Contents
cheev - compute all eigenvalues and, optionally, eigenvec-
tors of a complex Hermitian matrix A
SUBROUTINE CHEEV(JOBZ, UPLO, N, A, LDA, W, WORK, LDWORK, WORK2, INFO)
CHARACTER * 1 JOBZ, UPLO
COMPLEX A(LDA,*), WORK(*)
INTEGER N, LDA, LDWORK, INFO
REAL W(*), WORK2(*)
SUBROUTINE CHEEV_64(JOBZ, UPLO, N, A, LDA, W, WORK, LDWORK, WORK2,
INFO)
CHARACTER * 1 JOBZ, UPLO
COMPLEX A(LDA,*), WORK(*)
INTEGER*8 N, LDA, LDWORK, INFO
REAL W(*), WORK2(*)
F95 INTERFACE
SUBROUTINE HEEV(JOBZ, UPLO, [N], A, [LDA], W, [WORK], [LDWORK],
[WORK2], [INFO])
CHARACTER(LEN=1) :: JOBZ, UPLO
COMPLEX, DIMENSION(:) :: WORK
COMPLEX, DIMENSION(:,:) :: A
INTEGER :: N, LDA, LDWORK, INFO
REAL, DIMENSION(:) :: W, WORK2
SUBROUTINE HEEV_64(JOBZ, UPLO, [N], A, [LDA], W, [WORK], [LDWORK],
[WORK2], [INFO])
CHARACTER(LEN=1) :: JOBZ, UPLO
COMPLEX, DIMENSION(:) :: WORK
COMPLEX, DIMENSION(:,:) :: A
INTEGER(8) :: N, LDA, LDWORK, INFO
REAL, DIMENSION(:) :: W, WORK2
C INTERFACE
#include <sunperf.h>
void cheev(char jobz, char uplo, int n, complex *a, int lda,
float *w, int *info);
void cheev_64(char jobz, char uplo, long n, complex *a, long
lda, float *w, long *info);
cheev computes all eigenvalues and, optionally, eigenvectors
of a complex Hermitian matrix A.
JOBZ (input)
= 'N': Compute eigenvalues only;
= 'V': Compute eigenvalues and eigenvectors.
UPLO (input)
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored.
N (input) The order of the matrix A. N >= 0.
A (input/output)
On entry, the Hermitian matrix A. If UPLO = 'U',
the leading N-by-N upper triangular part of A con-
tains the upper triangular part of the matrix A.
If UPLO = 'L', the leading N-by-N lower triangular
part of A contains the lower triangular part of
the matrix A. On exit, if JOBZ = 'V', then if
INFO = 0, A contains the orthonormal eigenvectors
of the matrix A. If JOBZ = 'N', then on exit the
lower triangle (if UPLO='L') or the upper triangle
(if UPLO='U') of A, including the diagonal, is
destroyed.
LDA (input)
The leading dimension of the array A. LDA >=
max(1,N).
W (output)
If INFO = 0, the eigenvalues in ascending order.
WORK (workspace)
On exit, if INFO = 0, WORK(1) returns the optimal
LDWORK.
LDWORK (input)
The length of the array WORK. LDWORK >=
max(1,2*N-1). For optimal efficiency, LDWORK >=
(NB+1)*N, where NB is the blocksize for CHETRD
returned by ILAENV.
If LDWORK = -1, then a workspace query is assumed;
the routine only calculates the optimal size of
the WORK array, returns this value as the first
entry of the WORK array, and no error message
related to LDWORK is issued by XERBLA.
WORK2 (workspace)
dimension(max(1,3*N-2))
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an ille-
gal value
> 0: if INFO = i, the algorithm failed to con-
verge; i off-diagonal elements of an intermediate
tridiagonal form did not converge to zero.