bool MeshRefinement::limit_overrefined_boundary(const unsigned int max_mismatch)
{
  // This function must be run on all processors at once
  parallel_object_only();

  bool flags_changed = false;

  // Loop over all the active elements & look for mismatches to fix.
  {
    MeshBase::element_iterator       elem_it  = _mesh.active_elements_begin();
    const MeshBase::element_iterator elem_end = _mesh.active_elements_end();

    for (; elem_it != elem_end; ++elem_it)
      {
        Elem* elem = *elem_it;

        // If we don't have an interior_parent then there's nothing to
        // be mismatched with.
        if ((elem->dim() >= LIBMESH_DIM) ||
            !elem->interior_parent())
          continue;

        const unsigned char elem_level =
          cast_int<unsigned char>(elem->level() +
                                  ((elem->refinement_flag() == Elem::REFINE) ? 1 : 0));
        const unsigned char elem_p_level =
          cast_int<unsigned char>(elem->p_level() +
                                  ((elem->p_refinement_flag() == Elem::REFINE) ? 1 : 0));

        // get all relevant interior elements
        std::set<const Elem*> neighbor_set;
        elem->find_interior_neighbors(neighbor_set);

        std::set<const Elem*>::iterator n_it = neighbor_set.begin();
        for (; n_it != neighbor_set.end(); ++n_it)
          {
            // FIXME - non-const versions of the Elem set methods
            // would be nice
            Elem* neighbor = const_cast<Elem*>(*n_it);

            if (((elem_level - max_mismatch) >
                 neighbor->level()) &&
                (neighbor->refinement_flag() != Elem::REFINE))
              {
                neighbor->set_refinement_flag(Elem::REFINE);
                flags_changed = true;
              }
            if (((elem_p_level + 1 - max_mismatch) >
                 neighbor->p_level()) &&
                (neighbor->p_refinement_flag() != Elem::REFINE))
              {
                neighbor->set_p_refinement_flag(Elem::REFINE);
                flags_changed = true;
              }
          } // loop over interior neighbors
      }
  }

  return flags_changed;
}
Example #2
0
void unpack(std::vector<largest_id_type>::const_iterator in,
            Elem** out,
            MeshBase* mesh)
{
#ifndef NDEBUG
  const std::vector<largest_id_type>::const_iterator original_in = in;

  const largest_id_type incoming_header = *in++;
  libmesh_assert_equal_to (incoming_header, elem_magic_header);
#endif

  // int 0: level
  const unsigned int level =
    static_cast<unsigned int>(*in++);

#ifdef LIBMESH_ENABLE_AMR
  // int 1: p level
  const unsigned int p_level =
    static_cast<unsigned int>(*in++);

  // int 2: refinement flag
  const int rflag = *in++;
  libmesh_assert_greater_equal (rflag, 0);
  libmesh_assert_less (rflag, Elem::INVALID_REFINEMENTSTATE);
  const Elem::RefinementState refinement_flag =
    static_cast<Elem::RefinementState>(rflag);

  // int 3: p refinement flag
  const int pflag = *in++;
  libmesh_assert_greater_equal (pflag, 0);
  libmesh_assert_less (pflag, Elem::INVALID_REFINEMENTSTATE);
  const Elem::RefinementState p_refinement_flag =
    static_cast<Elem::RefinementState>(pflag);
#else
  in += 3;
#endif // LIBMESH_ENABLE_AMR

  // int 4: element type
  const int typeint = *in++;
  libmesh_assert_greater_equal (typeint, 0);
  libmesh_assert_less (typeint, INVALID_ELEM);
  const ElemType type =
    static_cast<ElemType>(typeint);

  const unsigned int n_nodes =
    Elem::type_to_n_nodes_map[type];

  // int 5: processor id
  const processor_id_type processor_id =
    static_cast<processor_id_type>(*in++);
  libmesh_assert (processor_id < mesh->n_processors() ||
                  processor_id == DofObject::invalid_processor_id);

  // int 6: subdomain id
  const subdomain_id_type subdomain_id =
    static_cast<subdomain_id_type>(*in++);

  // int 7: dof object id
  const dof_id_type id =
    static_cast<dof_id_type>(*in++);
  libmesh_assert_not_equal_to (id, DofObject::invalid_id);

