SHOGUN  3.2.1
CFeatureSelection< ST > Class Template Reference

## Detailed Description

### template<class ST> class shogun::CFeatureSelection< ST >

Template class CFeatureSelection, base class for all feature selection preprocessors which select a subset of features (dimensions in the feature matrix) to achieve a specified number of dimensions, m_target_dim from a given set of features. This class showcases all feature selection algorithms via a generic interface. Supported algorithms are specified by the enum EFeatureSelectionAlgorithm which can be set via set_algorithm() call. Supported wrapper algorithms are.

• shogun::BACKWARD_ELIMINATION: apply_backward_elimination() method implements this algorithm. This runs inside a loop till it reaches m_target_dim. In each iteration, inside another loop that runs for all current dimensions we compute measures and store the scores for each current dimension. Based on those measures a number of features are removed at once.
• shogun::FORWARD_SELECTION: apply_forward_selection() method implements this algorithm. Inside a loop it adds selected features to an empty feature set till it reaches m_target_dim. In each iteration, inside another loop that runs for all current dimensions we compute measures and store the scores for each current dimension. Based on those measures a number of features are removed from the original feature set and added to the new feature set.

Since all these algorithm cannot be applied for all the feature selection approaches, the method set_algorithm() is kept abstract which is defined in the subclasses as appropriate.

The apply() method acts as a wrapper which decides which above methods to call based on the algorithm specified by m_algorithm. This method makes a deep copy of the original feature object using CSGObject::clone and then performs feature selection on it. The actual memory requirement depends on how copying a dimension subset is handled in CFeatures::copy_dimension_subset implementation.

For computing the measures that are used to rank the features for feature selection task, it relies on an abstract method compute_measures() which is defined in the subclasses.

Due to the difference in the measure, the removal policy for features can be different which is specified by the EFeatureRemovalPolicy enum and can be set by set_policy() call. The supported policies are

Note that not all policies can be adapted for a specific feature seleciton approaches. In general, in classes where feature selection is performed by removing the features which correspond to lowest measure, the policies shogun::N_SMALLEST and shogun::PERCENTILE_SMALLEST are appropriate. When features corresponding to highest measures are removed (e.g. training error in a cross-validation scenario), shogun::N_LARGEST and shogun::PERCENTILE_LARGEST are applicable. Therefore, set_policy() is kept abstract and subclasses define this to allow specific policies to be set.

Removal of features in each iteration is handled by an abstract method remove_feats() that removes a set of features at once based on the ranks of the features on the measure. Internally this method also updates a subset stack to keep track of the selected features. After calling apply(), the indices of the original features that are selected can be obtained by calling get_selected_feats() method. Please note that the selected features are always kept in the original order.

Some of the methods are for internal purpose and are not exposed to the public API. For example,

• method precompute() is provided which is intended to be overridden in the subclasses to perform specific tasks that can be completed beforehand in the feature selection algorithms. For example, see CKernelDependenceMaximization.
• method adapt_params() is also overridden in the subclasses which tunes the parameters based on current features that are then used to compute the measure.

Definition at line 139 of file FeatureSelection.h.

Inheritance diagram for CFeatureSelection< ST >:
[legend]

