quickrank::metric::ir::Dcg Class Reference

This class implements the Discounted cumulative Gain DCG@K measure. More...

#include <dcg.h>

Inheritance diagram for quickrank::metric::ir::Dcg:

Public Member Functions
	Dcg (size_t k=NO_CUTOFF)
virtual	~Dcg ()
virtual std::string	name () const
	Returns the name of the metric. More...
virtual MetricScore	evaluate_result_list (const quickrank::data::QueryResults *rl, const Score *scores) const
	Measures the quality of the given results list according to the Metric. More...
virtual std::unique_ptr< Jacobian >	jacobian (std::shared_ptr< data::RankedResults > ranked) const
	Computes the Jacobian matrix. More...
Public Member Functions inherited from quickrank::metric::ir::Metric
	Metric (size_t k=NO_CUTOFF)
	Creates a new metric with the specified cut-off threshold. More...
virtual	~Metric ()
size_t	cutoff () const
	Returns the current cut-off of the Metric. More...
void	set_cutoff (size_t k)
	Updates the cut-off of the Metric. More...
virtual MetricScore	evaluate_dataset (const std::shared_ptr< data::Dataset > dataset, const Score *scores) const
virtual MetricScore	evaluate_dataset (const std::shared_ptr< data::VerticalDataset > dataset, const Score *scores) const

Static Public Attributes
static const std::string	NAME_ = "DCG"
Static Public Attributes inherited from quickrank::metric::ir::Metric
static const size_t	NO_CUTOFF = SIZE_MAX
	This should be used when no cut-off on the results list is required. More...

Protected Member Functions
MetricScore	compute_dcg (const Label *labels, size_t len) const
	Computes the DCG@K of a given array of labels. More...

Private Member Functions
virtual std::ostream &	put (std::ostream &os) const
	Prints the short name of the Metric, e.g., "NDCG@K". More...

Friends
std::ostream &	operator<< (std::ostream &os, const Dcg &ndcg)

Detailed Description

This class implements the Discounted cumulative Gain DCG@K measure.

DCG is measured as: \( DCG_k = \sum_{i=1}^k \frac{2^{l_i}-1}{\log_2 (i+1)}\), where \(l_i\) is the relevance label of the i-th document.

Constructor & Destructor Documentation

quickrank::metric::ir::Dcg::Dcg ( size_t  k = NO_CUTOFF )

inlineexplicit

virtual quickrank::metric::ir::Dcg::~Dcg ( )

inlinevirtual

Member Function Documentation

MetricScore quickrank::metric::ir::Dcg::compute_dcg ( const Label *  labels, size_t  len  ) const

protected

Computes the DCG@K of a given array of labels.

Parameters

rl	The given array of labels.

Returns

DCG@K for computed on the given labels.

MetricScore quickrank::metric::ir::Dcg::evaluate_result_list ( const quickrank::data::QueryResults *  rl, const Score *  scores  ) const

virtual

Measures the quality of the given results list according to the Metric.

Parameters

rl	A results list.
scores	a list of scores

Returns

The quality score of the result list.

Implements quickrank::metric::ir::Metric.

Reimplemented in quickrank::metric::ir::Ndcg, and quickrank::metric::ir::Tndcg.

std::unique_ptr< Jacobian > quickrank::metric::ir::Dcg::jacobian ( std::shared_ptr< data::RankedResults >  ranked ) const

virtual

Computes the Jacobian matrix.

This is a symmetric matrix storing the metric "decrease" when two documents scores are swapped.

Parameters

rl	A results list.

Returns

A smart-pointer to the Jacobian Matrix.

Todo:

TODO: provide def implementation

Reimplemented from quickrank::metric::ir::Metric.

Reimplemented in quickrank::metric::ir::Ndcg, and quickrank::metric::ir::Tndcg.

virtual std::string quickrank::metric::ir::Dcg::name ( ) const

inlinevirtual

Returns the name of the metric.

Implements quickrank::metric::ir::Metric.

Reimplemented in quickrank::metric::ir::Ndcg, and quickrank::metric::ir::Tndcg.

std::ostream & quickrank::metric::ir::Dcg::put ( std::ostream &  os ) const

privatevirtual

Prints the short name of the Metric, e.g., "NDCG@K".

Implements quickrank::metric::ir::Metric.

Reimplemented in quickrank::metric::ir::Tndcg, and quickrank::metric::ir::Ndcg.

Friends And Related Function Documentation

std::ostream& operator<< ( std::ostream &  os, const Dcg &  ndcg  )

friend

Member Data Documentation

const std::string quickrank::metric::ir::Dcg::NAME_ = "DCG"

static

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The documentation for this class was generated from the following files:

• include/metric/ir/dcg.h
• src/metric/ir/dcg.cc