod:

lemur::api::TextQueryRetMethod lemur::api::RetrievalMethod List of all members.

Public Member Functions

 OkapiRetMethod (const lemur::api::Index &dbIndex, lemur::api::ScoreAccumulator &accumulator)
virtual ~OkapiRetMethod ()
virtual lemur::api::TextQueryRepcomputeTextQueryRep (const lemur::api::TermQuery &qry)
virtual lemur::api::DocumentRepcomputeDocRep (lemur::api::DOCID_T docID)
 compute the doc representation (caller responsible for deleting the memory of the generated new instance)

virtual lemur::api::ScoreFunctionscoreFunc ()
 return the scoring function pointer

virtual void updateTextQuery (lemur::api::TextQueryRep &origRep, const lemur::api::DocIDSet &relDocs)
 It's suspected that there is a bug in the implementation of feedback; the performance is not as expected.

void setTFParam (OkapiParameter::TFParam &tfWeightParam)
void setFeedbackParam (OkapiParameter::FeedbackParam &feedbackParam)

Static Public Member Functions

double RSJWeight (double r, double R, double n, double N)
 Compute the Robertson Spark Jones Weight.


Protected Attributes

OkapiScoreFuncscFunc
OkapiParameter::TFParam tfParam
OkapiParameter::FeedbackParam fbParam

Detailed Description

The Okapi BM25 retrieval function, as described in their TREC-3 paper.


Constructor & Destructor Documentation

lemur::retrieval::OkapiRetMethod::OkapiRetMethod const lemur::api::Index dbIndex,
lemur::api::ScoreAccumulator accumulator
 

virtual lemur::retrieval::OkapiRetMethod::~OkapiRetMethod  )  [inline, virtual]
 


Member Function Documentation

virtual lemur::api::DocumentRep* lemur::retrieval::OkapiRetMethod::computeDocRep lemur::api::DOCID_T  docID  )  [inline, virtual]
 

compute the doc representation (caller responsible for deleting the memory of the generated new instance)

Implements lemur::api::TextQueryRetMethod.

virtual lemur::api::TextQueryRep* lemur::retrieval::OkapiRetMethod::computeTextQueryRep const lemur::api::TermQuery qry  )  [inline, virtual]
 

double lemur::retrieval::OkapiRetMethod::RSJWeight double  r,
double  R,
double  n,
double  N
[inline, static]
 

Compute the Robertson Spark Jones Weight.

lemur::api::ScoreFunction * lemur::retrieval::OkapiRetMethod::scoreFunc  )  [inline, virtual]
 

return the scoring function pointer

Implements lemur::api::TextQueryRetMethod.

void lemur::retrieval::OkapiRetMethod::setFeedbackParam OkapiParameter::FeedbackParam feedbackParam  )  [inline]
 

void lemur::retrieval::OkapiRetMethod::setTFParam OkapiParameter::TFParam tfWeightParam  )  [inline]
 

void lemur::retrieval::OkapiRetMethod::updateTextQuery lemur::api::TextQueryRep origRep,
const lemur::api::DocIDSet relDocs
[virtual]
 

It's suspected that there is a bug in the implementation of feedback; the performance is not as expected.


Member Data Documentation

OkapiParameter::FeedbackParam lemur::retrieval::OkapiRetMethod::fbParam [protected]
 

OkapiScoreFunc* lemur::retrieval::OkapiRetMethod::scFunc [protected]
 

OkapiParameter::TFParam lemur::retrieval::OkapiRetMethod::tfParam [protected]
 


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