Prototype

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

tgexc( const fortran_bool_t wantq, const fortran_bool_t wantz,
        MatrixA& a, MatrixB& b, MatrixQ& q, MatrixZ& z,
        int_t& ifst, int_t& ilst );

tgexc( const fortran_bool_t wantq, const fortran_bool_t wantz,
        MatrixA& a, MatrixB& b, MatrixQ& q, MatrixZ& z,
        const int_t ifst, int_t& ilst );

Description

tgexc (short for $FRIENDLY_NAME) provides a C++ interface to LAPACK routines STGEXC, DTGEXC, CTGEXC, and ZTGEXC. tgexc reorders the generalized Schur decomposition of a complex matrix pair (A,B), using an unitary equivalence transformation (A, B) := Q * (A, B) * Z', so that the diagonal block of (A, B) with row index IFST is moved to row ILST.

(A, B) must be in generalized Schur canonical form, that is, A and B are both upper triangular.

Optionally, the matrices Q and Z of generalized Schur vectors are updated.

Q(in) * A(in) * Z(in)' = Q(out) * A(out) * Z(out)' Q(in) * B(in) * Z(in)' = Q(out) * B(out) * Z(out)'

The selection of the LAPACK routine is done during compile-time, and is determined by the type of values contained in type MatrixA. The type of values is obtained through the value_type meta-function typename value_type<MatrixA>::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/tgexc.hpp.

Parameters or Requirements on Types

Complexity

Example

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

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

this will output

[5] 0 1 2 3 4 5

Notes

See Also