cheevd - compute all eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A
SUBROUTINE CHEEVD( JOBZ, UPLO, N, A, LDA, W, WORK, LWORK, RWORK, * LRWORK, IWORK, LIWORK, INFO) CHARACTER * 1 JOBZ, UPLO COMPLEX A(LDA,*), WORK(*) INTEGER N, LDA, LWORK, LRWORK, LIWORK, INFO INTEGER IWORK(*) REAL W(*), RWORK(*)
SUBROUTINE CHEEVD_64( JOBZ, UPLO, N, A, LDA, W, WORK, LWORK, RWORK, * LRWORK, IWORK, LIWORK, INFO) CHARACTER * 1 JOBZ, UPLO COMPLEX A(LDA,*), WORK(*) INTEGER*8 N, LDA, LWORK, LRWORK, LIWORK, INFO INTEGER*8 IWORK(*) REAL W(*), RWORK(*)
SUBROUTINE HEEVD( JOBZ, UPLO, [N], A, [LDA], W, WORK, [LWORK], * RWORK, [LRWORK], [IWORK], [LIWORK], [INFO]) CHARACTER(LEN=1) :: JOBZ, UPLO COMPLEX, DIMENSION(:) :: WORK COMPLEX, DIMENSION(:,:) :: A INTEGER :: N, LDA, LWORK, LRWORK, LIWORK, INFO INTEGER, DIMENSION(:) :: IWORK REAL, DIMENSION(:) :: W, RWORK
SUBROUTINE HEEVD_64( JOBZ, UPLO, [N], A, [LDA], W, WORK, [LWORK], * RWORK, [LRWORK], [IWORK], [LIWORK], [INFO]) CHARACTER(LEN=1) :: JOBZ, UPLO COMPLEX, DIMENSION(:) :: WORK COMPLEX, DIMENSION(:,:) :: A INTEGER(8) :: N, LDA, LWORK, LRWORK, LIWORK, INFO INTEGER(8), DIMENSION(:) :: IWORK REAL, DIMENSION(:) :: W, RWORK
#include <sunperf.h>
void cheevd(char jobz, char uplo, int n, complex *a, int lda, float *w, complex *work, int lwork, float *rwork, int lrwork, int *info);
void cheevd_64(char jobz, char uplo, long n, complex *a, long lda, float *w, complex *work, long lwork, float *rwork, long lrwork, long *info);
cheevd computes all eigenvalues and, optionally, eigenvectors of a complex Hermitian matrix A. If eigenvectors are desired, it uses a divide and conquer algorithm.
The divide and conquer algorithm makes very mild assumptions about floating point arithmetic. It will work on machines with a guard digit in add/subtract, or on those binary machines without guard digits which subtract like the Cray X-MP, Cray Y-MP, Cray C-90, or Cray-2. It could conceivably fail on hexadecimal or decimal machines without guard digits, but we know of none.
= 'N': Compute eigenvalues only;
= 'V': Compute eigenvalues and eigenvectors.
= 'U': Upper triangle of A is stored;
= 'L': Lower triangle of A is stored.
WORK(1)
returns the optimal LWORK.
If LWORK = -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 LWORK is issued by XERBLA.
RWORK(1)
returns the optimal LRWORK.
If LRWORK = -1, then a workspace query is assumed; the routine only calculates the optimal size of the RWORK array, returns this value as the first entry of the RWORK array, and no error message related to LRWORK is issued by XERBLA.
IWORK(1)
returns the optimal LIWORK.
If LIWORK = -1, then a workspace query is assumed; the routine only calculates the optimal size of the IWORK array, returns this value as the first entry of the IWORK array, and no error message related to LIWORK is issued by XERBLA.
= 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.
Based on contributions by
Jeff Rutter, Computer Science Division, University of California at Berkeley, USA