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OkapiRetMethod Class Reference

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

#include <OkapiRetMethod.hpp>

Inheritance diagram for OkapiRetMethod:

TextQueryRetMethod RetrievalMethod List of all members.

Public Methods

 OkapiRetMethod (const Index &dbIndex, ScoreAccumulator &accumulator)
virtual ~OkapiRetMethod ()
virtual TextQueryRep * computeTextQueryRep (const TermQuery &qry)
 compute the query representation for a text query (caller responsible for deleting the memory of the generated new instance)

virtual DocumentRep * computeDocRep (DOCID_T docID)
 compute the doc representation (caller responsible for deleting the memory of the generated new instance)

virtual ScoreFunction * scoreFunc ()
 return the scoring function pointer

virtual void updateTextQuery (TextQueryRep &origRep, const 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 Methods

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


Protected Attributes

OkapiScoreFunc * scFunc
OkapiParameter::TFParam tfParam
OkapiParameter::FeedbackParam fbParam

Detailed Description

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

Constructor & Destructor Documentation

OkapiRetMethod::OkapiRetMethod (  const Index &    dbIndex,
ScoreAccumulator &    accumulator
) 
 

virtual OkapiRetMethod::~OkapiRetMethod (    )  [inline, virtual]
 

Member Function Documentation

virtual DocumentRep* OkapiRetMethod::computeDocRep (  DOCID_T    docID )  [inline, virtual]
 

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

Implements TextQueryRetMethod.

virtual TextQueryRep* OkapiRetMethod::computeTextQueryRep (  const TermQuery &    qry )  [inline, virtual]
 

compute the query representation for a text query (caller responsible for deleting the memory of the generated new instance)

Implements TextQueryRetMethod.

double OkapiRetMethod::RSJWeight (  double    r,
double    R,
double    n,
double    N
)  [inline, static]
 

Compute the Robertson Spark Jones Weight.

ScoreFunction * OkapiRetMethod::scoreFunc (    )  [inline, virtual]
 

return the scoring function pointer

Implements TextQueryRetMethod.

void OkapiRetMethod::setFeedbackParam (  OkapiParameter::FeedbackParam &    feedbackParam )  [inline]
 

void OkapiRetMethod::setTFParam (  OkapiParameter::TFParam &    tfWeightParam )  [inline]
 

void OkapiRetMethod::updateTextQuery (  TextQueryRep &    origRep,
const DocIDSet &    relDocs
)  [virtual]
 

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

Implements TextQueryRetMethod.

Member Data Documentation

OkapiParameter::FeedbackParam OkapiRetMethod::fbParam [protected]
 

OkapiScoreFunc* OkapiRetMethod::scFunc [protected]
 

OkapiParameter::TFParam OkapiRetMethod::tfParam [protected]
 

The documentation for this class was generated from the following files:
Generated on Wed Nov 3 12:59:49 2004 for Lemur Toolkit by doxygen1.2.18