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

272 HP MLIB User’s Guide
SSYMV/DSYMV/CHEMV/ZHEMV Matrix-vector multiply
incx Increment for the array x, incx ≠ 0:
incx > 0 x is stored forward in array x; that is,
x
i
is stored in x((i−1)×incx+1).
incx < 0 x is stored backward in array x; that
is, x
i
is stored in x((i−n)×incx+1).
Use incx = 1 if the vector x is stored contiguously in
array x, that is, if x
i
is stored in x(i). Refer to “BLAS
Indexing Conventions” in the introduction to
Chapter 2.
beta The scalar β.
y Array of length leny = (n−1)×|incy|+1 containing the
n-vector y. Not used as input if beta = 0.