SUBROUTINE CHPGVD( ITYPE, JOBZ, UPLO, N, AP, BP, W, Z, LDZ, WORK, * LWORK, RWORK, LRWORK, IWORK, LIWORK, INFO) CHARACTER * 1 JOBZ, UPLO COMPLEX AP(*), BP(*), Z(LDZ,*), WORK(*) INTEGER ITYPE, N, LDZ, LWORK, LRWORK, LIWORK, INFO INTEGER IWORK(*) REAL W(*), RWORK(*) SUBROUTINE CHPGVD_64( ITYPE, JOBZ, UPLO, N, AP, BP, W, Z, LDZ, WORK, * LWORK, RWORK, LRWORK, IWORK, LIWORK, INFO) CHARACTER * 1 JOBZ, UPLO COMPLEX AP(*), BP(*), Z(LDZ,*), WORK(*) INTEGER*8 ITYPE, N, LDZ, LWORK, LRWORK, LIWORK, INFO INTEGER*8 IWORK(*) REAL W(*), RWORK(*)
SUBROUTINE HPGVD( ITYPE, JOBZ, UPLO, [N], AP, BP, W, Z, [LDZ], [WORK], * [LWORK], [RWORK], [LRWORK], [IWORK], [LIWORK], [INFO]) CHARACTER(LEN=1) :: JOBZ, UPLO COMPLEX, DIMENSION(:) :: AP, BP, WORK COMPLEX, DIMENSION(:,:) :: Z INTEGER :: ITYPE, N, LDZ, LWORK, LRWORK, LIWORK, INFO INTEGER, DIMENSION(:) :: IWORK REAL, DIMENSION(:) :: W, RWORK SUBROUTINE HPGVD_64( ITYPE, JOBZ, UPLO, [N], AP, BP, W, Z, [LDZ], * [WORK], [LWORK], [RWORK], [LRWORK], [IWORK], [LIWORK], [INFO]) CHARACTER(LEN=1) :: JOBZ, UPLO COMPLEX, DIMENSION(:) :: AP, BP, WORK COMPLEX, DIMENSION(:,:) :: Z INTEGER(8) :: ITYPE, N, LDZ, LWORK, LRWORK, LIWORK, INFO INTEGER(8), DIMENSION(:) :: IWORK REAL, DIMENSION(:) :: W, RWORK
void chpgvd(int itype, char jobz, char uplo, int n, complex *ap, complex *bp, float *w, complex *z, int ldz, int *info);
void chpgvd_64(long itype, char jobz, char uplo, long n, complex *ap, complex *bp, float *w, complex *z, long ldz, long *info);
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.
On exit, the contents of AP are destroyed.
On exit, the triangular factor U or L from the Cholesky factorization B = U**H*U or B = L*L**H, in the same storage format as B.
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 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.
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.