cheev(3P) Sun Performance Library cheev(3P)NAMEcheev - compute all eigenvalues and, optionally, eigenvectors of a com‐
plex Hermitian matrix A
SYNOPSIS
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);
PURPOSEcheev computes all eigenvalues and, optionally, eigenvectors of a com‐
plex Hermitian matrix A.
ARGUMENTS
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 contains the upper triangu‐
lar 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 diago‐
nal, 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 rou‐
tine 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 illegal value
> 0: if INFO = i, the algorithm failed to converge; i off-
diagonal elements of an intermediate tridiagonal form did not
converge to zero.
6 Mar 2009 cheev(3P)