## Public Member Functions

CFeatureSelection ()
virtual ~CFeatureSelection ()
virtual CFeaturesapply (CFeatures *features)
virtual float64_t compute_measures (CFeatures *features, index_t idx)=0
virtual CFeaturesremove_feats (CFeatures *features, SGVector< index_t > argsorted)=0
SGVector< index_tget_selected_feats ()
virtual EFeatureClass get_feature_class ()
virtual EFeatureType get_feature_type ()
virtual EPreprocessorType get_type () const
void set_target_dim (index_t target_dim)
index_t get_target_dim () const
virtual void set_algorithm (EFeatureSelectionAlgorithm algorithm)=0
EFeatureSelectionAlgorithm get_algorithm () const
virtual void set_policy (EFeatureRemovalPolicy policy)=0
EFeatureRemovalPolicy get_policy () const
void set_num_remove (index_t num_remove)
index_t get_num_remove () const
virtual void set_labels (CLabels *labels)
CLabelsget_labels () const
virtual void cleanup ()
virtual const char * get_name () const
template<>
EFeatureType get_feature_type ()
template<>
EFeatureType get_feature_type ()
template<>
EFeatureType get_feature_type ()
template<>
EFeatureType get_feature_type ()
template<>
EFeatureType get_feature_type ()
template<>
EFeatureType get_feature_type ()
template<>
EFeatureType get_feature_type ()
template<>
EFeatureType get_feature_type ()
template<>
EFeatureType get_feature_type ()
template<>
EFeatureType get_feature_type ()
template<>
EFeatureType get_feature_type ()
template<>
EFeatureType get_feature_type ()
template<>
EFeatureType get_feature_type ()
virtual bool init (CFeatures *features)=0
virtual CSGObjectshallow_copy () const
virtual CSGObjectdeep_copy () const
virtual bool is_generic (EPrimitiveType *generic) const
template<class T >
void set_generic ()
void unset_generic ()
virtual void print_serializable (const char *prefix="")
virtual bool save_serializable (CSerializableFile *file, const char *prefix="", int32_t param_version=Version::get_version_parameter())
virtual bool load_serializable (CSerializableFile *file, const char *prefix="", int32_t param_version=Version::get_version_parameter())
DynArray< TParameter * > * load_file_parameters (const SGParamInfo *param_info, int32_t file_version, CSerializableFile *file, const char *prefix="")
DynArray< TParameter * > * load_all_file_parameters (int32_t file_version, int32_t current_version, CSerializableFile *file, const char *prefix="")
void map_parameters (DynArray< TParameter * > *param_base, int32_t &base_version, DynArray< const SGParamInfo * > *target_param_infos)
void set_global_io (SGIO *io)
SGIOget_global_io ()
void set_global_parallel (Parallel *parallel)
Parallelget_global_parallel ()
void set_global_version (Version *version)
Versionget_global_version ()
SGStringList< char > get_modelsel_names ()
void print_modsel_params ()
char * get_modsel_param_descr (const char *param_name)
index_t get_modsel_param_index (const char *param_name)
void build_gradient_parameter_dictionary (CMap< TParameter *, CSGObject * > *dict)
virtual void update_parameter_hash ()
virtual bool parameter_hash_changed ()
virtual bool equals (CSGObject *other, float64_t accuracy=0.0, bool tolerant=false)
virtual CSGObjectclone ()

## Public Attributes

SGIOio
Parallelparallel
Versionversion
Parameterm_parameters
Parameterm_model_selection_parameters
ParameterMapm_parameter_map
uint32_t m_hash

## Protected Member Functions

virtual CFeaturesapply_backward_elimination (CFeatures *features)
virtual void precompute ()
index_t get_num_features (CFeatures *features) const
virtual TParametermigrate (DynArray< TParameter * > *param_base, const SGParamInfo *target)
virtual void one_to_one_migration_prepare (DynArray< TParameter * > *param_base, const SGParamInfo *target, TParameter *&replacement, TParameter *&to_migrate, char *old_name=NULL)
virtual void load_serializable_pre () throw (ShogunException)
virtual void load_serializable_post () throw (ShogunException)
virtual void save_serializable_pre () throw (ShogunException)
virtual void save_serializable_post () throw (ShogunException)

## Protected Attributes

index_t m_target_dim
EFeatureSelectionAlgorithm m_algorithm
EFeatureRemovalPolicy m_policy
index_t m_num_remove
CLabelsm_labels
CSubsetStackm_subset

## Constructor & Destructor Documentation

 CFeatureSelection ( )

Default constructor

Definition at line 42 of file FeatureSelection.cpp.

