claein.f man page

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 (logicalRIGHTV, logicalNOINIT, integerN, complex, dimension( ldh, * )H, integerLDH, complexW, complex, dimension( * )V, complex, dimension( ldb, * )B, integerLDB, real, dimension( * )RWORK, realEPS3, realSMLNUM, integerINFO)

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.

Date:

September 2012

Definition at line 149 of file claein.f.

Author

Generated automatically by Doxygen for LAPACK from the source code.

Referenced By

claein(3) is an alias of claein.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK