SUBROUTINE SSTEVD( JOBZ, N, D, E, Z, LDZ, WORK, LWORK, IWORK, * LIWORK, INFO) CHARACTER * 1 JOBZ INTEGER N, LDZ, LWORK, LIWORK, INFO INTEGER IWORK(*) REAL D(*), E(*), Z(LDZ,*), WORK(*) SUBROUTINE SSTEVD_64( JOBZ, N, D, E, Z, LDZ, WORK, LWORK, IWORK, * LIWORK, INFO) CHARACTER * 1 JOBZ INTEGER*8 N, LDZ, LWORK, LIWORK, INFO INTEGER*8 IWORK(*) REAL D(*), E(*), Z(LDZ,*), WORK(*)
SUBROUTINE STEVD( JOBZ, N, D, E, Z, [LDZ], [WORK], [LWORK], [IWORK], * [LIWORK], [INFO]) CHARACTER(LEN=1) :: JOBZ INTEGER :: N, LDZ, LWORK, LIWORK, INFO INTEGER, DIMENSION(:) :: IWORK REAL, DIMENSION(:) :: D, E, WORK REAL, DIMENSION(:,:) :: Z SUBROUTINE STEVD_64( JOBZ, N, D, E, Z, [LDZ], [WORK], [LWORK], * [IWORK], [LIWORK], [INFO]) CHARACTER(LEN=1) :: JOBZ INTEGER(8) :: N, LDZ, LWORK, LIWORK, INFO INTEGER(8), DIMENSION(:) :: IWORK REAL, DIMENSION(:) :: D, E, WORK REAL, DIMENSION(:,:) :: Z
void sstevd(char jobz, int n, float *d, float *e, float *z, int ldz, int *info);
void sstevd_64(char jobz, long n, float *d, float *e, float *z, long ldz, long *info);
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.
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.
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.