 ~CFeatureSelection ( )
virtual

Destructor

Definition at line 72 of file FeatureSelection.cpp.

## Member Function Documentation

 void adapt_params ( CFeatures * features )
protectedvirtual

Tunes the parameters which are required to compute the measure based on current features. Overridden in the subclasses. Here it does nothing.

Parameters
 features the features based on which parameters are needed to be tuned for computing measures

Definition at line 218 of file FeatureSelection.cpp.

 CFeatures * apply ( CFeatures * features )
virtual

Generic interface for applying the feature selection preprocessor. Acts as a wrapper which decides which actual method to call based on the algorithm specified.

Parameters
 features the input features
Returns
the result feature object after applying the preprocessor

Implements CPreprocessor.

Definition at line 172 of file FeatureSelection.cpp.

 CFeatures * apply_backward_elimination ( CFeatures * features )
protectedvirtual

Applies backward elimination algorithm for performing feature selection. After performing necessary precomputing (defined by subclasses), it iteratively eliminates a number of features based on a measure until target dimension is reached.

Parameters
 features the input features
Returns
the result feature object after applying the preprocessor

Definition at line 86 of file FeatureSelection.cpp.

 void build_gradient_parameter_dictionary ( CMap< TParameter *, CSGObject * > * dict )
inherited

Builds a dictionary of all parameters in SGObject as well of those of SGObjects that are parameters of this object. Dictionary maps parameters to the objects that own them.

Parameters
 dict dictionary of parameters to be built.

Definition at line 1243 of file SGObject.cpp.

 void cleanup ( )
virtual

performs cleanup

Implements CPreprocessor.

Definition at line 80 of file FeatureSelection.cpp.

 CSGObject * clone ( )
virtualinherited

Creates a clone of the current object. This is done via recursively traversing all parameters, which corresponds to a deep copy. Calling equals on the cloned object always returns true although none of the memory of both objects overlaps.

Returns
an identical copy of the given object, which is disjoint in memory. NULL if the clone fails. Note that the returned object is SG_REF'ed

Definition at line 1360 of file SGObject.cpp.

 virtual float64_t compute_measures ( CFeatures * features, index_t idx )
pure virtual

Abstract method that is defined in the subclasses to compute the measures for the provided features based on which feature selection is performed.

Parameters
 features the features on which the measure has to be computed idx the index that decides which features should we compute the measure on
Returns
the measure based on which features are selected

Implemented in CDependenceMaximization.

 CSGObject * deep_copy ( ) const
virtualinherited

A deep copy. All the instance variables will also be copied.

Definition at line 200 of file SGObject.cpp.

 bool equals ( CSGObject * other, float64_t accuracy = 0.0, bool tolerant = false )
virtualinherited

Recursively compares the current SGObject to another one. Compares all registered numerical parameters, recursion upon complex (SGObject) parameters. Does not compare pointers!

May be overwritten but please do with care! Should not be necessary in most cases.

Parameters
 other object to compare with accuracy accuracy to use for comparison (optional) tolerant allows linient check on float equality (within accuracy)
Returns
true if all parameters were equal, false if not

Definition at line 1264 of file SGObject.cpp.

 EFeatureSelectionAlgorithm get_algorithm ( ) const
Returns
the feature removal algorithm being used

Definition at line 282 of file FeatureSelection.cpp.

 EFeatureClass get_feature_class ( )
virtual
Returns
the feature class, shogun::C_ANY

Implements CPreprocessor.

Definition at line 321 of file FeatureSelection.cpp.

 virtual EFeatureType get_feature_type ( )
virtual
Returns
feature type

Implements CPreprocessor.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 333 of file FeatureSelection.cpp.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 339 of file FeatureSelection.cpp.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 345 of file FeatureSelection.cpp.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 351 of file FeatureSelection.cpp.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 357 of file FeatureSelection.cpp.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 363 of file FeatureSelection.cpp.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 369 of file FeatureSelection.cpp.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 375 of file FeatureSelection.cpp.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 381 of file FeatureSelection.cpp.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 387 of file FeatureSelection.cpp.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 393 of file FeatureSelection.cpp.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 399 of file FeatureSelection.cpp.

