SDSDOT(3)       BLAS routine of NEC Numeric Library Collection       SDSDOT(3)



NAME
       SDSDOT  - BLAS level one, computes a dot product (inner product) of two
       real vectors in double precision

SYNOPSIS
       REAL FUNCTION SDSDOT ( n, sb, x, incx, y, incy )

           INTEGER          n, incx, incy

           REAL             x, y, sb


DESCRIPTION
       SDSDOT computes a dot product  of  two  real  vectors  (l   real  inner
                                                                2
       product), with the result accumulated in double precision.

       This routine performs the following vector operation:

                                                               n
              SDSDOT  <--  sb + (transpose of x) * y  =  sb + Sum  x(i)*y(i)
                                                              i=1
       where x and y are real vectors and sb is a real scalar.

       If n <= 0, SDSDOT is set to sb.

ARGUMENTS
       n       INTEGER. (input)
               Number of elements in each vector.

       sb      REAL. (input)
               Scalar to be added to inner product.

       x       REAL. (input)
               Array of dimension (n-1) * |incx| + 1.
               Array x contains the first vector operand.

       incx    INTEGER. (input)
               Increment between elements of x.
               If incx = 0, the results will be unpredictable.

       y       REAL. (input)
               Array of dimension (n-1) * |incy| + 1.
               Array y contains the second vector operand.

       incy    INTEGER. (input)
               Increment between elements of y.  If incy = 0, the results will
               be unpredictable.

RETURN VALUES
       SDSDOT  REAL. Result (dot product + SB). (output)

NOTES
       This routine is Level 1  Basic  Linear  Algebra  Subprograms  (Level  1
       BLAS).

       When  working  backward  (incx < 0 or incy < 0), each routine starts at
       the end of the vector and moves backward, as follows:

            x(1-incx * (n-1)), x(1-incx * (n-2)), ..., x(1)

            y(1-incy * (n-1)), y(1-incy * (n-2)), ..., y(1)



BLAS routine                                                         SDSDOT(3)