Inheritance diagram for faiss::PCAMatrix:

Public Member Functions
	PCAMatrix (int d_in=0, int d_out=0, float eigen_power=0, bool random_rotation=false)

virtual void	train (Index::idx_t n, const float *x) override

virtual void	reverse_transform (idx_t n, const float xt, float x) const override

void	copy_from (const PCAMatrix &other)
	copy pre-trained PCA matrix

void	prepare_Ab ()
	called after mean, PCAMat and eigenvalues are computed

Public Member Functions inherited from faiss::LinearTransform
	LinearTransform (int d_in=0, int d_out=0, bool have_bias=false)
	both d_in > d_out and d_out < d_in are supported

virtual void	apply_noalloc (idx_t n, const float x, float xt) const
	same as apply, but result is pre-allocated

void	transform_transpose (idx_t n, const float y, float x) const

const float *	maybe_subsample_train_set (Index::idx_t n, const float x)

Public Member Functions inherited from faiss::VectorTransform
	VectorTransform (int d_in=0, int d_out=0)
	! output dimension

float *	apply (idx_t n, const float *x) const

Public Attributes
float	eigen_power

bool	random_rotation
	random rotation after PCA

int	balanced_bins
	try to distribute output eigenvectors in this many bins

std::vector< float >	mean
	Mean, size d_in.

std::vector< float >	eigenvalues
	eigenvalues of covariance matrix (= squared singular values)

std::vector< float >	PCAMat
	PCA matrix, size d_in * d_in.

Public Attributes inherited from faiss::LinearTransform
bool	have_bias

std::vector< float >	A
	! whether to use the bias term More...

std::vector< float >	b
	bias vector, size d_out

size_t	max_points_per_d

bool	verbose

Public Attributes inherited from faiss::VectorTransform
int	d_in

int	d_out
	! input dimension

bool	is_trained

Additional Inherited Members
Public Types inherited from faiss::VectorTransform
typedef Index::idx_t	idx_t

Detailed Description

Applies a principal component analysis on a set of vectors, with optionally whitening and random rotation.

Definition at line 136 of file VectorTransform.h.

Member Function Documentation

void PCAMatrix::reverse_transform	(	idx_t	n,
		const float *	xt,
		float *	x
	)		const

overridevirtual

reverse transformation. May not be implemented or may return approximate result

Definition at line 444 of file VectorTransform.cpp.

overridevirtual

Perform training on a representative set of vectors. Does nothing by default.

Parameters

n	nb of training vectors
x	training vecors, size n * d

Definition at line 227 of file VectorTransform.cpp.

float faiss::PCAMatrix::eigen_power

after transformation the components are multiplied by eigenvalues^eigen_power

=0: no whitening =-2: full whitening

Definition at line 144 of file VectorTransform.h.

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