 EFeatureType get_feature_type ( )
virtual
Returns
type of objects preprocessor can deal with

Implements CPreprocessor.

Definition at line 405 of file FeatureSelection.cpp.

 SGIO * get_global_io ( )
inherited

get the io object

Returns
io object

Definition at line 237 of file SGObject.cpp.

 Parallel * get_global_parallel ( )
inherited

get the parallel object

Returns
parallel object

Definition at line 278 of file SGObject.cpp.

 Version * get_global_version ( )
inherited

get the version object

Returns
version object

Definition at line 291 of file SGObject.cpp.

 CLabels * get_labels ( ) const
Returns
the labels

Definition at line 314 of file FeatureSelection.cpp.

 SGStringList< char > get_modelsel_names ( )
inherited
Returns
vector of names of all parameters which are registered for model selection

Definition at line 1135 of file SGObject.cpp.

 char * get_modsel_param_descr ( const char * param_name )
inherited

Returns description of a given parameter string, if it exists. SG_ERROR otherwise

Parameters
 param_name name of the parameter
Returns
description of the parameter

Definition at line 1159 of file SGObject.cpp.

 index_t get_modsel_param_index ( const char * param_name )
inherited

Returns index of model selection parameter with provided index

Parameters
 param_name name of model selection parameter
Returns
index of model selection parameter with provided name, -1 if there is no such

Definition at line 1172 of file SGObject.cpp.

 virtual const char* get_name ( ) const
virtual
Returns
the class name

Implements CSGObject.

Reimplemented in CDependenceMaximization, CBAHSIC, and CKernelDependenceMaximization.

Definition at line 254 of file FeatureSelection.h.

 index_t get_num_features ( CFeatures * features ) const
protected

Returns the number of features of the provided feature object. Since the number of features doesn't make sense for all types of features, this helper method checks whether obtaining a num_features is possible and then calls get_num_features() on those features after proper type-cast

Parameters
 features the feature object
Returns
the number of features

Definition at line 240 of file FeatureSelection.cpp.

 index_t get_num_remove ( ) const
Returns
number or percentage of features removed in each iteration

Definition at line 300 of file FeatureSelection.cpp.

 EFeatureRemovalPolicy get_policy ( ) const
Returns
the feature removal policy being used

Definition at line 288 of file FeatureSelection.cpp.

 SGVector< index_t > get_selected_feats ( )
Returns
indices of selected features

Definition at line 223 of file FeatureSelection.cpp.

 index_t get_target_dim ( ) const
Returns
the target dimension

Definition at line 276 of file FeatureSelection.cpp.

 EPreprocessorType get_type ( ) const
virtual
Returns
the preprocessor type

Implements CPreprocessor.

Reimplemented in CBAHSIC.

Definition at line 327 of file FeatureSelection.cpp.

 virtual bool init ( CFeatures * features )
pure virtualinherited

initialize preprocessor with features

 bool is_generic ( EPrimitiveType * generic ) const
virtualinherited

If the SGSerializable is a class template then TRUE will be returned and GENERIC is set to the type of the generic.

Parameters
 generic set to the type of the generic if returning TRUE
Returns
TRUE if a class template.

Definition at line 297 of file SGObject.cpp.

 DynArray< TParameter * > * load_all_file_parameters ( int32_t file_version, int32_t current_version, CSerializableFile * file, const char * prefix = "" )
inherited

maps all parameters of this instance to the provided file version and loads all parameter data from the file into an array, which is sorted (basically calls load_file_parameter(...) for all parameters and puts all results into a sorted array)

Parameters
 file_version parameter version of the file current_version version from which mapping begins (you want to use Version::get_version_parameter() for this in most cases) file file to load from prefix prefix for members
Returns
(sorted) array of created TParameter instances with file data

Definition at line 704 of file SGObject.cpp.