#ifdef LIBMESH_ENABLE_UNIQUE_ID
  // int 8: dof object unique id
  const unique_id_type unique_id =
    static_cast<unique_id_type>(*in++);
#endif

#ifdef LIBMESH_ENABLE_AMR
  // int 9: parent dof object id
  const dof_id_type parent_id =
    static_cast<dof_id_type>(*in++);
  libmesh_assert (level == 0 || parent_id != DofObject::invalid_id);
  libmesh_assert (level != 0 || parent_id == DofObject::invalid_id);

  // int 10: local child id
  const unsigned int which_child_am_i =
    static_cast<unsigned int>(*in++);
#else
  in += 2;
#endif // LIBMESH_ENABLE_AMR

  // Make sure we don't miscount above when adding the "magic" header
  // plus the real data header
  libmesh_assert_equal_to (in - original_in, header_size + 1);

  Elem *elem = mesh->query_elem(id);

  // if we already have this element, make sure its
  // properties match, and update any missing neighbor
  // links, but then go on
  if (elem)
    {
      libmesh_assert_equal_to (elem->level(), level);
      libmesh_assert_equal_to (elem->id(), id);
//#ifdef LIBMESH_ENABLE_UNIQUE_ID
      // No check for unqiue id sanity
//#endif
      libmesh_assert_equal_to (elem->processor_id(), processor_id);
      libmesh_assert_equal_to (elem->subdomain_id(), subdomain_id);
      libmesh_assert_equal_to (elem->type(), type);
      libmesh_assert_equal_to (elem->n_nodes(), n_nodes);

#ifndef NDEBUG
      // All our nodes should be correct
      for (unsigned int i=0; i != n_nodes; ++i)
        libmesh_assert(elem->node(i) ==
                       static_cast<dof_id_type>(*in++));
#else
      in += n_nodes;
#endif

#ifdef LIBMESH_ENABLE_AMR
      libmesh_assert_equal_to (elem->p_level(), p_level);
      libmesh_assert_equal_to (elem->refinement_flag(), refinement_flag);
      libmesh_assert_equal_to (elem->p_refinement_flag(), p_refinement_flag);

      libmesh_assert (!level || elem->parent() != NULL);
      libmesh_assert (!level || elem->parent()->id() == parent_id);
      libmesh_assert (!level || elem->parent()->child(which_child_am_i) == elem);
#endif

      // Our neighbor links should be "close to" correct - we may have
      // to update them, but we can check for some inconsistencies.
      for (unsigned int n=0; n != elem->n_neighbors(); ++n)
        {
          const dof_id_type neighbor_id =
            static_cast<dof_id_type>(*in++);

	  // If the sending processor sees a domain boundary here,
	  // we'd better agree.
          if (neighbor_id == DofObject::invalid_id)
            {
              libmesh_assert (!(elem->neighbor(n)));
              continue;
            }

	  // If the sending processor has a remote_elem neighbor here,
	  // then all we know is that we'd better *not* have a domain
	  // boundary.
          if (neighbor_id == remote_elem->id())
            {
              libmesh_assert(elem->neighbor(n));
              continue;
            }

          Elem *neigh = mesh->query_elem(neighbor_id);

          // The sending processor sees a neighbor here, so if we
          // don't have that neighboring element, then we'd better
          // have a remote_elem signifying that fact.
          if (!neigh)
            {
              libmesh_assert_equal_to (elem->neighbor(n), remote_elem);
              continue;
            }

          // The sending processor has a neighbor here, and we have
          // that element, but that does *NOT* mean we're already
	  // linking to it.  Perhaps we initially received both elem
	  // and neigh from processors on which their mutual link was
	  // remote?
          libmesh_assert(elem->neighbor(n) == neigh ||
			 elem->neighbor(n) == remote_elem);

	  // If the link was originally remote, we should update it,
	  // and make sure the appropriate parts of its family link
	  // back to us.
	  if (elem->neighbor(n) == remote_elem)
            {
              elem->set_neighbor(n, neigh);

              elem->make_links_to_me_local(n);
	    }
	}

      // FIXME: We should add some debug mode tests to ensure that the
      // encoded indexing and boundary conditions are consistent.
    }
  else
    {
      // We don't already have the element, so we need to create it.

