set_direction Module Subroutine

  module subroutine set_direction(this, direction)
    !! Set the direction for the array (for higher-order derivatives)
    implicit none
    class(array_type), intent(inout) :: this
    real(real32), dimension(:), intent(in) :: direction

    if(allocated(this%direction)) deallocate(this%direction)
    if(size(this%val,1).ne.size(direction))then
       call stop_program('Direction size does not match array size in set_direction')
    end if
    this%direction = direction

  end subroutine set_direction