 DynArray< TParameter * > * load_file_parameters ( const SGParamInfo * param_info, int32_t file_version, CSerializableFile * file, const char * prefix = "" )
inherited

loads some specified parameters from a file with a specified version The provided parameter info has a version which is recursively mapped until the file parameter version is reached. Note that there may be possibly multiple parameters in the mapping, therefore, a set of TParameter instances is returned

Parameters
 param_info information of parameter file_version parameter version of the file, must be <= provided parameter version file file to load from prefix prefix for members
Returns
new array with TParameter instances with the attached data

Definition at line 545 of file SGObject.cpp.

 bool load_serializable ( CSerializableFile * file, const char * prefix = "", int32_t param_version = Version::get_version_parameter() )
virtualinherited

Load this object from file. If it will fail (returning FALSE) then this object will contain inconsistent data and should not be used!

Parameters
 file where to load from prefix prefix for members param_version (optional) a parameter version different to (this is mainly for testing, better do not use)
Returns
TRUE if done, otherwise FALSE

Definition at line 374 of file SGObject.cpp.

 void load_serializable_post ( ) throw (ShogunException)
protectedvirtualinherited

Can (optionally) be overridden to post-initialize some member variables which are not PARAMETER::ADD'ed. Make sure that at first the overridden method BASE_CLASS::LOAD_SERIALIZABLE_POST is called.

Exceptions
 ShogunException will be thrown if an error occurs.

Definition at line 1062 of file SGObject.cpp.

 void load_serializable_pre ( ) throw (ShogunException)
protectedvirtualinherited

Can (optionally) be overridden to pre-initialize some member variables which are not PARAMETER::ADD'ed. Make sure that at first the overridden method BASE_CLASS::LOAD_SERIALIZABLE_PRE is called.

Exceptions
 ShogunException will be thrown if an error occurs.

Definition at line 1057 of file SGObject.cpp.

 void map_parameters ( DynArray< TParameter * > * param_base, int32_t & base_version, DynArray< const SGParamInfo * > * target_param_infos )
inherited

Takes a set of TParameter instances (base) with a certain version and a set of target parameter infos and recursively maps the base level wise to the current version using CSGObject::migrate(...). The base is replaced. After this call, the base version containing parameters should be of same version/type as the initial target parameter infos. Note for this to work, the migrate methods and all the internal parameter mappings have to match

Parameters
 param_base set of TParameter instances that are mapped to the provided target parameter infos base_version version of the parameter base target_param_infos set of SGParamInfo instances that specify the target parameter base

Definition at line 742 of file SGObject.cpp.

 TParameter * migrate ( DynArray< TParameter * > * param_base, const SGParamInfo * target )
protectedvirtualinherited

creates a new TParameter instance, which contains migrated data from the version that is provided. The provided parameter data base is used for migration, this base is a collection of all parameter data of the previous version. Migration is done FROM the data in param_base TO the provided param info Migration is always one version step. Method has to be implemented in subclasses, if no match is found, base method has to be called.

If there is an element in the param_base which equals the target, a copy of the element is returned. This represents the case when nothing has changed and therefore, the migrate method is not overloaded in a subclass

Parameters
 param_base set of TParameter instances to use for migration target parameter info for the resulting TParameter
Returns
a new TParameter instance with migrated data from the base of the type which is specified by the target parameter

Definition at line 949 of file SGObject.cpp.

 void one_to_one_migration_prepare ( DynArray< TParameter * > * param_base, const SGParamInfo * target, TParameter *& replacement, TParameter *& to_migrate, char * old_name = NULL )
protectedvirtualinherited

