zhpgst(3P) Sun Performance Library zhpgst(3P)NAMEzhpgst - reduce a complex Hermitian-definite generalized eigenproblem
to standard form, using packed storage
SYNOPSIS
SUBROUTINE ZHPGST(ITYPE, UPLO, N, AP, BP, INFO)
CHARACTER * 1 UPLO
DOUBLE COMPLEX AP(*), BP(*)
INTEGER ITYPE, N, INFO
SUBROUTINE ZHPGST_64(ITYPE, UPLO, N, AP, BP, INFO)
CHARACTER * 1 UPLO
DOUBLE COMPLEX AP(*), BP(*)
INTEGER*8 ITYPE, N, INFO
F95 INTERFACE
SUBROUTINE HPGST(ITYPE, UPLO, [N], AP, BP, [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX(8), DIMENSION(:) :: AP, BP
INTEGER :: ITYPE, N, INFO
SUBROUTINE HPGST_64(ITYPE, UPLO, [N], AP, BP, [INFO])
CHARACTER(LEN=1) :: UPLO
COMPLEX(8), DIMENSION(:) :: AP, BP
INTEGER(8) :: ITYPE, N, INFO
C INTERFACE
#include <sunperf.h>
void zhpgst(int itype, char uplo, int n, doublecomplex *ap, doublecom‐
plex *bp, int *info);
void zhpgst_64(long itype, char uplo, long n, doublecomplex *ap, dou‐
blecomplex *bp, long *info);
PURPOSEzhpgst reduces a complex Hermitian-definite generalized eigenproblem to
standard form, using packed storage.
If ITYPE = 1, the problem is A*x = lambda*B*x,
and A is overwritten by inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H)
If ITYPE = 2 or 3, the problem is A*B*x = lambda*x or
B*A*x = lambda*x, and A is overwritten by U*A*U**H or L**H*A*L.
B must have been previously factorized as U**H*U or L*L**H by CPPTRF.
ARGUMENTS
ITYPE (input)
= 1: compute inv(U**H)*A*inv(U) or inv(L)*A*inv(L**H);
= 2 or 3: compute U*A*U**H or L**H*A*L.
UPLO (input)
= 'U': Upper triangle of A is stored and B is factored as
U**H*U; = 'L': Lower triangle of A is stored and B is fac‐
tored as L*L**H.
N (input) The order of the matrices A and B. N >= 0.
AP (input/output) COMPLEX*16 array, dimension (N*(N+1)/2)
On entry, the upper or lower triangle of the Hermitian matrix
A, packed columnwise in a linear array. The j-th column of A
is stored in the array AP as follows: if UPLO = 'U', AP(i +
(j-1)*j/2) = A(i,j) for 1<=i<=j; if UPLO = 'L', AP(i +
(j-1)*(2n-j)/2) = A(i,j) for j<=i<=n.
On exit, if INFO = 0, the transformed matrix, stored in the
same format as A.
BP (input) COMPLEX*16 array, dimension (N*(N+1)/2)
The triangular factor from the Cholesky factorization of B,
stored in the same format as A, as returned by CPPTRF.
INFO (output)
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value
6 Mar 2009 zhpgst(3P)
