lemur::retrieval::CosSimRetMethod Class Reference

Cosine similarity retrieval method. More...

#include <CosSimRetMethod.hpp>

Inheritance diagram for lemur::retrieval::CosSimRetMethod:

List of all members.


Public Member Functions
	CosSimRetMethod (const lemur::api::Index &dbIndex, lemur::api::ScoreAccumulator &accumulator)
	Precomputes the idf values for the collection.
	CosSimRetMethod (const lemur::api::Index &dbIndex, const string &L2file, lemur::api::ScoreAccumulator &accumulator)
virtual	~CosSimRetMethod ()
virtual lemur::api::TextQueryRep *	computeTextQueryRep (const lemur::api::TermQuery &qry)
virtual lemur::api::TextQueryRep *	computeTextQueryRep (lemur::api::DOCID_T docid)
	compute a query rep for an existing doc
virtual lemur::api::DocumentRep *	computeDocRep (lemur::api::DOCID_T docID)
	compute the doc representation (caller responsible for deleting the memory of the generated new instance)
virtual lemur::api::ScoreFunction *	scoreFunc ()
	return the scoring function pointer
virtual void	updateTextQuery (lemur::api::TextQueryRep &qryRep, const lemur::api::DocIDSet &relDocs)
	Use same as TFIDFRetMethod.
void	setFeedbackParam (CosSimParameter::FeedbackParam &feedbackParam)
Protected Member Functions
double	docNorm (lemur::api::DOCID_T docID)
	compute the L2 norm for a given docID.
void	loadDocNorms ()
	load the precomputed L2 norms support file.
Protected Attributes
double *	idfV
lemur::api::ScoreFunction *	scFunc
double *	docNorms
int	numDocs
int	numTerms
Parameters
CosSimParameter::FeedbackParam	fbParam
const string &	L2FileName
	Name of support file containing the precomputed L2 norms.

Detailed Description

Cosine similarity retrieval method.

Constructor & Destructor Documentation

lemur::retrieval::CosSimRetMethod::CosSimRetMethod ( const lemur::api::Index & dbIndex,

lemur::api::ScoreAccumulator & accumulator

)

Precomputes the idf values for the collection.

lemur::retrieval::CosSimRetMethod::CosSimRetMethod ( const lemur::api::Index & dbIndex,

const string & L2file,

lemur::api::ScoreAccumulator & accumulator

)

Precomputes the idf values for the collection. Loads the precomputed L2 document norms from L2File (if present). This support file is optional, if it is not found, L2 norms will be computed during scoring and cached across queries.

lemur::retrieval::CosSimRetMethod::~CosSimRetMethod ( ) [virtual]

Member Function Documentation

virtual lemur::api::DocumentRep* lemur::retrieval::CosSimRetMethod::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::CosSimRetMethod::computeTextQueryRep ( lemur::api::DOCID_T docid ) [inline, virtual]

compute a query rep for an existing doc

Reimplemented from lemur::api::TextQueryRetMethod.

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

double lemur::retrieval::CosSimRetMethod::docNorm ( lemur::api::DOCID_T docID ) [protected]

compute the L2 norm for a given docID.

void lemur::retrieval::CosSimRetMethod::loadDocNorms ( ) [protected]

load the precomputed L2 norms support file.

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

return the scoring function pointer

Implements lemur::api::TextQueryRetMethod.

void lemur::retrieval::CosSimRetMethod::setFeedbackParam ( CosSimParameter::FeedbackParam & feedbackParam ) [inline]

void lemur::retrieval::CosSimRetMethod::updateTextQuery ( lemur::api::TextQueryRep & qryRep,

const lemur::api::DocIDSet & relDocs

) [virtual]

Use same as TFIDFRetMethod.