RWSymEigDecomp< T1 > Class Template Reference

Encapsulates the eigenvalues and eigenvectors of a symmetric matrix. More...

#include <rw/lapack/symeig.h>

Public Member Functions
	RWSymEigDecomp ()
	RWSymEigDecomp (const RWSymEigDecomp< TypeT > &A)
	RWSymEigDecomp (const RWSymMat< TypeT > &A, bool computeVecs=true)
	RWSymEigDecomp (const RWSymBandMat< TypeT > &A, bool computeVecs=true)
	More...
unsigned	cols () const
TypeT	eigenValue (int i) const
const RWMathVec< TypeT >	eigenValues () const
const RWMathVec< TypeT >	eigenVector (int i) const
const RWGenMat< TypeT >	eigenVectors () const
void	factor (const RWSymMat< TypeT > &A, bool computeVecs=true)
void	factor (const RWSymBandMat< TypeT > &A, bool computeVecs=true)
	More...
bool	fail () const
bool	good () const
bool	inaccurate () const
unsigned	numEigenValues () const
unsigned	numEigenVectors () const
RWSymEigDecomp< TypeT > &	operator= (const RWSymEigDecomp< TypeT > &A)
unsigned	rows () const

Detailed Description

template<class T1>
class RWSymEigDecomp< T1 >

The class RWSymEigDecomp<T> encapsulates the eigenvalues and eigenvectors of a symmetric matrix. You can construct an eigenvalue decomposition object in two ways:

• Use the decomposition class constructor. This has the advantage of simplicity, but allows only limited control over the computation. Your only choice is whether or not to compute eigenvectors.
• Use an eigenvalue server object. This gives you more precise control over the computation. See RWSymEigServer<T> for details.

Synopsis

#include <rw/lapack/symeig.h>    // RWSymEigDecomp<T>

RWSymEigDecomp<double> eig(A);   // A is an RWSymMat<double>

Example

#include <iostream>
#include <rw/lapack/symeig.h>

int main()
{
    RWSymMat<double> A;
    std::cin >> A;
    RWSymEigDecomp<double> eig(A);
    std::cout << "eigenvalues: " << eig.eigenValues() << std::endl;
    std::cout << "eigenvectors: " << eig.eigenVectors() << std::endl;

    return 0;
}

Constructor & Destructor Documentation

template<class T1>

RWSymEigDecomp< T1 >::RWSymEigDecomp

(

)

Default constructor. Builds a decomposition of a 0 x 0 matrix.

template<class T1>

RWSymEigDecomp< T1 >::RWSymEigDecomp

(

const RWSymEigDecomp< TypeT > &

A

)

Copy and precision conversion constructor. Where possible, data is referenced for efficiency.

template<class T1>

RWSymEigDecomp< T1 >::RWSymEigDecomp	(	const RWSymMat< TypeT > &	A,
		bool	computeVecs = true
	)

Constructs a representation of the eigenvalues and eigenvectors of the matrix A. The boolean parameter controls whether eigenvectors are computed.

template<class T1>

RWSymEigDecomp< T1 >::RWSymEigDecomp	(	const RWSymBandMat< TypeT > &	A,
		bool	computeVecs = true
	)

Constructs a representation of the eigenvalues and eigenvectors of the matrix A. The boolean parameter controls whether eigenvectors are computed.

Member Function Documentation

template<class T1>

unsigned RWSymEigDecomp< T1 >::cols ( ) const

inline

Returns the number of columns in the decomposed matrix.

template<class T1>

TypeT RWSymEigDecomp< T1 >::eigenValue

(

int

i

)

const

Returns the i ^th eigenvalue.

template<class T1>

const RWMathVec<TypeT> RWSymEigDecomp< T1 >::eigenValues ( ) const

inline

Returns a vector of all computed eigenvalues.

template<class T1>

const RWMathVec<TypeT> RWSymEigDecomp< T1 >::eigenVector

(

int

i

)

const

Returns the i ^th eigenvector.

template<class T1>

const RWGenMat<TypeT> RWSymEigDecomp< T1 >::eigenVectors ( ) const

inline

Returns a matrix whose columns are the eigenvectors.

template<class T1>

void RWSymEigDecomp< T1 >::factor	(	const RWSymMat< TypeT > &	A,
		bool	computeVecs = true
	)

Constructs a representation of the eigenvalues and eigenvectors of the matrix A. The boolean parameter controls whether eigenvectors are computed. The current contents of the decomposition are lost.

template<class T1>

void RWSymEigDecomp< T1 >::factor	(	const RWSymBandMat< TypeT > &	A,
		bool	computeVecs = true
	)

Constructs a representation of the eigenvalues and eigenvectors of the matrix A. The boolean parameter controls whether eigenvectors are computed. The current contents of the decomposition are lost.

template<class T1>

bool RWSymEigDecomp< T1 >::fail

(

)

const

Returns true if an eigenvalue or eigenvector that is supposed to be computed fails to be computed.

template<class T1>

bool RWSymEigDecomp< T1 >::good

(

)

const

Returns true if all desired eigenvalues and eigenvectors are successfully computed to full desired accuracy.

template<class T1>

bool RWSymEigDecomp< T1 >::inaccurate

(

)

const

Returns true if either an eigenvalue or eigenvector that is supposed to be computed fails to be computed, or some of the computed quantities are not computed to full desired accuracy.

template<class T1>

unsigned RWSymEigDecomp< T1 >::numEigenValues ( ) const

inline

Returns the number of eigenvalues in this object.

template<class T1>

unsigned RWSymEigDecomp< T1 >::numEigenVectors ( ) const

inline

Returns the number of eigenvectors in this object.

template<class T1>

RWSymEigDecomp<TypeT>& RWSymEigDecomp< T1 >::operator=

(

const RWSymEigDecomp< TypeT > &

A

)

Assigns this decomposition the passed value. The current contents of the decomposition are lost.

template<class T1>

unsigned RWSymEigDecomp< T1 >::rows ( ) const

inline

Returns the number of rows in the decomposed matrix.