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CKernelIndependenceTest Class Reference

Detailed Description

Kernel independence test base class. Provides an interface for performing an independence test. Given samples \(Z=\{(x_i,y_i)\}_{i=1}^m\) from the joint distribution \(\textbf{P}_{xy}\), does the joint distribution factorize as \(\textbf{P}_{xy}=\textbf{P}_x\textbf{P}_y\), i.e. product of the marginals?

The null-hypothesis says yes, i.e. no dependence, the alternative hypothesis says no.

In this class, this is done using a single kernel for each of the two sets of samples

The class also re-implements the sample_null() method. If the underlying kernel is a custom one (precomputed), the rows and column of the kernel matrix for p is permuted using subsets. The computation falls back to CIndependenceTest::sample_null() otherwise, which requires to re-compute the kernel in each iteration via subsets on the features instead

Abstract base class.

Definition at line 65 of file KernelIndependenceTest.h.

Inheritance diagram for CKernelIndependenceTest:
Inheritance graph
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Public Member Functions

 CKernelIndependenceTest ()
 CKernelIndependenceTest (CKernel *kernel_p, CKernel *kernel_q, CFeatures *p, CFeatures *q)
virtual ~CKernelIndependenceTest ()
virtual SGVector< float64_tsample_null ()
virtual void set_kernel_p (CKernel *kernel_p)
virtual void set_kernel_q (CKernel *kernel_q)
virtual CKernelget_kernel_p ()
virtual CKernelget_kernel_q ()
virtual const char * get_name () const =0
virtual void set_p (CFeatures *p)
virtual void set_q (CFeatures *q)
virtual CFeaturesget_p ()
virtual CFeaturesget_q ()
virtual float64_t compute_statistic ()=0
virtual float64_t compute_p_value (float64_t statistic)
virtual float64_t compute_threshold (float64_t alpha)
virtual float64_t perform_test ()
bool perform_test (float64_t alpha)
virtual void set_num_null_samples (index_t num_null_samples)
virtual void set_null_approximation_method (ENullApproximationMethod null_approximation_method)
virtual EStatisticType get_statistic_type () const =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
Parameterm_gradient_parameters
ParameterMapm_parameter_map
uint32_t m_hash

Protected Member Functions

SGMatrix< float64_tget_kernel_matrix_K ()
SGMatrix< float64_tget_kernel_matrix_L ()
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

CKernelm_kernel_p
CKernelm_kernel_q
CFeaturesm_p
CFeaturesm_q
index_t m_num_null_samples
ENullApproximationMethod m_null_approximation_method

Constructor & Destructor Documentation

default constructor

Definition at line 39 of file KernelIndependenceTest.cpp.

CKernelIndependenceTest ( CKernel kernel_p,
CKernel kernel_q,
CFeatures p,
CFeatures q 
)

Constructor.

Initializes the kernels and features from the two distributions and SG_REFs them

Parameters
kernel_pkernel to use on samples from p
kernel_qkernel to use on samples from q
psamples from distribution p
qsamples from distribution q

Definition at line 45 of file KernelIndependenceTest.cpp.

destructor

Definition at line 58 of file KernelIndependenceTest.cpp.

Member Function Documentation

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
dictdictionary of parameters to be built.

Definition at line 1185 of file SGObject.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 1302 of file SGObject.cpp.

float64_t compute_p_value ( float64_t  statistic)
virtualinherited

computes a p-value based on current method for approximating the null-distribution. The p-value is the 1-p quantile of the null- distribution where the given statistic lies in. This method depends on the implementation of sample_null method which should be implemented in its sub-classes

Parameters
statisticstatistic value to compute the p-value for
Returns
p-value parameter statistic is the (1-p) percentile of the null distribution

Reimplemented in CQuadraticTimeMMD, CNOCCO, CStreamingMMD, CHSIC, and CTwoSampleTest.

Definition at line 71 of file HypothesisTest.cpp.

virtual float64_t compute_statistic ( )
pure virtualinherited
Returns
test statistic for the given data/parameters/methods

Implemented in CQuadraticTimeMMD, CNOCCO, CHSIC, CStreamingMMD, and CKernelTwoSampleTest.

float64_t compute_threshold ( float64_t  alpha)
virtualinherited

computes a threshold based on current method for approximating the null-distribution. The threshold is the value that a statistic has to have in ordner to reject the null-hypothesis. This method depends on the implementation of sample_null method which should be implemented in its sub-classes

Parameters
alphatest level to reject null-hypothesis
Returns
threshold for statistics to reject null-hypothesis

Reimplemented in CQuadraticTimeMMD, CStreamingMMD, CNOCCO, CHSIC, and CTwoSampleTest.

Definition at line 93 of file HypothesisTest.cpp.

CSGObject * deep_copy ( ) const
virtualinherited

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

Definition at line 146 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
otherobject to compare with
accuracyaccuracy to use for comparison (optional)
tolerantallows linient check on float equality (within accuracy)
Returns
true if all parameters were equal, false if not

Definition at line 1206 of file SGObject.cpp.

