tree_graph__register_node Subroutine

   pure subroutine tree_graph__register_node(self, node)
      implicit none
      class(tree_t), intent(inout) :: self
      type(tree_node_t), intent(inout) :: node

      integer :: top

      top = self%top + 1
      if (top > ubound(self%nodes, dim=1)) then
         call self%reallocate()
      end if
      node%own_i = top

      self%nodes(top) = node
      self%nodes(top)%is_registered = .true.
      self%top = top

   end subroutine tree_graph__register_node