DAXPY(3)                    MathKeisan BLAS routine                   DAXPY(3)



NAME
       DAXPY - BLAS level one axpy subroutine

SYNOPSIS
       SUBROUTINE DAXPY    ( n, alpha, x, incx, y, incy )

           INTEGER           n, incx, incy

           DOUBLE PRECISION  alpha, x, y


DESCRIPTION
       DAXPY  adds  a  scalar multiple of a double precision vector to another
       double precision vector.

       DAXPY computes a constant alpha times a vector x plus a vector y.   The
       result overwrites the initial values of vector y.

       This routine performs the following vector operation:

            y  <--  alpha*x + y

       incx and incy specify the increment between two consecutive
       elements of respectively vector x and y.

ARGUMENTS
       n       INTEGER. (input)
               Number  of  elements in the vectors.  If n <= 0, these routines
               return without any computation.

       alpha   DOUBLE PRECISION. (input)
               If alpha = 0 this routine returns without any computation.

       x       DOUBLE PRECISION, (input)
               Array of dimension (n-1) * |incx| + 1.  Contains the vector  to
               be scaled before summation.

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

       y       DOUBLE PRECISION, (input and output)
               array of dimension (n-1) * |incy| + 1.
               Before calling the routine, y contains the vector to be summed.
               After the routine ends, y contains the result of the summation.

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

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)

RETURN VALUES
       When  n <= 0, double precision alpha = 0., this routine returns immedi-
       ately with no change in its arguments.



MathKeisan                                                            DAXPY(3)