Implements Bhattacharyya distance based on multinomial model to serve as feature selection criterion. More...

#include <criterion_multinom_bhattacharyya.hpp>

Inheritance diagram for FST::Criterion_Multinomial_Bhattacharyya< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >:

Public Types
typedef Criterion_Multinomial< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >	parent
	base class: the multinomial-model learning/interface skeleton
typedef Clonable_Impl< Criterion_Multinomial_Bhattacharyya, parent >	parent_impl
	implements clone(); sharing/stateless_clone throw in Criterion
typedef std::shared_ptr< DATAACCESSOR >	PDataAccessor
	shared pointer to the data accessor the model is learned from
typedef std::shared_ptr< SUBSET >	PSubset
	shared pointer to the feature subset being evaluated
Public Types inherited from FST::Criterion_Multinomial< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >
typedef std::shared_ptr< DATAACCESSOR >	PDataAccessor
	shared pointer to the data accessor the model is learned from
typedef std::shared_ptr< SUBSET >	PSubset
	shared pointer to the feature subset being evaluated
Public Types inherited from FST::Criterion_Filter< RETURNTYPE, SUBSET >
typedef std::shared_ptr< SUBSET >	PSubset
	shared pointer to the feature subset being evaluated
Public Types inherited from FST::Criterion< RETURNTYPE, SUBSET >
typedef std::shared_ptr< SUBSET >	PSubset
	shared pointer to the feature subset being evaluated

Public Member Functions
virtual bool	evaluate (RETURNTYPE &result, const PSubset sub) override
	Scores `sub:` the general multinomial Bhattacharyya distance over class pairs, or (on a singleton) the individual Bhattacharyya term.
virtual bool	initialize (PDataAccessor da) override
	learns the model (parent::initialize()) and resets the lazily-computed individual-Bhattacharyya cache
virtual std::ostream &	print (std::ostream &os) const override
	writes a human-readable identification of the object; base default writes nothing
Public Member Functions inherited from FST::Clonable_Impl< Criterion_Multinomial_Bhattacharyya< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >, Criterion_Multinomial< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR > >
Criterion_Multinomial< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR > *	clone () const override
	dispatches to the DEEP_KIND mechanism (default CLONE_DEEP: Derived's copy-constructor)
Criterion_Multinomial< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR > *	sharing_clone () const override
	dispatches to the SHARING_KIND mechanism (default CLONE_INHERIT: defers to Base, which throws by family convention)
Criterion_Multinomial< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR > *	stateless_clone () const override
	dispatches to the STATELESS_KIND mechanism (default CLONE_INHERIT: defers to Base, which throws by family convention)
Public Member Functions inherited from FST::Criterion_Multinomial< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >
virtual bool	is_monotonic () const override
DIMTYPE	get_n () const
	the full (raw, unnarrowed) feature count the model was learned for
DIMTYPE	get_d () const
	the currently active (narrowed) feature count
Public Member Functions inherited from FST::Criterion< RETURNTYPE, SUBSET >
Criterion *	sharing_clone () const override
Criterion *	stateless_clone () const override
Public Member Functions inherited from FST::Clonable
bool	is_clone () const
bool	is_sharing () const
	true if this instance is a sharing_clone() result (referencing, not owning, the source's structures)
bool	is_sharing_clone () const
	true if this instance is BOTH a clone and sharing – i.e. specifically a sharing_clone() result, not a clone()/stateless_clone() one

Private Member Functions
	Criterion_Multinomial_Bhattacharyya (const Criterion_Multinomial_Bhattacharyya &cmb)
	Copy-constructor; copies _IB_computed (base _model copied by parent_impl).

