ztrevc
ztrevc - compute some or all of the right and/or left eigenvectors of a complex upper triangular matrix T
SUBROUTINE ZTREVC( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL, VR,
* LDVR, MM, M, WORK, RWORK, INFO)
CHARACTER * 1 SIDE, HOWMNY
DOUBLE COMPLEX T(LDT,*), VL(LDVL,*), VR(LDVR,*), WORK(*)
INTEGER N, LDT, LDVL, LDVR, MM, M, INFO
LOGICAL SELECT(*)
DOUBLE PRECISION RWORK(*)
SUBROUTINE ZTREVC_64( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL, VR,
* LDVR, MM, M, WORK, RWORK, INFO)
CHARACTER * 1 SIDE, HOWMNY
DOUBLE COMPLEX T(LDT,*), VL(LDVL,*), VR(LDVR,*), WORK(*)
INTEGER*8 N, LDT, LDVL, LDVR, MM, M, INFO
LOGICAL*8 SELECT(*)
DOUBLE PRECISION RWORK(*)
SUBROUTINE TREVC( SIDE, HOWMNY, SELECT, [N], T, [LDT], VL, [LDVL],
* VR, [LDVR], MM, M, [WORK], [RWORK], [INFO])
CHARACTER(LEN=1) :: SIDE, HOWMNY
COMPLEX(8), DIMENSION(:) :: WORK
COMPLEX(8), DIMENSION(:,:) :: T, VL, VR
INTEGER :: N, LDT, LDVL, LDVR, MM, M, INFO
LOGICAL, DIMENSION(:) :: SELECT
REAL(8), DIMENSION(:) :: RWORK
SUBROUTINE TREVC_64( SIDE, HOWMNY, SELECT, [N], T, [LDT], VL, [LDVL],
* VR, [LDVR], MM, M, [WORK], [RWORK], [INFO])
CHARACTER(LEN=1) :: SIDE, HOWMNY
COMPLEX(8), DIMENSION(:) :: WORK
COMPLEX(8), DIMENSION(:,:) :: T, VL, VR
INTEGER(8) :: N, LDT, LDVL, LDVR, MM, M, INFO
LOGICAL(8), DIMENSION(:) :: SELECT
REAL(8), DIMENSION(:) :: RWORK
#include <sunperf.h>
void ztrevc(char side, char howmny, logical *select, int n, doublecomplex *t, int ldt, doublecomplex *vl, int ldvl, doublecomplex *vr, int ldvr, int mm, int *m, int *info);
void ztrevc_64(char side, char howmny, logical *select, long n, doublecomplex *t, long ldt, doublecomplex *vl, long ldvl, doublecomplex *vr, long ldvr, long mm, long *m, long *info);
ztrevc computes some or all of the right and/or left eigenvectors of
a complex upper triangular matrix T.
The right eigenvector x and the left eigenvector y of T corresponding
to an eigenvalue w are defined by:
T*x = w*x, y'*T = w*y'
where y' denotes the conjugate transpose of the vector y.
If all eigenvectors are requested, the routine may either return the
matrices X and/or Y of right or left eigenvectors of T, or the
products Q*X and/or Q*Y, where Q is an input unitary
matrix. If T was obtained from the Schur factorization of an
original matrix A = Q*T*Q', then Q*X and Q*Y are the matrices of
right or left eigenvectors of A.
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* SIDE (input)
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* HOWMNY (input)
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* SELECT (input/output)
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If HOWMNY = 'S', SELECT specifies the eigenvectors to be
computed.
If HOWMNY = 'A' or 'B', SELECT is not referenced.
To select the eigenvector corresponding to the j-th
eigenvalue, SELECT(j) must be set to .TRUE..
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* N (input)
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The order of the matrix T. N >= 0.
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* T (input/output)
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The upper triangular matrix T. T is modified, but restored
on exit.
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* LDT (input)
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The leading dimension of the array T. LDT >= max(1,N).
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* VL (input/output)
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On entry, if SIDE = 'L' or 'B' and HOWMNY = 'B', VL must
contain an N-by-N matrix Q (usually the unitary matrix Q of
Schur vectors returned by CHSEQR).
On exit, if SIDE = 'L' or 'B', VL contains:
if HOWMNY = 'A', the matrix Y of left eigenvectors of T;
VL is lower triangular. The i-th column
VL(i) of VL is the eigenvector corresponding
to T(i,i).
if HOWMNY = 'B', the matrix Q*Y;
if HOWMNY = 'S', the left eigenvectors of T specified by
SELECT, 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 SIDE = 'R' or 'B' and HOWMNY = 'B', VR must
contain an N-by-N matrix Q (usually the unitary matrix Q of
Schur vectors returned by CHSEQR).
On exit, if SIDE = 'R' or 'B', VR contains:
if HOWMNY = 'A', the matrix X of right eigenvectors of T;
VR is upper triangular. The i-th column
VR(i) of VR is the eigenvector corresponding
to T(i,i).
if HOWMNY = 'B', the matrix Q*X;
if HOWMNY = 'S', the right eigenvectors of T specified by
SELECT, 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 actually
used to store the eigenvectors. If HOWMNY = 'A' or 'B', M
is set to N. Each selected eigenvector occupies one
column.
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* WORK (workspace)
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dimension(2*N)
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* RWORK (workspace)
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dimension(N)
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* INFO (output)
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