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



NAME
       DASUM  -  BLAS level one, sums the absolute values of the elements of a
       double precision vector

SYNOPSIS
       DOUBLE PRECISION FUNCTION DASUM ( n, x, incx )

           INTEGER                       n, incx

           DOUBLE PRECISION              x


DESCRIPTION
       This routine performs the following vector operation:

                          n
               DASUM <-- Sum abs(x(i))
                         i=1

ARGUMENTS
       n       INTEGER. (input)
               Number of vector elements to be summed.

       x       DOUBLE PRECISION. (input)
               Array of dimension (n-1) * abs(incx)+ 1.
               Vector that contains elements to be summed.

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

RETURN VALUES
       DASUM   DOUBLE PRECISION. (output)
               Sum of the absolute values of the elements of the vector x.
               If n <= 0, DASUM is set to 0.

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

       When working backward (incx < 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)



BLAS routine                                                          DASUM(3)