chsein
chsein - use inverse iteration to find specified right and/or left eigenvectors of a complex upper Hessenberg matrix H
SUBROUTINE CHSEIN( SIDE, EIGSRC, INITV, SELECT, N, H, LDH, W, VL,
* LDVL, VR, LDVR, MM, M, WORK, RWORK, IFAILL, IFAILR, INFO)
CHARACTER * 1 SIDE, EIGSRC, INITV
COMPLEX H(LDH,*), W(*), VL(LDVL,*), VR(LDVR,*), WORK(*)
INTEGER N, LDH, LDVL, LDVR, MM, M, INFO
INTEGER IFAILL(*), IFAILR(*)
LOGICAL SELECT(*)
REAL RWORK(*)
SUBROUTINE CHSEIN_64( SIDE, EIGSRC, INITV, SELECT, N, H, LDH, W, VL,
* LDVL, VR, LDVR, MM, M, WORK, RWORK, IFAILL, IFAILR, INFO)
CHARACTER * 1 SIDE, EIGSRC, INITV
COMPLEX H(LDH,*), W(*), VL(LDVL,*), VR(LDVR,*), WORK(*)
INTEGER*8 N, LDH, LDVL, LDVR, MM, M, INFO
INTEGER*8 IFAILL(*), IFAILR(*)
LOGICAL*8 SELECT(*)
REAL RWORK(*)
SUBROUTINE HSEIN( SIDE, EIGSRC, INITV, SELECT, [N], H, [LDH], W, VL,
* [LDVL], VR, [LDVR], MM, M, [WORK], [RWORK], IFAILL, IFAILR, [INFO])
CHARACTER(LEN=1) :: SIDE, EIGSRC, INITV
COMPLEX, DIMENSION(:) :: W, WORK
COMPLEX, DIMENSION(:,:) :: H, VL, VR
INTEGER :: N, LDH, LDVL, LDVR, MM, M, INFO
INTEGER, DIMENSION(:) :: IFAILL, IFAILR
LOGICAL, DIMENSION(:) :: SELECT
REAL, DIMENSION(:) :: RWORK
SUBROUTINE HSEIN_64( SIDE, EIGSRC, INITV, SELECT, [N], H, [LDH], W,
* VL, [LDVL], VR, [LDVR], MM, M, [WORK], [RWORK], IFAILL, IFAILR,
* [INFO])
CHARACTER(LEN=1) :: SIDE, EIGSRC, INITV
COMPLEX, DIMENSION(:) :: W, WORK
COMPLEX, DIMENSION(:,:) :: H, VL, VR
INTEGER(8) :: N, LDH, LDVL, LDVR, MM, M, INFO
INTEGER(8), DIMENSION(:) :: IFAILL, IFAILR
LOGICAL(8), DIMENSION(:) :: SELECT
REAL, DIMENSION(:) :: RWORK
#include <sunperf.h>
void chsein(char side, char eigsrc, char initv, logical *select, int n, complex *h, int ldh, complex *w, complex *vl, int ldvl, complex *vr, int ldvr, int mm, int *m, int *ifaill, int *ifailr, int *info);
void chsein_64(char side, char eigsrc, char initv, logical *select, long n, complex *h, long ldh, complex *w, complex *vl, long ldvl, complex *vr, long ldvr, long mm, long *m, long *ifaill, long *ifailr, long *info);
chsein uses inverse iteration to find specified right and/or left
eigenvectors of a complex upper Hessenberg matrix H.
The right eigenvector x and the left eigenvector y of the matrix H
corresponding to an eigenvalue w are defined by:
H * x = w * x, y**h * H = w * y**h
where y**h denotes the conjugate transpose of the vector y.
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* SIDE (input)
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* EIGSRC (input)
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Specifies the source of eigenvalues supplied in W:
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* INITV (input)
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* SELECT (input)
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Specifies the eigenvectors to be computed. To select the
eigenvector corresponding to the eigenvalue W(j),
SELECT(j) must be set to .TRUE..
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* N (input)
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The order of the matrix H. N >= 0.
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* H (input)
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The upper Hessenberg matrix H.
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* LDH (input)
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The leading dimension of the array H. LDH >= max(1,N).
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* W (input/output)
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On entry, the eigenvalues of H.
On exit, the real parts of W may have been altered since
close eigenvalues are perturbed slightly in searching for
independent eigenvectors.
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* VL (input/output)
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On entry, if INITV = 'U' and SIDE = 'L' or 'B', VL must
contain starting vectors for the inverse iteration for the
left eigenvectors; the starting vector for each eigenvector
must be in the same column in which the eigenvector will be
stored.
On exit, if SIDE = 'L' or 'B', the left eigenvectors
specified by SELECT will be stored consecutively in the
columns of VL, in the same order as their eigenvalues.
If SIDE = 'R', VL is not referenced.
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* LDVL (input)
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The leading dimension of the array VL.
LDVL >= max(1,N) if SIDE = 'L' or 'B'; LDVL >= 1 otherwise.
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* VR (input/output)
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On entry, if INITV = 'U' and SIDE = 'R' or 'B', VR must
contain starting vectors for the inverse iteration for the
right eigenvectors; the starting vector for each eigenvector
must be in the same column in which the eigenvector will be
stored.
On exit, if SIDE = 'R' or 'B', the right eigenvectors
specified by SELECT will be stored consecutively in the
columns of VR, in the same order as their eigenvalues.
If SIDE = 'L', VR is not referenced.
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* LDVR (input)
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The leading dimension of the array VR.
LDVR >= max(1,N) if SIDE = 'R' or 'B'; LDVR >= 1 otherwise.
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* MM (input)
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The number of columns in the arrays VL and/or VR. MM >= M.
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* M (output)
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The number of columns in the arrays VL and/or VR required to
store the eigenvectors (= the number of .TRUE. elements in
SELECT).
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* WORK (workspace)
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dimension(N*N)
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* RWORK (workspace)
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dimension(N)
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* IFAILL (output)
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If SIDE = 'L' or 'B', IFAILL(i) = j > 0 if the left
eigenvector in the i-th column of VL (corresponding to the
eigenvalue w(j)) failed to converge; IFAILL(i) = 0 if the
eigenvector converged satisfactorily.
If SIDE = 'R', IFAILL is not referenced.
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* IFAILR (output)
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If SIDE = 'R' or 'B', IFAILR(i) = j > 0 if the right
eigenvector in the i-th column of VR (corresponding to the
eigenvalue w(j)) failed to converge; IFAILR(i) = 0 if the
eigenvector converged satisfactorily.
If SIDE = 'L', IFAILR is not referenced.
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* INFO (output)
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