      // Find the parent if necessary
      Elem *parent = NULL;
#ifdef LIBMESH_ENABLE_AMR
      // Find a child element's parent
      if (level > 0)
        {
	  // Note that we must be very careful to construct the send
	  // connectivity so that parents are encountered before
	  // children.  If we get here and can't find the parent that
	  // is a fatal error.
          parent = mesh->elem(parent_id);
        }
      // Or assert that the sending processor sees no parent
      else
        libmesh_assert_equal_to (parent_id, static_cast<dof_id_type>(-1));
#else
      // No non-level-0 elements without AMR
      libmesh_assert_equal_to (level, 0);
#endif

      elem = Elem::build(type,parent).release();
      libmesh_assert (elem);

#ifdef LIBMESH_ENABLE_AMR
      if (level != 0)
        {
          // Since this is a newly created element, the parent must
          // have previously thought of this child as a remote element.
          libmesh_assert_equal_to (parent->child(which_child_am_i), remote_elem);

          parent->add_child(elem, which_child_am_i);
        }

      // Assign the refinement flags and levels
      elem->set_p_level(p_level);
      elem->set_refinement_flag(refinement_flag);
      elem->set_p_refinement_flag(p_refinement_flag);
      libmesh_assert_equal_to (elem->level(), level);

      // If this element definitely should have children, assign
      // remote_elem to all of them for now, for consistency.  Later
      // unpacked elements may overwrite that.
      if (!elem->active())
        for (unsigned int c=0; c != elem->n_children(); ++c)
          elem->add_child(const_cast<RemoteElem*>(remote_elem), c);

#endif // LIBMESH_ENABLE_AMR

      // Assign the IDs
      elem->subdomain_id()  = subdomain_id;
      elem->processor_id()  = processor_id;
      elem->set_id()        = id;
#ifdef LIBMESH_ENABLE_UNIQUE_ID
      elem->set_unique_id() = unique_id;
#endif

      // Assign the connectivity
      libmesh_assert_equal_to (elem->n_nodes(), n_nodes);

      for (unsigned int n=0; n != n_nodes; n++)
        elem->set_node(n) =
          mesh->node_ptr
	    (static_cast<dof_id_type>(*in++));

      for (unsigned int n=0; n<elem->n_neighbors(); n++)
        {
          const dof_id_type neighbor_id =
            static_cast<dof_id_type>(*in++);

          if (neighbor_id == DofObject::invalid_id)
	    continue;

          // We may be unpacking an element that was a ghost element on the
          // sender, in which case the element's neighbors may not all be
          // known by the packed element.  We'll have to set such
          // neighbors to remote_elem ourselves and wait for a later
          // packed element to give us better information.
          if (neighbor_id == remote_elem->id())
            {
              elem->set_neighbor(n, const_cast<RemoteElem*>(remote_elem));
	      continue;
	    }

          // If we don't have the neighbor element, then it's a
          // remote_elem until we get it.
          Elem *neigh = mesh->query_elem(neighbor_id);
          if (!neigh)
            {
              elem->set_neighbor(n, const_cast<RemoteElem*>(remote_elem));
	      continue;
	    }

          // If we have the neighbor element, then link to it, and
          // make sure the appropriate parts of its family link back
          // to us.
          elem->set_neighbor(n, neigh);

          elem->make_links_to_me_local(n);
        }

      elem->unpack_indexing(in);
    }

  in += elem->packed_indexing_size();

  // If this is a coarse element,
  // add any element side boundary condition ids
  if (level == 0)
    for (unsigned int s = 0; s != elem->n_sides(); ++s)
      {
        const int num_bcs = *in++;
        libmesh_assert_greater_equal (num_bcs, 0);

        for(int bc_it=0; bc_it < num_bcs; bc_it++)
          mesh->boundary_info->add_side (elem, s, *in++);
      }

  // Return the new element
  *out = elem;
}
//-----------------------------------------------------------------
// Mesh refinement methods
bool MeshRefinement::limit_level_mismatch_at_node (const unsigned int max_mismatch)
{
  // This function must be run on all processors at once
  parallel_only();

  bool flags_changed = false;


  // Vector holding the maximum element level that touches a node.
  std::vector<unsigned char> max_level_at_node (_mesh.n_nodes(), 0);
  std::vector<unsigned char> max_p_level_at_node (_mesh.n_nodes(), 0);


