!   ******************************
    subroutine addition (n,x,y,ad)
!   ******************************
!
        implicit none
!
        integer, intent(in) :: n
        real(kind=8), intent(in), dimension (n) ::x,y
        real(kind=8), intent(out) :: ad
!
        integer :: i 
!
        ad=0.d0
        do i=1,n
         ad=ad+x(i)+y(i)
        end do
!
    return
!
!   ***********************
    end subroutine addition
!   ***********************
