zlaein.f man page

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.

Date:

December 2016

Definition at line 151 of file zlaein.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

The man page zlaein(3) is an alias of zlaein.f(3).

Sat Jun 24 2017 Version 3.7.1 LAPACK