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

NAME
       SRC/claein.f

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

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

       Purpose:


            CLAEIN 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 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
                     The eigenvalue of H whose corresponding right or left
                     eigenvector is to be computed.

           V

                     V is COMPLEX 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 array, dimension (LDB,N)

           LDB

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

           RWORK

                     RWORK is REAL array, dimension (N)

           EPS3

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

           SMLNUM

                     SMLNUM is REAL
                     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 claein.f.

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

LAPACK                          Version 3.12.0                 SRC/claein.f(3)