Private Attributes
friend	parent_impl
bool	_IB_computed
	true once the per-feature individual-Bhattacharyya cache (Model_Multinomial::get_IB()) has been computed for the current model

Additional Inherited Members
Protected Member Functions inherited from FST::Criterion_Multinomial< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >
	Criterion_Multinomial (const Criterion_Multinomial &cm)
	Copy-constructor; deep-copies _model.
Protected Member Functions inherited from FST::Clonable
void	set_cloned (const bool cloned=true)
	marks/unmarks this instance as a clone; call from clone()/stateless_clone() overrides (Clonable_Impl does this automatically)
void	set_sharing (const bool sharing=true)
	marks/unmarks this instance as sharing (see is_sharing())
void	set_sharing_cloned (const bool cloned=true, const bool sharing=true)
	sets both flags at once; call from sharing_clone() overrides (Clonable_Impl does this automatically)
Protected Attributes inherited from FST::Criterion_Multinomial< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >
std::unique_ptr< Model_Multinomial< DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR > >	_model
	the learned per-class multinomial (term-probability) model

Detailed Description

template<class RETURNTYPE, typename DATATYPE, typename REALTYPE, typename IDXTYPE, typename DIMTYPE, class SUBSET, class DATAACCESSOR>
class FST::Criterion_Multinomial_Bhattacharyya< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >

Implements Bhattacharyya distance based on multinomial model to serve as feature selection criterion.

Warning: The value returned depends on the subset SIZE in kind, not only in magnitude: for d > 1 it is the general multinomial Bhattacharyya distance (a prior-weighted sum over class pairs of -log of the Bhattacharyya coefficient of the two term distributions, scaled by the average document length), while for d == 1 the general form degenerates and the criterion returns the cached INDIVIDUAL Bhattacharyya value of that one feature instead. The two are on different scales, so values obtained for singletons must not be compared with values obtained for larger subsets. In practice this matters when a search visits subsets of size 1 (e.g. the first step of a forward sequential search or a ranking search) - the ordering WITHIN each size is meaningful regardless.

Member Function Documentation

◆ evaluate()

template<class RETURNTYPE, typename DATATYPE, typename REALTYPE, typename IDXTYPE, typename DIMTYPE, class SUBSET, class DATAACCESSOR>

bool FST::Criterion_Multinomial_Bhattacharyya< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >::evaluate	(	RETURNTYPE &	result,
		const PSubset	sub )

overridevirtual

Scores sub: the general multinomial Bhattacharyya distance over class pairs, or (on a singleton) the individual Bhattacharyya term.

Implements FST::Criterion_Multinomial< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >.

◆ initialize()

template<class RETURNTYPE, typename DATATYPE, typename REALTYPE, typename IDXTYPE, typename DIMTYPE, class SUBSET, class DATAACCESSOR>

bool FST::Criterion_Multinomial_Bhattacharyya< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >::initialize ( PDataAccessor da )

overridevirtual

learns the model (parent::initialize()) and resets the lazily-computed individual-Bhattacharyya cache

Reimplemented from FST::Criterion_Multinomial< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >.

◆ print()

template<class RETURNTYPE, typename DATATYPE, typename REALTYPE, typename IDXTYPE, typename DIMTYPE, class SUBSET, class DATAACCESSOR>

virtual std::ostream & FST::Criterion_Multinomial_Bhattacharyya< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >::print ( std::ostream & os ) const

inlineoverridevirtual

writes a human-readable identification of the object; base default writes nothing

Reimplemented from FST::Clonable.

Member Data Documentation

◆ parent_impl

template<class RETURNTYPE, typename DATATYPE, typename REALTYPE, typename IDXTYPE, typename DIMTYPE, class SUBSET, class DATAACCESSOR>

friend FST::Criterion_Multinomial_Bhattacharyya< RETURNTYPE, DATATYPE, REALTYPE, IDXTYPE, DIMTYPE, SUBSET, DATAACCESSOR >::parent_impl

private

grants Clonable_Impl access to the copy-constructor

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

/Users/psms/dev/devtest1/_src_criteria/criterion_multinom_bhattacharyya.hpp

Public Types

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ evaluate()

◆ initialize()

◆ print()

Member Data Documentation

◆ parent_impl