HP MLIB User's Guide Vol. 1 7th Ed.

Chapter 3 Basic Matrix Operations 349
Hermitian packed matrix-vector multiply F_CHPMV/F_ZHPMV
INTEGER*8 INCX, INCY, N, UPLO
COMPLEX*16 ALPHA, BETA
COMPLEX*16 AP( * ), X( * ), Y( * )
SUBROUTINE F_ZHPMV (UPLO, N, ALPHA, AP, X, INCX, BETA, Y,
INCY)
Input UPLO Specifies whether a triangular matrix is upper or lower
triangular. Use either BLAS_UPPER or BLAS_LOWER.
N Number of columns in matrix A, n > 0. If , the
subprograms do not reference A, X, or Y.
ALPHA The scalar ALPHA.
AP Array containing the upper or lower triangle, as
specified by uplo of an n-by-n complex Hermitian
matrix A, stored by columns in packed form.
X COMPLEX array, minimum length
(N - 1) x |incx| + 1.
INCX Increment for the array x. A vector x having component
x
i
, i = 1,..., n, is stored in an array X() with increment
argument incx. If incx > 0 then x
i
is stored in
X (1 + (i - 1) x incx). If incx < 0 then x
i
is stored in
X (1 + (N - i) x |incx|). incx = 0 is an illegal value.
BETA The scalar BETA.
Y COMPLEX array, minimum length
(N - 1) x |incy| + 1.
INCY Increment for the array y. A vector y having component
y
i
, i = 1,..., n, is stored in an array Y() with increment
argument incy. If incy > 0 then y
i
is stored in
Y(1 + (i - 1) x incy). If incy < 0 then y
i
is stored in
Y(1 + (N - i) x |incy|). incy = 0 is an illegal value.
Output Y The updated Y vector replaces the input.
n 0≤
y αAx βy with A=A
∗
+←