claein.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
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NAME

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.

Date:

December 2016

Definition at line 151 of file claein.f.  

Author

Generated automatically by Doxygen for LAPACK from the source code.


 

Index

NAME
SYNOPSIS
Functions/Subroutines
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)
Author
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