claein.f (3) - Linux Manuals
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 (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.
NOINITNOINIT is LOGICAL = .TRUE. : no initial vector supplied in V = .FALSE.: initial vector supplied in V.
NN is INTEGER The order of the matrix H. N >= 0.
HH is COMPLEX array, dimension (LDH,N) The upper Hessenberg matrix H.
LDHLDH is INTEGER The leading dimension of the array H. LDH >= max(1,N).
WW is COMPLEX The eigenvalue of H whose corresponding right or left eigenvector is to be computed.
VV 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|.
BB is COMPLEX array, dimension (LDB,N)
LDBLDB is INTEGER The leading dimension of the array B. LDB >= max(1,N).
RWORKRWORK is REAL array, dimension (N)
EPS3EPS3 is REAL A small machine-dependent value which is used to perturb close eigenvalues, and to replace zero pivots.
SMLNUMSMLNUM is REAL A machine-dependent value close to the underflow threshold.
INFOINFO 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
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