  // Loop over all the active elements & fill the vector
  {
    MeshBase::element_iterator       elem_it  = _mesh.active_elements_begin();
    const MeshBase::element_iterator elem_end = _mesh.active_elements_end();

    for (; elem_it != elem_end; ++elem_it)
      {
	const Elem* elem = *elem_it;
	const unsigned char elem_level =
	  elem->level() + ((elem->refinement_flag() == Elem::REFINE) ? 1 : 0);
	const unsigned char elem_p_level =
	  elem->p_level() + ((elem->p_refinement_flag() == Elem::REFINE) ? 1 : 0);

	// Set the max_level at each node
	for (unsigned int n=0; n<elem->n_nodes(); n++)
	  {
	    const unsigned int node_number = elem->node(n);

	    libmesh_assert_less (node_number, max_level_at_node.size());

	    max_level_at_node[node_number] =
	      std::max (max_level_at_node[node_number], elem_level);
	    max_p_level_at_node[node_number] =
	      std::max (max_p_level_at_node[node_number], elem_p_level);
	  }
      }
  }


  // Now loop over the active elements and flag the elements
  // who violate the requested level mismatch
  {
    MeshBase::element_iterator       elem_it  = _mesh.active_elements_begin();
    const MeshBase::element_iterator elem_end = _mesh.active_elements_end();

    for (; elem_it != elem_end; ++elem_it)
      {
	Elem* elem = *elem_it;
	const unsigned int elem_level = elem->level();
	const unsigned int elem_p_level = elem->p_level();

	// Skip the element if it is already fully flagged
	if (elem->refinement_flag() == Elem::REFINE &&
            elem->p_refinement_flag() == Elem::REFINE)
	  continue;

	// Loop over the nodes, check for possible mismatch
	for (unsigned int n=0; n<elem->n_nodes(); n++)
	  {
	    const unsigned int node_number = elem->node(n);

	    // Flag the element for refinement if it violates
	    // the requested level mismatch
	    if ( (elem_level + max_mismatch) < max_level_at_node[node_number]
                 && elem->refinement_flag() != Elem::REFINE)
	      {
		elem->set_refinement_flag (Elem::REFINE);
		flags_changed = true;
	      }
	    if ( (elem_p_level + max_mismatch) < max_p_level_at_node[node_number]
                 && elem->p_refinement_flag() != Elem::REFINE)
	      {
		elem->set_p_refinement_flag (Elem::REFINE);
		flags_changed = true;
	      }
	  }
      }
  }

  // If flags changed on any processor then they changed globally
  CommWorld.max(flags_changed);

  return flags_changed;
}
bool MeshRefinement::eliminate_unrefined_patches ()
{
  // This function must be run on all processors at once
  parallel_only();

  bool flags_changed = false;

  MeshBase::element_iterator       elem_it  = _mesh.active_elements_begin();
  const MeshBase::element_iterator elem_end = _mesh.active_elements_end();

  for (; elem_it != elem_end; ++elem_it)
    {
      Elem* elem = *elem_it;
      // First assume that we'll have to flag this element for both h
      // and p refinement, then change our minds if we see any
      // neighbors that are as coarse or coarser than us.
      bool h_flag_me = true,
           p_flag_me = true;


      // Skip the element if it is already fully flagged for refinement
      if (elem->p_refinement_flag() == Elem::REFINE)
	p_flag_me = false;
      if (elem->refinement_flag() == Elem::REFINE)
        {
          h_flag_me = false;
          if (!p_flag_me)
            continue;
        }
      // Test the parent if that is already flagged for coarsening
      else if (elem->refinement_flag() == Elem::COARSEN)
        {
          libmesh_assert(elem->parent());
	  elem = elem->parent();
          // FIXME - this doesn't seem right - RHS
          if (elem->refinement_flag() != Elem::COARSEN_INACTIVE)
            continue;
          p_flag_me = false;
        }

      const unsigned int my_level = elem->level();
      int my_p_adjustment = 0;
      if (elem->p_refinement_flag() == Elem::REFINE)
        my_p_adjustment = 1;
      else if (elem->p_refinement_flag() == Elem::COARSEN)
        {
          libmesh_assert_greater (elem->p_level(), 0);
          my_p_adjustment = -1;
        }
      const unsigned int my_new_p_level = elem->p_level() +
                                          my_p_adjustment;

