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

196 HP MLIB User’s Guide
F_SSUM/F_DSUM/F_CSUM/F_ZSUM Sum of entries of a vector
X REAL or 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.
Output R REAL scalar. The sum of the entries of vector x.