SDSDOT (n, alpha, x, incx, y, incy)
dotpr: real*4 The dot product of the two vectors x and y. If n<=0, dotpr returns the value 0.0.
n integer*4 On entry, the number of elements in the vectors x and y. On exit, n is unchanged. alpha real*4 | real*8 On entry, the scalar multiplier (alpha) for the elements of the vector x. On exit, alpha is unchanged. x real*4 | real*8 On entry, a one-dimensional array X of length at least (1+(n-1)*|incx|), containing the elements of the vector x. On exit, x is unchanged. incx integer*4 On entry, the increment for the array X. If incx >= 0, vector x is stored forward in the array, so that x(i) is stored in location X(1+(i-1)*incx). If incx < 0, vector x is stored backward in the array, so that x(i) is stored in location X(1+(n-i)*|incx|). On exit, incx is unchanged. y real*4 | real*8 On entry, a one-dimensional array Y of length at least (1+(n-1)*|incx|), containing the elements of the vector y. On exit, y is unchanged. incy integer*4 On entry, the increment for the array Y. If incy >= 0, vector y is stored forward in the array, so that y(i) is stored in location Y(1+(i-1)*incy). If incy < 0, vector y is stored backward in the array, so that y(i) is stored in location Y(1+(n-i)*|incy|). On exit, incy is unchanged.
SDSDOT scales the elements of a real vector, x, by the value of alpha and then computes the dot product of the resultant vector and another real vector, y. SDSDOT returns the result in single precision.
INTEGER*4 INCX,INCY REAL*8 X(20),Y(20),alpha REAL*4 DOTPR INCX = 1 INCY = 1 alpha = 0.4 N = 20 DOTPR = SDSDOT(N,alpha,X,INCX,Y,INCY)