Feature Selection Toolbox FST4
UTIA · Czech Academy of Sciences
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FST::Search_Ranking_BIF< RETURNTYPE, DIMTYPE, SUBSET, CRITERION > Class Template Reference

Implements Best Individual Features, i.e., individual feature ranking. More...

#include <search_ranking_bif.hpp>

Inheritance diagram for FST::Search_Ranking_BIF< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >:
FST::Search_Ranking< RETURNTYPE, DIMTYPE, SUBSET, CRITERION > FST::Search< RETURNTYPE, DIMTYPE, SUBSET, CRITERION > FST::Search_Ranking_BIF_Threaded< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >

Public Types

typedef Search_Ranking< RETURNTYPE, DIMTYPE, SUBSET, CRITERION > parent
 base class: the individual-ranking search skeleton (final best-dimensionality scan, feature-list bookkeeping)
typedef std::shared_ptr< CRITERION > PCriterion
 shared pointer to the criterion being optimized
typedef std::shared_ptr< SUBSET > PSubset
 shared pointer to a feature subset
typedef parent::PEvaluatorEngine PEvaluatorEngine
 the candidate-evaluation engine type, inherited from parent
Public Types inherited from FST::Search_Ranking< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >
typedef Search< RETURNTYPE, DIMTYPE, SUBSET, CRITERION > parent
 the abstract Search interface this class implements
typedef std::shared_ptr< CRITERION > PCriterion
 shared pointer to the criterion the search optimizes
typedef std::shared_ptr< SUBSET > PSubset
 shared pointer to a feature subset
typedef Candidate_Evaluator< RETURNTYPE, DIMTYPE, SUBSET, CRITERION > EVALUATORENGINE
 the injected candidate-evaluation engine interface driving individual-feature evaluation
typedef std::shared_ptr< EVALUATORENGINE > PEvaluatorEngine
Public Types inherited from FST::Search< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >
 shared pointer to the criterion the search optimizes
 shared pointer to a feature subset
 shared pointer to the result tracker enabled via enable_result_tracking()
 the observer interface type this search reports through (see Search_Observer)
 shared pointer to an OBSERVER, as set via set_observer()

Public Member Functions

 Search_Ranking_BIF (PEvaluatorEngine engine=PEvaluatorEngine())
 Constructs the search with the given candidate-evaluation engine; a default-constructed engine falls back to sequential in-line evaluation.
virtual bool evaluate_individuals (const DIMTYPE n, const PCriterion crit, std::ostream &os=std::cout) override
 Scores every single feature individually under crit and ranks them into parent::bifs (descending), the BIF core step consumed by Search_Ranking::search().
virtual std::ostream & print (std::ostream &os) const override
 writes a human-readable identification of the search and its configuration; base default writes nothing
Public Member Functions inherited from FST::Search_Ranking< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >
 Search_Ranking (PEvaluatorEngine engine=PEvaluatorEngine())
virtual bool search (const DIMTYPE target_d, RETURNTYPE &result, const PSubset sub, const PCriterion crit, std::ostream &os=std::cout) override
 ranks the features (evaluate_individuals()) and returns the target_d best-ranked ones, or - for target_d==0 - the best-valued prefix of the ranking; false if the ranking or one of the criterion evaluations failed. target_d must be smaller than the full feature count
bool getFirstFeature (RETURNTYPE &value, DIMTYPE &feature) const
 iterator over bifs (the ranking built by evaluate_individuals()), highest-ranked feature first; returns false if bifs is empty
bool getNextFeature (RETURNTYPE &value, DIMTYPE &feature) const
 continues the getFirstFeature() iteration; returns false once the ranking is exhausted. There is one cursor per object: it is protected against concurrent access in threaded builds, but two interleaved iterations of the same object still consume one another's positions
Public Member Functions inherited from FST::Search< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >
 assigns a result tracker to the search process, i.e., enables logging of all evaluated subsets for future reuse (re-evaluation, etc.)
 detaches any result tracker (result_tracker_active() then returns false)
 true if a result tracker was assigned via enable_result_tracking() and not since disabled
 sets the amount of information that is logged to output stream throughout the course of search
 the currently configured output detail level
 true unless output detail is SILENT
 true only at the DETAILED output level
 redirects search progress reporting away from the default syncout text output to observer

