Implements Sequential_Forward_Selection and Sequential_Backward_Selection. More...

#include <search_seq_sfs.hpp>

Inheritance diagram for FST::Search_SFS< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >:

Classes
struct	OneSubset
	Structure to hold [subset,criterion value] temporary solutions in the course of search. More...

Public Types
typedef Search_Sequential< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >	parent
	base class alias
typedef parent::parent	grandparent
	the shared Search base (output detail, result tracker)
typedef std::shared_ptr< EVALUATOR >	PEvaluator
	shared pointer to the sequential-step evaluator
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
Public Types inherited from FST::Search_Sequential< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >
typedef Search< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >	parent
	base class alias
typedef std::shared_ptr< EVALUATOR >	PEvaluator
	shared pointer to the sequential-step evaluator that implements Step()'s candidate generation and selection
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
Public Types inherited from FST::Search< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >
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 std::shared_ptr< Result_Tracker< RETURNTYPE, SUBSET > >	PResultTracker
	shared pointer to the result tracker enabled via enable_result_tracking()
typedef Search_Observer< RETURNTYPE, SUBSET >	OBSERVER
	the observer interface type this search reports through (see Search_Observer)
typedef std::shared_ptr< OBSERVER >	PObserver
	shared pointer to an OBSERVER, as set via set_observer()

Public Member Functions
	Search_SFS (const PEvaluator evaluator)
	`evaluator` must be non-null; direction defaults to FORWARD (SFS); call set_search_direction(BACKWARD) for SBS
virtual bool	search (const DIMTYPE target_d, RETURNTYPE &result, const PSubset sub, const PCriterion crit, std::ostream &os=std::cout) override
	Runs SFS (or SBS) and returns the resulting subset + its criterion value.
void	set_search_direction (const SearchDirection direction)
	FORWARD implies SFS, BACKWARD implies SBS (do not change concurrently to running search()).
SearchDirection	get_search_direction () const
	the currently configured direction (see set_search_direction())
bool	get_result (const DIMTYPE d, RETURNTYPE &result, PSubset &sub)
	retrieves the subset of cardinality `d` (1-based: d ranges over 1..n) recorded during the last search(), together with its criterion value; false if that search recorded nothing at this cardinality - which is the case for every size it did not visit, and for all sizes if it returned false. The contents are copied into `sub`, which must be non-null and dimensioned for the full feature set
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_Sequential< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >
	Search_Sequential (const PEvaluator evaluator)
	`evaluator` must be non-null
bool	Step (const bool forward, RETURNTYPE &result, const PSubset sub, const PCriterion crit, std::ostream &os=std::cout)
	Performs one sequential step: adds (`forward`) or removes (!`forward`) the best g-tuple of features, g being the generalization level.
void	set_generalization_level (const DIMTYPE g)
	optional parameter to enlarge the number of considered candidates (g is the number of features added/removed in one Step)
DIMTYPE	get_generalization_level () const
	the currently configured generalization level (see set_generalization_level())
void	enable_initial_subset ()
	makes search() start from the caller-supplied contents of its `sub` argument instead of the concrete method's default (empty set for FORWARD, full set for BACKWARD)
void	disable_initial_subset ()
	reverts to the default: incoming `sub` contents are ignored by search()
bool	initial_subset_enabled () const
	true if enable_initial_subset() was called (and not since disabled by disable_initial_subset())
Public Member Functions inherited from FST::Search< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >
void	enable_result_tracking (PResultTracker tracker)
	assigns a result tracker to the search process, i.e., enables logging of all evaluated subsets for future reuse (re-evaluation, etc.)
void	disable_result_tracking ()
	detaches any result tracker (result_tracker_active() then returns false)
bool	result_tracker_active () const
	true if a result tracker was assigned via enable_result_tracking() and not since disabled
void	set_output_detail (OutputDetail detail)
	sets the amount of information that is logged to output stream throughout the course of search
OutputDetail	get_output_detail () const
	the currently configured output detail level
bool	output_normal () const
	true unless output detail is SILENT
bool	output_detailed () const
	true only at the DETAILED output level
void	set_observer (PObserver observer)
	redirects search progress reporting away from the default syncout text output to `observer`

