vnl_sparse_symmetric_eigensystem Class Reference

#include <vnl_sparse_symmetric_eigensystem.h>

Detailed Description

Find the eigenvalues of a sparse symmetric matrix.

Solve the eigenproblem $A x = \lambda x$ , with $A$ symmetric and sparse. The block Lanczos algorithm is used to allow the recovery of a number of eigenvalue/eigenvector pairs from either end of the spectrum, to a required accuracy.

Uses the dnlaso routine from the LASO package of netlib.

Definition at line 29 of file vnl_sparse_symmetric_eigensystem.h.


Public Member Functions
	vnl_sparse_symmetric_eigensystem ()
	~vnl_sparse_symmetric_eigensystem ()
int	CalculateNPairs (vnl_sparse_matrix< double > &M, int n, bool smallest=true, long nfigures=10)
	Here is where the fortran converted code gets called.
vnl_vector< double >	get_eigenvector (int i) const
	Return a calculated eigenvector.
double	get_eigenvalue (int i) const
int	CalculateProduct (int n, int m, const double p, double q)
	Callback from solver to calculate the product A p.
int	SaveVectors (int n, int m, const double *q, int base)
	Callback to store vectors for dnlaso.
int	RestoreVectors (int n, int m, double *q, int base)
	Callback to restore vectors for dnlaso.
Protected Attributes
int	nvalues
vnl_vector< double > *	vectors
double *	values
vnl_sparse_matrix< double > *	mat
vcl_vector< double * >	temp_store

Constructor & Destructor Documentation

vnl_sparse_symmetric_eigensystem::vnl_sparse_symmetric_eigensystem ( )

Definition at line 59 of file vnl_sparse_symmetric_eigensystem.cxx.

vnl_sparse_symmetric_eigensystem::~vnl_sparse_symmetric_eigensystem ( )

Definition at line 64 of file vnl_sparse_symmetric_eigensystem.cxx.

Member Function Documentation

int vnl_sparse_symmetric_eigensystem::CalculateNPairs	(	vnl_sparse_matrix< double > &	M,
		int	n,
		bool	smallest = `true`,
		long	nfigures = `10`
	)

Here is where the fortran converted code gets called.

The sparse matrix M is assumed to be symmetric. The n smallest eigenvalues and their corresponding eigenvectors are calculated if smallest is true (the default). Otherwise the n largest eigenpairs are found. The accuracy of the eigenvalues is to nfigures decimal digits. Returns 0 if successful, non-zero otherwise.

Definition at line 80 of file vnl_sparse_symmetric_eigensystem.cxx.

vnl_vector< double > vnl_sparse_symmetric_eigensystem::get_eigenvector ( int i ) const

Return a calculated eigenvector.

Definition at line 265 of file vnl_sparse_symmetric_eigensystem.cxx.

double vnl_sparse_symmetric_eigensystem::get_eigenvalue ( int i ) const

Definition at line 271 of file vnl_sparse_symmetric_eigensystem.cxx.