SRC/zlaein.f(3)            Library Functions Manual            SRC/zlaein.f(3)

NAME
       SRC/zlaein.f

SYNOPSIS
   Functions/Subroutines
       subroutine zlaein (rightv, noinit, n, h, ldh, w, v, b, ldb, rwork,
           eps3, smlnum, info)
           ZLAEIN computes a specified right or left eigenvector of an upper
           Hessenberg matrix by inverse iteration.

Function/Subroutine Documentation
   subroutine zlaein (logical rightv, logical noinit, integer n, complex*16,
       dimension( ldh, * ) h, integer ldh, complex*16 w, complex*16,
       dimension( * ) v, complex*16, dimension( ldb, * ) b, integer ldb,
       double precision, dimension( * ) rwork, double precision eps3, double
       precision smlnum, integer info)
       ZLAEIN computes a specified right or left eigenvector of an upper
       Hessenberg matrix by inverse iteration.

       Purpose:


            ZLAEIN uses inverse iteration to find a right or left eigenvector
            corresponding to the eigenvalue W of a complex upper Hessenberg
            matrix H.

       Parameters
           RIGHTV

                     RIGHTV is LOGICAL
                     = .TRUE. : compute right eigenvector;
                     = .FALSE.: compute left eigenvector.

           NOINIT

                     NOINIT is LOGICAL
                     = .TRUE. : no initial vector supplied in V
                     = .FALSE.: initial vector supplied in V.

           N

                     N is INTEGER
                     The order of the matrix H.  N >= 0.

           H

                     H is COMPLEX*16 array, dimension (LDH,N)
                     The upper Hessenberg matrix H.

           LDH

                     LDH is INTEGER
                     The leading dimension of the array H.  LDH >= max(1,N).

           W

                     W is COMPLEX*16
                     The eigenvalue of H whose corresponding right or left
                     eigenvector is to be computed.

           V

                     V is COMPLEX*16 array, dimension (N)
                     On entry, if NOINIT = .FALSE., V must contain a starting
                     vector for inverse iteration; otherwise V need not be set.
                     On exit, V contains the computed eigenvector, normalized so
                     that the component of largest magnitude has magnitude 1; here
                     the magnitude of a complex number (x,y) is taken to be
                     |x| + |y|.

           B

                     B is COMPLEX*16 array, dimension (LDB,N)

           LDB

                     LDB is INTEGER
                     The leading dimension of the array B.  LDB >= max(1,N).

           RWORK

                     RWORK is DOUBLE PRECISION array, dimension (N)

           EPS3

                     EPS3 is DOUBLE PRECISION
                     A small machine-dependent value which is used to perturb
                     close eigenvalues, and to replace zero pivots.

           SMLNUM

                     SMLNUM is DOUBLE PRECISION
                     A machine-dependent value close to the underflow threshold.

           INFO

                     INFO is INTEGER
                     = 0:  successful exit
                     = 1:  inverse iteration did not converge; V is set to the
                           last iterate.

       Author
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Definition at line 147 of file zlaein.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

LAPACK                          Version 3.12.0                 SRC/zlaein.f(3)