This method prepares everything for a one-to-one parameter migration. One to one here means that only ONE element of the parameter base is needed for the migration (the one with the same name as the target). Data is allocated for the target (in the type as provided in the target SGParamInfo), and a corresponding new TParameter instance is written to replacement. The to_migrate pointer points to the single needed TParameter instance needed for migration. If a name change happened, the old name may be specified by old_name. In addition, the m_delete_data flag of to_migrate is set to true. So if you want to migrate data, the only thing to do after this call is converting the data in the m_parameter fields. If unsure how to use - have a look into an example for this. (base_migration_type_conversion.cpp for example)

Parameters
 param_base set of TParameter instances to use for migration target parameter info for the resulting TParameter replacement (used as output) here the TParameter instance which is returned by migration is created into to_migrate the only source that is used for migration old_name with this parameter, a name change may be specified

Definition at line 889 of file SGObject.cpp.

 bool parameter_hash_changed ( )
virtualinherited
Returns
whether parameter combination has changed since last update

Definition at line 263 of file SGObject.cpp.

 void precompute ( )
protectedvirtual

Performs the tasks which can be computed beforehand before the actual algorithm begins. This method is overridden in the subclasses. Here it does nothing.

Reimplemented in CKernelDependenceMaximization.

Definition at line 213 of file FeatureSelection.cpp.

 void print_modsel_params ( )
inherited

prints all parameter registered for model selection and their type

Definition at line 1111 of file SGObject.cpp.

 void print_serializable ( const char * prefix = "" )
virtualinherited

prints registered parameters out

Parameters
 prefix prefix for members

Definition at line 309 of file SGObject.cpp.

 virtual CFeatures* remove_feats ( CFeatures * features, SGVector< index_t > argsorted )
pure virtual

Abstract method which is defined in the subclasses to handle the removal of features based on removal policy (see class documentation). This also updates the subset internally for selected features.

Parameters
 features the features object from which specific features has to be removed argsorted the argsorted features based on their measures, entry at 0 being the index of the feature corresponding to the smallest measure.
Returns
the feature object after removal of features based on the policy

Implemented in CDependenceMaximization.

 bool save_serializable ( CSerializableFile * file, const char * prefix = "", int32_t param_version = Version::get_version_parameter() )
virtualinherited

Save this object to file.

Parameters
 file where to save the object; will be closed during returning if PREFIX is an empty string. prefix prefix for members param_version (optional) a parameter version different to (this is mainly for testing, better do not use)
Returns
TRUE if done, otherwise FALSE

Definition at line 315 of file SGObject.cpp.

 void save_serializable_post ( ) throw (ShogunException)
protectedvirtualinherited

Can (optionally) be overridden to post-initialize some member variables which are not PARAMETER::ADD'ed. Make sure that at first the overridden method BASE_CLASS::SAVE_SERIALIZABLE_POST is called.

Exceptions
 ShogunException will be thrown if an error occurs.

Reimplemented in CKernel.

Definition at line 1072 of file SGObject.cpp.

 void save_serializable_pre ( ) throw (ShogunException)
protectedvirtualinherited

Can (optionally) be overridden to pre-initialize some member variables which are not PARAMETER::ADD'ed. Make sure that at first the overridden method BASE_CLASS::SAVE_SERIALIZABLE_PRE is called.

Exceptions
 ShogunException will be thrown if an error occurs.

