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

Chapter 3 Basic Matrix Operations 367
General matrix-vector multiply F_SGEMV/F_DGEMV/F_CGEMV/F_ZGEMV
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. If beta = 1 and alpha = 0, this
routine returns immediately.
Y REAL or 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 vector replaces the input.
where A can be A, A
T
, or A*.
y αAx βy+←