The FORTRAN level-1 BLAS calls for these operation are
Here
is replaced by S, D, C, or Z
to indicate the data type of the operands (single, double, complex, double precision complex).
Parameter N equals the length of the vector, n .
Parameter X equals the
address of where vector x starts in
memory. The stride for the vector is given in INCX.
The result 
is returned as the function value.