LAPACK
3.6.1
LAPACK: Linear Algebra PACKage
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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.
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CLAEIN 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 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 The eigenvalue of H whose corresponding right or left eigenvector is to be computed. |
[in,out] | 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|. |
[out] | B | B is COMPLEX array, dimension (LDB,N) |
[in] | LDB | LDB is INTEGER The leading dimension of the array B. LDB >= max(1,N). |
[out] | RWORK | RWORK is REAL array, dimension (N) |
[in] | EPS3 | EPS3 is REAL A small machine-dependent value which is used to perturb close eigenvalues, and to replace zero pivots. |
[in] | SMLNUM | SMLNUM is REAL A machine-dependent 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 151 of file claein.f.