RWHessEigServer<T>

Module:  Linear Algebra   Group:  Nonsymmetric Eigenvalue Decomposition classes

Does not inherit

• Local Index
• Synopsis
• Description
• Example
• Public Constructor
• Public Member Functions
• Public Member Operators

Members

Balance() computeAllEigenVectors() computeLeftEigenVectors()

computeRightEigenVectors() operator()() permute()

RWHessEigServer() scale() selectEigenVectors()

#include <rw/lapack/eigsrv.h>

RWHessEigServer<double> server;
RWHessEigDecomp<double> deig = server(A); // A is an
                                  // RWGenMat<double>

The class RWHessEigServer<T> encapsulates Hessenberg decomposition eigenvalue servers. These servers are used to construct eigenvalue decomposition objects of type RWEigDecomp<T> from Hessenberg decompositions. The server can be configured to control which eigenvectors are computed, and other details of the computation. The eigenvectors are computed using inverse iteration. This is a good method to use when you need only a small number of the eigenvectors, perhaps less than 20%.

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

int main()
{
    RWGenMat<double> A; // input a matrix
    std::cin >> A;

    RWHessEigServer<double> server; // configure a server
    server.balance(false); // turn off balancing option
    server.selectEigenVectors(RWMathVec<int>("[1 2 3 8 9]"));
    
    RWHessEigDecomp<double> deig = server(A);
    return 0;
}

RWHessEigServer(bool computeLeftVecs=true,
          bool computeRightVecs=true,
          bool scale=true,
          bool permute=true);

Constructs a server. You can adjust some basic options at construction time, or adjust them later using member functions.

void
Balance(bool);

Controls whether to do permutation and scaling transformations (balancing) before computing the eigenvalue decomposition.

bool
computeAllEigenVectors() const;

Returns true if this server is configured to compute all the eigenvectors.

bool
computeLeftEigenVectors() const;

Returns whether or not this server is configured to compute the left eigenvectors.

bool
computeLeftEigenVectors(bool);

Configures whether or not left eigenvectors are to be computed.

bool
computeRightEigenVectors() const;

Returns whether or not this server is configured to compute the right eigenvectors.

bool
computeRightEigenVectors(bool);

Configures whether or not right eigenvectors are to be computed.

bool
scale() const;

Returns true if the server is configured to do a scaling transformation before computing the eigenvalues. Sometimes this transformation can result in more accurate eigenvalues.

void
scale(bool) const;

Configures whether or not to do a scaling transformation before computing the eigenvalues. Sometimes this transformation can result in more accurate eigenvalues.

void
selectEigenVectors(const RWMathVec<int>&);
void
selectEigenVectors(const RWSlice&);

Selects which eigenvectors are to be computed. This call causes the server to forget which eigenvectors were previously selected. With a real as opposed to complex eigenserver object, selecting either of a complex conjugate pair of eigenvalues causes both to be selected.

bool
permute() const;

Returns true if the server is configured to attempt a permutation before computing the eigenvalues. Sometimes this can result in less computation.

void
permute(bool) const;

Configures whether or not to do a permutation transformation before computing the eigenvalues. Sometimes this can result in less computation.

RWEigDecomp<T>   operator()(const RWGenMat<T>&);
RWEigDecomp<T>   operator()(const
                              RWBalanceDecomp<T>&);
RWEigDecomp<T>   operator()(const
                             RWHessenbergDecomp<T>&);

Computes an eigenvalue decomposition. The matrix to be decomposed can be represented as any of the above argument types.

© Copyright Rogue Wave Software, Inc. All Rights Reserved.
Rogue Wave and SourcePro are registered trademarks of Rogue Wave Software, Inc. in the United States and other countries. All other trademarks are the property of their respective owners.
Contact Rogue Wave about documentation or support issues.