SDOT or DDOT Function

Base Operating System and Extensions Technical Reference, Volume 2

Returns the dot product of two vectors.

BLAS Library (libblas.a)

REAL FUNCTION SDOT(N, X, INCX, Y, INCY)
INTEGER INCX, INCY, N
REAL X(*), Y(*)

DOUBLE PRECISION FUNCTION DDOT(N, X, INCX, Y, INCY)
INTEGER INCX, INCY, N
DOUBLE PRECISION X(*), Y(*)

The SDOT or DDOT function returns the dot product of vectors X and Y.

N	On entry, N specifies the number of elements in X and Y; unchanged on exit.
X	Vector of dimension at least (1 + (N-1) * abs(INCX) ); unchanged on exit.
INCX	On entry, INCX specifies the increment for the elements of X; unchanged on exit.
Y	Vector of dimension at least (1 + (N-1) * abs(INCY) ); unchanged on exit.
INCY	On entry, INCY specifies the increment for the elements of Y; unchanged on exit.

For values of N <= 0, a value of 0 is returned.