      // Check all the element neighbors
      for (unsigned int n=0; n<elem->n_neighbors(); n++)
        {
          const Elem *neighbor = elem->neighbor(n);
	  // Quit if the element is on a local boundary
	  if (neighbor == NULL || neighbor == remote_elem)
            {
              h_flag_me = false;
              p_flag_me = false;
              break;
            }
          // if the neighbor will be equally or less refined than
	  // we are, then we will not become an unrefined island.
          // So if we are still considering h refinement:
          if (h_flag_me &&
            // If our neighbor is already at a lower level,
            // it can't end up at a higher level even if it
            // is flagged for refinement once
             ((neighbor->level() < my_level) ||
            // If our neighbor is at the same level but isn't
            // flagged for refinement, it won't end up at a
            // higher level
             ((neighbor->active()) &&
              (neighbor->refinement_flag() != Elem::REFINE)) ||
            // If our neighbor is currently more refined but is
            // a parent flagged for coarsening, it will end up
            // at the same level.
             (neighbor->refinement_flag() == Elem::COARSEN_INACTIVE)))
            {
              // We've proven we won't become an unrefined island,
              // so don't h refine to avoid that.
	      h_flag_me = false;

              // If we've also proven we don't need to p refine,
              // we don't need to check more neighbors
              if (!p_flag_me)
                break;
            }
	  if (p_flag_me)
            {
	      // if active neighbors will have a p level
	      // equal to or lower than ours, then we do not need to p
              // refine ourselves.
              if (neighbor->active())
                {
                  int p_adjustment = 0;
                  if (neighbor->p_refinement_flag() == Elem::REFINE)
                    p_adjustment = 1;
                  else if (neighbor->p_refinement_flag() == Elem::COARSEN)
                    {
                      libmesh_assert_greater (neighbor->p_level(), 0);
                      p_adjustment = -1;
                    }
                  if (my_new_p_level >= neighbor->p_level() + p_adjustment)
                    {
                      p_flag_me = false;
                      if (!h_flag_me)
                        break;
                    }
                }
              // If we have inactive neighbors, we need to
              // test all their active descendants which neighbor us
              else if (neighbor->ancestor())
                {
                  if (neighbor->min_new_p_level_by_neighbor(elem,
                      my_new_p_level + 2) <= my_new_p_level)
                    {
                      p_flag_me = false;
                      if (!h_flag_me)
                        break;
                    }
                }
            }
        }

      if (h_flag_me)
	{
	  // Parents that would create islands should no longer
          // coarsen
          if (elem->refinement_flag() == Elem::COARSEN_INACTIVE)
            {
              for (unsigned int c=0; c<elem->n_children(); c++)
                {
                  libmesh_assert_equal_to (elem->child(c)->refinement_flag(),
                                          Elem::COARSEN);
                  elem->child(c)->set_refinement_flag(Elem::DO_NOTHING);
                }
              elem->set_refinement_flag(Elem::INACTIVE);
            }
          else
	    elem->set_refinement_flag(Elem::REFINE);
	  flags_changed = true;
	}
      if (p_flag_me)
	{
          if (elem->p_refinement_flag() == Elem::COARSEN)
	    elem->set_p_refinement_flag(Elem::DO_NOTHING);
          else
	    elem->set_p_refinement_flag(Elem::REFINE);
	  flags_changed = true;
	}
    }

  // If flags changed on any processor then they changed globally
  CommWorld.max(flags_changed);

  return flags_changed;
}
//-----------------------------------------------------------------
// Mesh refinement methods
bool MeshRefinement::limit_level_mismatch_at_edge (const unsigned int max_mismatch)
{
  // This function must be run on all processors at once
  parallel_only();

  bool flags_changed = false;


  // Maps holding the maximum element level that touches an edge
  std::map<std::pair<unsigned int, unsigned int>, unsigned char>
    max_level_at_edge;
  std::map<std::pair<unsigned int, unsigned int>, unsigned char>
    max_p_level_at_edge;

  // Loop over all the active elements & fill the maps
  {
    MeshBase::element_iterator       elem_it  = _mesh.active_elements_begin();
    const MeshBase::element_iterator elem_end = _mesh.active_elements_end();

    for (; elem_it != elem_end; ++elem_it)
      {
	const Elem* elem = *elem_it;
	const unsigned char elem_level =
	  elem->level() + ((elem->refinement_flag() == Elem::REFINE) ? 1 : 0);
	const unsigned char elem_p_level =
	  elem->p_level() + ((elem->p_refinement_flag() == Elem::REFINE) ? 1 : 0);