SGIO * get_global_io ( )
inherited

get the io object

Returns
io object

Definition at line 183 of file SGObject.cpp.

Parallel * get_global_parallel ( )
inherited

get the parallel object

Returns
parallel object

Definition at line 224 of file SGObject.cpp.

Version * get_global_version ( )
inherited

get the version object

Returns
version object

Definition at line 237 of file SGObject.cpp.

SGMatrix< float64_t > get_kernel_matrix_K ( )
protected
Returns
kernel matrix on samples from p. Distinguishes CustomKernels

Definition at line 157 of file KernelIndependenceTest.cpp.

SGMatrix< float64_t > get_kernel_matrix_L ( )
protected
Returns
kernel matrix on samples from q. Distinguishes CustomKernels

Definition at line 183 of file KernelIndependenceTest.cpp.

CKernel * get_kernel_p ( )
virtual

Getter for kernel for features from p, SG_REF'ed

Returns
kernel for features from p

Definition at line 145 of file KernelIndependenceTest.cpp.

CKernel * get_kernel_q ( )
virtual

Getter for kernel for features from q, SG_REF'ed

Returns
kernel for features from q

Definition at line 151 of file KernelIndependenceTest.cpp.

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

Definition at line 1077 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_namename of the parameter
Returns
description of the parameter

Definition at line 1101 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_namename of model selection parameter
Returns
index of model selection parameter with provided name, -1 if there is no such

Definition at line 1114 of file SGObject.cpp.

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

Implements CIndependenceTest.

Implemented in CNOCCO, and CHSIC.

CFeatures * get_p ( )
virtualinherited

Getter for features from p, SG_REF'ed

Returns
feature object from p

Definition at line 121 of file IndependenceTest.cpp.

CFeatures * get_q ( )
virtualinherited

Getter for features from q, SG_REF'ed

Returns
feature object from q

Definition at line 127 of file IndependenceTest.cpp.

virtual EStatisticType get_statistic_type ( ) const
pure virtualinherited

returns the statistic type of this test statistic

Implemented in CQuadraticTimeMMD, CNOCCO, CHSIC, and CLinearTimeMMD.

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

Definition at line 243 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_versionparameter version of the file
current_versionversion from which mapping begins (you want to use Version::get_version_parameter() for this in most cases)
filefile to load from
prefixprefix for members
Returns
(sorted) array of created TParameter instances with file data

Definition at line 648 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_infoinformation of parameter
file_versionparameter version of the file, must be <= provided parameter version
filefile to load from
prefixprefix for members
Returns
new array with TParameter instances with the attached data

Definition at line 489 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
filewhere to load from
prefixprefix 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 320 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
ShogunExceptionWill be thrown if an error occurres.

Reimplemented in CKernel, CWeightedDegreePositionStringKernel, CList, CAlphabet, CLinearHMM, CGaussianKernel, CInverseMultiQuadricKernel, CCircularKernel, and CExponentialKernel.

Definition at line 1004 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
ShogunExceptionWill be thrown if an error occurres.

Reimplemented in CDynamicArray< T >, CDynamicArray< float64_t >, CDynamicArray< float32_t >, CDynamicArray< int32_t >, CDynamicArray< char >, CDynamicArray< bool >, and CDynamicObjectArray.

Definition at line 999 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_baseset of TParameter instances that are mapped to the provided target parameter infos
base_versionversion of the parameter base
target_param_infosset of SGParamInfo instances that specify the target parameter base

Definition at line 686 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_baseset of TParameter instances to use for migration
targetparameter 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 893 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_baseset of TParameter instances to use for migration
targetparameter info for the resulting TParameter
replacement(used as output) here the TParameter instance which is returned by migration is created into
to_migratethe only source that is used for migration
old_namewith this parameter, a name change may be specified

Definition at line 833 of file SGObject.cpp.

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

Definition at line 209 of file SGObject.cpp.

float64_t perform_test ( )
virtualinherited

Performs the complete two-sample test on current data and returns a p-value.

This is a wrapper that calls compute_statistic first and then calls compute_p_value using the obtained statistic. In some statistic classes, it might be possible to compute statistic and p-value in one single run which is more efficient. Therefore, this method might be overwritten in subclasses.

The method for computing the p-value can be set via set_null_approximation_method().

Returns
p-value such that computed statistic is the (1-p) quantile of the estimated null distribution

Reimplemented in CStreamingMMD.

Definition at line 112 of file HypothesisTest.cpp.

bool perform_test ( float64_t  alpha)
inherited

Performs the complete two-sample test on current data and returns a binary answer wheter null hypothesis is rejected or not.

This is just a wrapper for the above perform_test() method that returns a p-value. If this p-value lies below the test level alpha, the null hypothesis is rejected.

Should not be overwritten in subclasses. (Therefore not virtual)

Parameters
alphatest level alpha.
Returns
true if null hypothesis is rejected and false otherwise

Definition at line 120 of file HypothesisTest.cpp.

void print_modsel_params ( )
inherited

prints all parameter registered for model selection and their type

Definition at line 1053 of file SGObject.cpp.