Definition at line 1067 of file SGObject.cpp.

 virtual void set_algorithm ( EFeatureSelectionAlgorithm algorithm )
pure virtual

Abstract method which is overridden in the subclasses to set accepted feature selection algorithm

Parameters
 algorithm the feature selection algorithm to use

Implemented in CDependenceMaximization, CKernelDependenceMaximization, and CBAHSIC.

 void set_generic< complex128_t > ( )
inherited

set generic type to T

Definition at line 42 of file SGObject.cpp.

 void set_global_io ( SGIO * io )
inherited

set the io object

Parameters
 io io object to use

Definition at line 230 of file SGObject.cpp.

 void set_global_parallel ( Parallel * parallel )
inherited

set the parallel object

Parameters
 parallel parallel object to use

Definition at line 243 of file SGObject.cpp.

 void set_global_version ( Version * version )
inherited

set the version object

Parameters
 version version object to use

Definition at line 284 of file SGObject.cpp.

 void set_labels ( CLabels * labels )
virtual

Setter for labels. This method may be overridden in subclasses if necessary to set some additional parameters associated with it. For example, in CDependenceMaximization, we need a feature instance of the labels which is used in the estimator. So this method is overridden there to internally convert the labels to a dense feature object in this set call only

Parameters
 labels the labels

Reimplemented in CDependenceMaximization.

Definition at line 306 of file FeatureSelection.cpp.

 void set_num_remove ( index_t num_remove )

Use this method to set the number or percentile of features to be removed in each iteration.

Parameters
 num_remove number or percentage of features to be removed in each iteration

Definition at line 294 of file FeatureSelection.cpp.

 virtual void set_policy ( EFeatureRemovalPolicy policy )
pure virtual

Abstract method which is overridden in the subclasses to set accepted feature removal policies based on the measure they use

Parameters
 policy the feature removal policy

Implemented in CDependenceMaximization.

 void set_target_dim ( index_t target_dim )
Parameters
 target_dim the target dimension to achieve

Definition at line 270 of file FeatureSelection.cpp.

 CSGObject * shallow_copy ( ) const
virtualinherited

A shallow copy. All the SGObject instance variables will be simply assigned and SG_REF-ed.

Reimplemented in CGaussianKernel.

Definition at line 194 of file SGObject.cpp.

 void unset_generic ( )
inherited

unset generic type

this has to be called in classes specializing a template class

Definition at line 304 of file SGObject.cpp.

 void update_parameter_hash ( )
virtualinherited

Updates the hash of current parameter combination

Definition at line 250 of file SGObject.cpp.

## Member Data Documentation

 SGIO* io
inherited

io

Definition at line 496 of file SGObject.h.

 EFeatureSelectionAlgorithm m_algorithm
protected

Wrapper algorithm for feature selection

Definition at line 302 of file FeatureSelection.h.

inherited

parameters wrt which we can compute gradients

Definition at line 511 of file SGObject.h.

 uint32_t m_hash
inherited

Hash of parameter values

Definition at line 517 of file SGObject.h.

 CLabels* m_labels
protected

The labels for the feature vectors

Definition at line 316 of file FeatureSelection.h.

 Parameter* m_model_selection_parameters
inherited

model selection parameters

Definition at line 508 of file SGObject.h.

 index_t m_num_remove
protected

Number or percentage of features to be removed. When the policy is set as shogun::N_SMALLEST or shogun::N_LARGEST, this number decides how many features in an iteration. For shogun::PERCENTILE_SMALLEST or shogun::PERCENTILE_LARGEST, this decides the percentage of current number of features to be removed in each iteration

Definition at line 313 of file FeatureSelection.h.

 ParameterMap* m_parameter_map
inherited

map for different parameter versions

Definition at line 514 of file SGObject.h.

 Parameter* m_parameters
inherited

parameters

Definition at line 505 of file SGObject.h.

 EFeatureRemovalPolicy m_policy
protected

Feature removal policy

Definition at line 305 of file FeatureSelection.h.

 CSubsetStack* m_subset
protected

The indices of features that are selected

Definition at line 319 of file FeatureSelection.h.

 index_t m_target_dim
protected

Target dimension

Definition at line 299 of file FeatureSelection.h.

 Parallel* parallel
inherited

parallel

Definition at line 499 of file SGObject.h.

 Version* version
inherited

version

Definition at line 502 of file SGObject.h.

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

SHOGUN Machine Learning Toolbox - Documentation