	// Set the max_level at each edge
	for (unsigned int n=0; n<elem->n_edges(); n++)
	  {
            AutoPtr<Elem> edge = elem->build_edge(n);
            unsigned int childnode0 = edge->node(0);
            unsigned int childnode1 = edge->node(1);
            if (childnode1 < childnode0)
              std::swap(childnode0, childnode1);

	    for (const Elem *p = elem; p != NULL; p = p->parent())
	      {
                AutoPtr<Elem> pedge = p->build_edge(n);
		unsigned int node0 = pedge->node(0);
		unsigned int node1 = pedge->node(1);

                if (node1 < node0)
                  std::swap(node0, node1);

		// If elem does not share this edge with its ancestor
		// p, refinement levels of elements sharing p's edge
		// are not restricted by refinement levels of elem.
		// Furthermore, elem will not share this edge with any
		// of p's ancestors, so we can safely break out of the
		// for loop early.
		if (node0 != childnode0 && node1 != childnode1)
		  break;

                childnode0 = node0;
                childnode1 = node1;

                std::pair<unsigned int, unsigned int> edge_key =
                  std::make_pair(node0, node1);

                if (max_level_at_edge.find(edge_key) ==
                    max_level_at_edge.end())
                  {
                    max_level_at_edge[edge_key] = elem_level;
	            max_p_level_at_edge[edge_key] = elem_p_level;
                  }
                else
                  {
	            max_level_at_edge[edge_key] =
	              std::max (max_level_at_edge[edge_key], elem_level);
	            max_p_level_at_edge[edge_key] =
	              std::max (max_p_level_at_edge[edge_key], elem_p_level);
                  }
              }
	  }
      }
  }


  // Now loop over the active elements and flag the elements
  // who violate the requested level mismatch
  {
    MeshBase::element_iterator       elem_it  = _mesh.active_elements_begin();
    const MeshBase::element_iterator elem_end = _mesh.active_elements_end();

    for (; elem_it != elem_end; ++elem_it)
      {
	Elem* elem = *elem_it;
	const unsigned int elem_level = elem->level();
	const unsigned int elem_p_level = elem->p_level();

	// Skip the element if it is already fully flagged
	if (elem->refinement_flag() == Elem::REFINE &&
            elem->p_refinement_flag() == Elem::REFINE)
	  continue;

	// Loop over the nodes, check for possible mismatch
	for (unsigned int n=0; n<elem->n_edges(); n++)
	  {
            AutoPtr<Elem> edge = elem->build_edge(n);
            unsigned int node0 = edge->node(0);
            unsigned int node1 = edge->node(1);
            if (node1 < node0)
              std::swap(node0, node1);

            std::pair<unsigned int, unsigned int> edge_key =
              std::make_pair(node0, node1);

	    // Flag the element for refinement if it violates
	    // the requested level mismatch
	    if ( (elem_level + max_mismatch) < max_level_at_edge[edge_key]
                 && elem->refinement_flag() != Elem::REFINE)
	      {
		elem->set_refinement_flag (Elem::REFINE);
		flags_changed = true;
	      }
	    if ( (elem_p_level + max_mismatch) < max_p_level_at_edge[edge_key]
                 && elem->p_refinement_flag() != Elem::REFINE)
	      {
		elem->set_p_refinement_flag (Elem::REFINE);
		flags_changed = true;
	      }
	  }
      }
  }

  // If flags changed on any processor then they changed globally
  CommWorld.max(flags_changed);

  return flags_changed;
}
Example #6
0
Elem *
Packing<Elem *>::unpack (std::vector<largest_id_type>::const_iterator in,
                         MeshBase * mesh)
{
#ifndef NDEBUG
  const std::vector<largest_id_type>::const_iterator original_in = in;

  const largest_id_type incoming_header = *in++;
  libmesh_assert_equal_to (incoming_header, elem_magic_header);
#endif

  // int 0: level
  const unsigned int level =
    cast_int<unsigned int>(*in++);

#ifdef LIBMESH_ENABLE_AMR
  // int 1: p level
  const unsigned int p_level =
    cast_int<unsigned int>(*in++);

