Public Member Functions | Protected Attributes

CPCACut Class Reference


Detailed Description

Preprocessor PCACut performs principial component analysis on the input vectors and keeps only the n eigenvectors with eigenvalues above a certain threshold.

On preprocessing the stored covariance matrix is used to project vectors into eigenspace only returning vectors of reduced dimension n. Optional whitening is performed.

This is only useful if the dimensionality of the data is rather low, as the covariance matrix is of size num_feat*num_feat. Note that vectors don't have to have zero mean as it is substracted.

Definition at line 39 of file PCACut.h.

Inheritance diagram for CPCACut:
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List of all members.

Public Member Functions

 CPCACut (int32_t do_whitening=0, float64_t thresh=1e-6)
virtual ~CPCACut ()
virtual bool init (CFeatures *f)
 initialize preprocessor from features
virtual void cleanup ()
 cleanup
virtual float64_tapply_to_feature_matrix (CFeatures *f)
virtual float64_tapply_to_feature_vector (float64_t *f, int32_t &len)
virtual const char * get_name ()

Protected Attributes

double * T
int32_t num_dim
int32_t num_old_dim
float64_tmean
bool initialized
 true when already initialized
int32_t do_whitening
float64_t thresh

Constructor & Destructor Documentation

CPCACut ( int32_t  do_whitening = 0,
float64_t  thresh = 1e-6 
)

constructor

Parameters:
do_whitening do whitening
thresh threshold

Definition at line 30 of file PCACut.cpp.

~CPCACut (  )  [virtual]

Definition at line 36 of file PCACut.cpp.


Member Function Documentation

float64_t * apply_to_feature_matrix ( CFeatures f  )  [virtual]

apply preproc on feature matrix result in feature matrix return pointer to feature_matrix, i.e. f->get_feature_matrix();

Implements CSimplePreProc< float64_t >.

Definition at line 186 of file PCACut.cpp.

float64_t * apply_to_feature_vector ( float64_t f,
int32_t &  len 
) [virtual]

apply preproc on single feature vector result in feature matrix

Implements CSimplePreProc< float64_t >.

Definition at line 228 of file PCACut.cpp.

void cleanup (  )  [virtual]

cleanup

initialize preprocessor from features

Implements CPreProc.

Definition at line 177 of file PCACut.cpp.

virtual const char* get_name (  )  [virtual]
Returns:
object name

Definition at line 65 of file PCACut.h.

bool init ( CFeatures f  )  [virtual]

initialize preprocessor from features

compute mean

A = 1.0*xy^T+A blas

Implements CPreProc.

Definition at line 43 of file PCACut.cpp.


Member Data Documentation

int32_t do_whitening [protected]

do whitening

Definition at line 81 of file PCACut.h.

bool initialized [protected]

true when already initialized

Definition at line 78 of file PCACut.h.

float64_t* mean [protected]

mean

Definition at line 75 of file PCACut.h.

int32_t num_dim [protected]

num dim

Definition at line 71 of file PCACut.h.

int32_t num_old_dim [protected]

num old dim

Definition at line 73 of file PCACut.h.

double* T [protected]

T

Definition at line 69 of file PCACut.h.

float64_t thresh [protected]

thresh

Definition at line 83 of file PCACut.h.


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