Prototype

There are two prototypes of hsein available, please see below.

hsein( const Side side, const char eigsrc, const char initv,
        VectorSELECT& select, const MatrixH& h, VectorWR& wr,
        const VectorWI& wi, MatrixVL& vl, MatrixVR& vr,
        const int_t mm, int_t& m,
        VectorIFAILL& ifaill, VectorIFAILR& ifailr );

hsein( const Side side, const char eigsrc, const char initv,
        const VectorSELECT& select, const MatrixH& h, VectorW& w,
        MatrixVL& vl, MatrixVR& vr, const int_t mm,
        int_t& m, VectorIFAILL& ifaill, VectorIFAILR& ifailr );

Description

hsein (short for $FRIENDLY_NAME) provides a C++ interface to LAPACK routines SHSEIN, DHSEIN, CHSEIN, and ZHSEIN. hsein uses inverse iteration to find specified right and/or left eigenvectors of a complex upper Hessenberg matrix H.

The right eigenvector x and the left eigenvector y of the matrix H corresponding to an eigenvalue w are defined by:

H * x = w * x, y*h * H = w * y*h

where y**h denotes the conjugate transpose of the vector y.

The selection of the LAPACK routine is done during compile-time, and is determined by the type of values contained in type VectorSELECT. The type of values is obtained through the value_type meta-function typename value_type<VectorSELECT>::type. The dispatching table below illustrates to which specific routine the code path will be generated.

Definition

Defined in header boost/numeric/bindings/lapack/computational/hsein.hpp.

Parameters or Requirements on Types

Complexity

Example

#include <boost/numeric/bindings/lapack/computational/hsein.hpp>
using namespace boost::numeric::bindings;

lapack::hsein( x, y, z );

this will output

[5] 0 1 2 3 4 5

Notes

See Also