  // int 2: refinement flag and encoded has_children
  const int rflag = cast_int<int>(*in++);
  const int invalid_rflag =
    cast_int<int>(Elem::INVALID_REFINEMENTSTATE);
  libmesh_assert_greater_equal (rflag, 0);

  libmesh_assert_less (rflag, invalid_rflag*2+1);

  const bool has_children = (rflag > invalid_rflag);

  const Elem::RefinementState refinement_flag = has_children ?
    cast_int<Elem::RefinementState>(rflag - invalid_rflag - 1) :
    cast_int<Elem::RefinementState>(rflag);

  // int 3: p refinement flag
  const int pflag = cast_int<int>(*in++);
  libmesh_assert_greater_equal (pflag, 0);
  libmesh_assert_less (pflag, Elem::INVALID_REFINEMENTSTATE);
  const Elem::RefinementState p_refinement_flag =
    cast_int<Elem::RefinementState>(pflag);
#else
  in += 3;
#endif // LIBMESH_ENABLE_AMR

  // int 4: element type
  const int typeint = cast_int<int>(*in++);
  libmesh_assert_greater_equal (typeint, 0);
  libmesh_assert_less (typeint, INVALID_ELEM);
  const ElemType type =
    cast_int<ElemType>(typeint);

  const unsigned int n_nodes =
    Elem::type_to_n_nodes_map[type];

  // int 5: processor id
  const processor_id_type processor_id =
    cast_int<processor_id_type>(*in++);
  libmesh_assert (processor_id < mesh->n_processors() ||
                  processor_id == DofObject::invalid_processor_id);

  // int 6: subdomain id
  const subdomain_id_type subdomain_id =
    cast_int<subdomain_id_type>(*in++);

  // int 7: dof object id
  const dof_id_type id =
    cast_int<dof_id_type>(*in++);
  libmesh_assert_not_equal_to (id, DofObject::invalid_id);

#ifdef LIBMESH_ENABLE_UNIQUE_ID
  // int 8: dof object unique id
  const unique_id_type unique_id =
    cast_int<unique_id_type>(*in++);
#endif

#ifdef LIBMESH_ENABLE_AMR
  // int 9: parent dof object id.
  // Note: If level==0, then (*in) == invalid_id.  In
  // this case, the equality check in cast_int<unsigned>(*in) will
  // never succeed.  Therefore, we should only attempt the more
  // rigorous cast verification in cases where level != 0.
  const dof_id_type parent_id =
    (level == 0)
    ? static_cast<dof_id_type>(*in++)
    : cast_int<dof_id_type>(*in++);
  libmesh_assert (level == 0 || parent_id != DofObject::invalid_id);
  libmesh_assert (level != 0 || parent_id == DofObject::invalid_id);

  // int 10: local child id
  // Note: If level==0, then which_child_am_i is not valid, so don't
  // do the more rigorous cast verification.
  const unsigned int which_child_am_i =
    (level == 0)
    ? static_cast<unsigned int>(*in++)
    : cast_int<unsigned int>(*in++);
#else
  in += 2;
#endif // LIBMESH_ENABLE_AMR

  const dof_id_type interior_parent_id =
    static_cast<dof_id_type>(*in++);

  // Make sure we don't miscount above when adding the "magic" header
  // plus the real data header
  libmesh_assert_equal_to (in - original_in, header_size + 1);

  Elem * elem = mesh->query_elem_ptr(id);

  // if we already have this element, make sure its
  // properties match, and update any missing neighbor
  // links, but then go on
  if (elem)
    {
      libmesh_assert_equal_to (elem->level(), level);
      libmesh_assert_equal_to (elem->id(), id);
      //#ifdef LIBMESH_ENABLE_UNIQUE_ID
      // No check for unique id sanity
      //#endif
      libmesh_assert_equal_to (elem->processor_id(), processor_id);
      libmesh_assert_equal_to (elem->subdomain_id(), subdomain_id);
      libmesh_assert_equal_to (elem->type(), type);
      libmesh_assert_equal_to (elem->n_nodes(), n_nodes);

#ifndef NDEBUG
      // All our nodes should be correct
      for (unsigned int i=0; i != n_nodes; ++i)
        libmesh_assert(elem->node_id(i) ==
                       cast_int<dof_id_type>(*in++));
#else
      in += n_nodes;
#endif