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

prints registered parameters out

Parameters
prefixprefix for members

Definition at line 255 of file SGObject.cpp.

SGVector< float64_t > sample_null ( )
virtual

shuffles the indeices that corresponds to the kernel entries of samples from p while accessing samples from q in the original order and computes the test statistic m_num_null_samples times. This version checks if a precomputed custom kernel is used, and, if so, just permutes the indices of the kernel corresponding to p instead of re-computing it in every iteration.

Returns
vector of all statistics

Reimplemented from CIndependenceTest.

Reimplemented in CNOCCO, and CHSIC.

Definition at line 75 of file KernelIndependenceTest.cpp.

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

Save this object to file.

Parameters
filewhere to save the object; will be closed during returning if PREFIX is an empty string.
prefixprefix 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 261 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
ShogunExceptionWill be thrown if an error occurres.

Reimplemented in CKernel.

Definition at line 1014 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
ShogunExceptionWill be thrown if an error occurres.

Reimplemented in CKernel, CDynamicArray< T >, CDynamicArray< float64_t >, CDynamicArray< float32_t >, CDynamicArray< int32_t >, CDynamicArray< char >, CDynamicArray< bool >, and CDynamicObjectArray.

Definition at line 1009 of file SGObject.cpp.

void set_generic< complex128_t > ( )
inherited

set generic type to T

Definition at line 38 of file SGObject.cpp.

void set_global_io ( SGIO io)
inherited

set the io object

Parameters
ioio object to use

Definition at line 176 of file SGObject.cpp.

void set_global_parallel ( Parallel parallel)
inherited

set the parallel object

Parameters
parallelparallel object to use

Definition at line 189 of file SGObject.cpp.

void set_global_version ( Version version)
inherited

set the version object

Parameters
versionversion object to use

Definition at line 230 of file SGObject.cpp.

void set_kernel_p ( CKernel kernel_p)
virtual

Setter for kernel for features from distribution p, SG_REFs it

Parameters
kernel_pkernel for features from p

Definition at line 129 of file KernelIndependenceTest.cpp.

void set_kernel_q ( CKernel kernel_q)
virtual

Setter for kernel for features from distribution q, SG_REFs it

Parameters
kernel_qkernel for features from q

Definition at line 137 of file KernelIndependenceTest.cpp.

void set_null_approximation_method ( ENullApproximationMethod  null_approximation_method)
virtualinherited

sets the method how to approximate the null-distribution

Parameters
null_approximation_methodmethod to use

Definition at line 60 of file HypothesisTest.cpp.

void set_num_null_samples ( index_t  num_null_samples)
virtualinherited

sets the number of permutation iterations for sample_null()

Parameters
num_null_sampleshow often permutation shall be done

Definition at line 66 of file HypothesisTest.cpp.

void set_p ( CFeatures p)
virtualinherited

Setter for features from distribution p, SG_REFs it

Parameters
pfeatures from p

Reimplemented in CNOCCO, and CHSIC.

Definition at line 105 of file IndependenceTest.cpp.

void set_q ( CFeatures q)
virtualinherited

Setter for features from distribution q, SG_REFs it

Parameters
qfeatures from q

Reimplemented in CNOCCO, and CHSIC.

Definition at line 113 of file IndependenceTest.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 140 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 250 of file SGObject.cpp.

void update_parameter_hash ( )
virtualinherited

Updates the hash of current parameter combination

Definition at line 196 of file SGObject.cpp.

Member Data Documentation

SGIO* io
inherited

io

Definition at line 461 of file SGObject.h.

Parameter* m_gradient_parameters
inherited

parameters wrt which we can compute gradients

Definition at line 476 of file SGObject.h.

uint32_t m_hash
inherited

Hash of parameter values

Definition at line 482 of file SGObject.h.

CKernel* m_kernel_p
protected

underlying kernel for p

Definition at line 137 of file KernelIndependenceTest.h.

CKernel* m_kernel_q
protected

underlying kernel for q

Definition at line 140 of file KernelIndependenceTest.h.

Parameter* m_model_selection_parameters
inherited

model selection parameters

Definition at line 473 of file SGObject.h.

ENullApproximationMethod m_null_approximation_method
protectedinherited

Defines how the the null distribution is approximated

Definition at line 177 of file HypothesisTest.h.

index_t m_num_null_samples
protectedinherited

number of iterations for sampling from null-distributions

Definition at line 174 of file HypothesisTest.h.

CFeatures* m_p
protectedinherited

samples of the distribution p

Definition at line 116 of file IndependenceTest.h.

ParameterMap* m_parameter_map
inherited

map for different parameter versions

Definition at line 479 of file SGObject.h.

Parameter* m_parameters
inherited

parameters

Definition at line 470 of file SGObject.h.

CFeatures* m_q
protectedinherited

samples of the distribution q

Definition at line 119 of file IndependenceTest.h.

Parallel* parallel
inherited

parallel

Definition at line 464 of file SGObject.h.

Version* version
inherited

version

Definition at line 467 of file SGObject.h.


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

SHOGUN Machine Learning Toolbox - Documentation