LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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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. 
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.
Download ZLAEIN + dependencies [TGZ] [ZIP] [TXT]ZLAEIN uses inverse iteration to find a right or left eigenvector corresponding to the eigenvalue W of a complex upper Hessenberg matrix H.
[in]  RIGHTV  RIGHTV is LOGICAL = .TRUE. : compute right eigenvector; = .FALSE.: compute left eigenvector. 
[in]  NOINIT  NOINIT is LOGICAL = .TRUE. : no initial vector supplied in V = .FALSE.: initial vector supplied in V. 
[in]  N  N is INTEGER The order of the matrix H. N >= 0. 
[in]  H  H is COMPLEX*16 array, dimension (LDH,N) The upper Hessenberg matrix H. 
[in]  LDH  LDH is INTEGER The leading dimension of the array H. LDH >= max(1,N). 
[in]  W  W is COMPLEX*16 The eigenvalue of H whose corresponding right or left eigenvector is to be computed. 
[in,out]  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. 
[out]  B  B is COMPLEX*16 array, dimension (LDB,N) 
[in]  LDB  LDB is INTEGER The leading dimension of the array B. LDB >= max(1,N). 
[out]  RWORK  RWORK is DOUBLE PRECISION array, dimension (N) 
[in]  EPS3  EPS3 is DOUBLE PRECISION A small machinedependent value which is used to perturb close eigenvalues, and to replace zero pivots. 
[in]  SMLNUM  SMLNUM is DOUBLE PRECISION A machinedependent value close to the underflow threshold. 
[out]  INFO  INFO is INTEGER = 0: successful exit = 1: inverse iteration did not converge; V is set to the last iterate. 
Definition at line 149 of file zlaein.f.