Abstract class, defines interface for sequential search method implementations, provides common implementation of the "sequential step" operation. More...

#include <search_seq.hpp>

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

Public Types
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_Sequential (const PEvaluator evaluator)
	`evaluator` must be non-null
virtual bool	search (const DIMTYPE target_d, RETURNTYPE &result, const PSubset sub, const PCriterion crit, std::ostream &os) override=0
	returns the found subset of target_d features + its criterion value; target_d==0 asks the method to pick the best subset size itself (it then keeps the best-valued subset over all sizes it visits)
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`
virtual std::ostream &	print (std::ostream &os) const
	writes a human-readable identification of the search and its configuration; base default writes nothing

Protected Attributes
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_Sequential< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >

Abstract class, defines interface for sequential search method implementations, provides common implementation of the "sequential step" operation.

Note: To prevent misunderstanding: _generalization_level here does not relate to classification performance on unknown data, but to "generalization" of the course of search, i.e., the number of features added/removed while generating candidate subsets in one sequential step (higher generalization=more candidates). See book Devijver, Kittler, 1982 for discussion.

Member Function Documentation

◆ search()

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

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

overridepure virtual

returns the found subset of target_d features + its criterion value; target_d==0 asks the method to pick the best subset size itself (it then keeps the best-valued subset over all sizes it visits)

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

Implemented in FST::Search_DOS< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >, FST::Search_OS< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >, FST::Search_SFFS< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >, FST::Search_SFRS< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >, and FST::Search_SFS< RETURNTYPE, DIMTYPE, SUBSET, CRITERION, EVALUATOR >.

◆ Step()

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

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

inline

Performs one sequential step: adds (forward) or removes (!forward) the best g-tuple of features, g being the generalization level.

The work is done by the injected evaluator, which replaces sub's contents by the candidate it chose and stores its criterion value in result. The subset's forward/backward mode is switched for the duration of the call and restored afterwards, so a backward step inside a forward search costs nothing but the step itself.

Returns: the evaluator's success flag: false if it could not generate a candidate (nothing left to add or remove) or a criterion evaluation failed. sub is the traversal state of the candidate enumeration and may have been modified even then - it is the caller's business to abandon the search.

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

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

Public Types

Public Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ search()

◆ Step()