Protected Attributes
SearchDirection	_direction
std::unique_ptr< OneSubset[]>	bsubs
	per-cardinality result found in the course of the last search() (index d-1); read by get_result()
DIMTYPE	_n
	bsubs array size
Protected Attributes inherited from FST::Search_Sequential< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >
PEvaluator	_evaluator
	the sequential-step evaluator injected at construction; drives Step()'s candidate generation and best/worst choice
DIMTYPE	_generalization_level
	number of features added/removed together in one Step() call (see set_generalization_level())
bool	_initial_subset_enabled
	by default all concrete search methods ignore the contents of supplied 'PSubset set' and initialize sub according to their definition; if enabled, then (if possible) the search() starts from supplied 'PSubset sub' contents
Protected Attributes inherited from FST::Search< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >
PResultTracker	_tracker
	the assigned result tracker, or null (see enable_result_tracking()/result_tracker_active())
OutputDetail	_detail
	the output detail level set via set_output_detail(); read by output_normal()/output_detailed()
PObserver	_observer
	the attached progress observer, or null (see set_observer(), report(), report_solution())

Additional Inherited Members
Protected Member Functions inherited from FST::Search< RETURNTYPE, DIMTYPE, SUBSET, CRITERION >
void	report (std::ostream &os, const msgbuf &m) const
	delivers one pre-formatted progress message: to the observer if attached, otherwise as syncout text to os
void	report_solution (std::ostream &os, const RETURNTYPE value, const SUBSET &sub, const msgbuf &m) const
	like report(), for sites announcing a new (sub-)solution; fires on_solution instead

Detailed Description

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

Implements Sequential_Forward_Selection and Sequential_Backward_Selection.

Note: By default any initial subset contents are ignored; SFS starts from empty set and SBS starts from full set. Call enable_initial_subset() to let the search start from the initial sub contents.

Examples: demo10.cpp.

Member Function Documentation

◆ print()

template<class RETURNTYPE, typename DIMTYPE, class SUBSET, class CRITERION, class EVALUATOR>

std::ostream & FST::Search_SFS< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >::print ( std::ostream & os ) const

overridevirtual

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

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

◆ search()

template<class RETURNTYPE, typename DIMTYPE, class SUBSET, class CRITERION, class EVALUATOR>

bool FST::Search_SFS< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >::search	(	const DIMTYPE	target_d,
		RETURNTYPE &	result,
		const PSubset	sub,
		const PCriterion	crit,
		std::ostream &	os = std::cout )

overridevirtual

Runs SFS (or SBS) and returns the resulting subset + its criterion value.

Starts from the empty set (FORWARD) or the full set (BACKWARD), unless enable_initial_subset() was called, in which case the incoming contents of sub are the starting point. Each step adds (removes) the best g-tuple of features, g being the generalization level, until target_d features are selected; with target_d==0 the search runs to the end of its range and returns the best-valued subset among all sizes visited.

Returns: false if the criterion failed on some subset, or if the requested combination of starting size, target_d and generalization level makes a solution unreachable (see the reachability test at the start of the body): for instance a forward search asked for fewer features than it starts with, or a target_d not reachable by whole g-sized steps.

Implements FST::Search_Sequential< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >.

Examples: demo10.cpp.

Member Data Documentation

◆ _direction

template<class RETURNTYPE, typename DIMTYPE, class SUBSET, class CRITERION, class EVALUATOR>

SearchDirection FST::Search_SFS< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >::_direction

protected

accepted values FORWARD for SFS or BACKWARD for SBS

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

/Users/psms/dev/devtest1/_src_search/search_seq_sfs.hpp

Classes

Public Types

Public Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ print()

◆ search()

Member Data Documentation

◆ _direction