Additional Inherited Members

Protected Types inherited from FST::Search_Ranking< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >
typedef std::list< OneFeature > FEATURELIST
 the individual-feature ranking built by evaluate_individuals(), sorted descending by critval
Protected Member Functions inherited from FST::Search< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >
 delivers one pre-formatted progress message: to the observer if attached, otherwise as syncout text to os
 like report(), for sites announcing a new (sub-)solution; fires on_solution instead
Protected Attributes inherited from FST::Search_Ranking< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >
PEvaluatorEngine _engine
FEATURELIST bifs
 the individual-feature ranking; empty until evaluate_individuals() is called
Protected Attributes inherited from FST::Search< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >
 the assigned result tracker, or null (see enable_result_tracking()/result_tracker_active())
 the output detail level set via set_output_detail(); read by output_normal()/output_detailed()
 the attached progress observer, or null (see set_observer(), report(), report_solution())

Detailed Description

template<class RETURNTYPE, typename DIMTYPE, class SUBSET, class CRITERION>
class FST::Search_Ranking_BIF< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >

Implements Best Individual Features, i.e., individual feature ranking.

Each feature is evaluated alone, as a subset of size one, and the features are ordered by descending criterion value; the inherited Search_Ranking::search() then turns that ranking into the resulting subset.

Note
This single class serves both the sequential and the threaded execution model: the evaluation strategy (a Candidate_Evaluator implementation) is injected through the constructor and defaults to sequential in-line evaluation. The best-dimensionality scan in the inherited Search_Ranking::search() runs through the same engine. The ranking does not depend on the engine - the same features are ranked in the same order at any thread count.

Constructor & Destructor Documentation

◆ Search_Ranking_BIF()

template<class RETURNTYPE, typename DIMTYPE, class SUBSET, class CRITERION>
FST::Search_Ranking_BIF< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >::Search_Ranking_BIF ( PEvaluatorEngine engine = PEvaluatorEngine())
inlineexplicit

Constructs the search with the given candidate-evaluation engine; a default-constructed engine falls back to sequential in-line evaluation.

Parameters
enginethe evaluation strategy to use; pass a Candidate_Evaluator_Threaded to evaluate the individual features in a thread pool

Member Function Documentation

◆ evaluate_individuals()

template<class RETURNTYPE, typename DIMTYPE, class SUBSET, class CRITERION>
bool FST::Search_Ranking_BIF< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >::evaluate_individuals ( const DIMTYPE n,
const PCriterion crit,
std::ostream & os = std::cout )
overridevirtual

Scores every single feature individually under crit and ranks them into parent::bifs (descending), the BIF core step consumed by Search_Ranking::search().

Parameters
nnumber of features to evaluate (features 0..n-1)
critthe criterion each singleton feature subset is scored with
osstream progress messages are reported to at NORMAL/DETAILED output detail
Returns
false if any individual evaluation fails (the candidate evaluator's add_candidate()/collect() returned false)
Note
Features of equal criterion value end up in descending feature-index order, because each newly ranked feature is inserted ahead of the equally valued ones already in the list. The order matters: it decides which of the tied features enter a subset of a given size.

Implements FST::Search_Ranking< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >.

◆ print()

template<class RETURNTYPE, typename DIMTYPE, class SUBSET, class CRITERION>
virtual std::ostream & FST::Search_Ranking_BIF< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >::print ( std::ostream & os) const
inlineoverridevirtual

writes a human-readable identification of the search and its configuration; base default writes nothing

Reimplemented from FST::Search_Ranking< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >.

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