#ifdef LIBMESH_ENABLE_AMR
      libmesh_assert_equal_to (elem->refinement_flag(), refinement_flag);
      libmesh_assert_equal_to (elem->has_children(), has_children);

#ifdef DEBUG
      if (elem->active())
        {
          libmesh_assert_equal_to (elem->p_level(), p_level);
          libmesh_assert_equal_to (elem->p_refinement_flag(), p_refinement_flag);
        }
#endif

      libmesh_assert (!level || elem->parent() != libmesh_nullptr);
      libmesh_assert (!level || elem->parent()->id() == parent_id);
      libmesh_assert (!level || elem->parent()->child_ptr(which_child_am_i) == elem);
#endif
      // Our interior_parent link should be "close to" correct - we
      // may have to update it, but we can check for some
      // inconsistencies.
      {
        // If the sending processor sees no interior_parent here, we'd
        // better agree.
        if (interior_parent_id == DofObject::invalid_id)
          {
            if (elem->dim() < LIBMESH_DIM)
              libmesh_assert (!(elem->interior_parent()));
          }

        // If the sending processor has a remote_elem interior_parent,
        // then all we know is that we'd better have *some*
        // interior_parent
        else if (interior_parent_id == remote_elem->id())
          {
            libmesh_assert(elem->interior_parent());
          }
        else
          {
            Elem * ip = mesh->query_elem_ptr(interior_parent_id);

            // The sending processor sees an interior parent here, so
            // if we don't have that interior element, then we'd
            // better have a remote_elem signifying that fact.
            if (!ip)
              libmesh_assert_equal_to (elem->interior_parent(), remote_elem);
            else
              {
                // The sending processor has an interior_parent here,
                // and we have that element, but that does *NOT* mean
                // we're already linking to it.  Perhaps we initially
                // received elem from a processor on which the
                // interior_parent link was remote?
                libmesh_assert(elem->interior_parent() == ip ||
                               elem->interior_parent() == remote_elem);

                // If the link was originally remote, update it
                if (elem->interior_parent() == remote_elem)
                  {
                    elem->set_interior_parent(ip);
                  }
              }
          }
      }

      // Our neighbor links should be "close to" correct - we may have
      // to update a remote_elem link, and we can check for possible
      // inconsistencies along the way.
      //
      // For subactive elements, we don't bother keeping neighbor
      // links in good shape, so there's nothing we need to set or can
      // safely assert here.
      if (!elem->subactive())
        for (auto n : elem->side_index_range())
          {
            const dof_id_type neighbor_id =
              cast_int<dof_id_type>(*in++);

            // If the sending processor sees a domain boundary here,
            // we'd better agree.
            if (neighbor_id == DofObject::invalid_id)
              {
                libmesh_assert (!(elem->neighbor_ptr(n)));
                continue;
              }

            // If the sending processor has a remote_elem neighbor here,
            // then all we know is that we'd better *not* have a domain
            // boundary.
            if (neighbor_id == remote_elem->id())
              {
                libmesh_assert(elem->neighbor_ptr(n));
                continue;
              }

            Elem * neigh = mesh->query_elem_ptr(neighbor_id);

            // The sending processor sees a neighbor here, so if we
            // don't have that neighboring element, then we'd better
            // have a remote_elem signifying that fact.
            if (!neigh)
              {
                libmesh_assert_equal_to (elem->neighbor_ptr(n), remote_elem);
                continue;
              }

            // The sending processor has a neighbor here, and we have
            // that element, but that does *NOT* mean we're already
            // linking to it.  Perhaps we initially received both elem
            // and neigh from processors on which their mutual link was
            // remote?
            libmesh_assert(elem->neighbor_ptr(n) == neigh ||
                           elem->neighbor_ptr(n) == remote_elem);

            // If the link was originally remote, we should update it,
            // and make sure the appropriate parts of its family link
            // back to us.
            if (elem->neighbor_ptr(n) == remote_elem)
              {
                elem->set_neighbor(n, neigh);

                elem->make_links_to_me_local(n);
              }
          }

      // Our p level and refinement flags should be "close to" correct
      // if we're not an active element - we might have a p level
      // increased or decreased by changes in remote_elem children.
      //
      // But if we have remote_elem children, then we shouldn't be
      // doing a projection on this inactive element on this
      // processor, so we won't need correct p settings.  Couldn't
      // hurt to update, though.
#ifdef LIBMESH_ENABLE_AMR
      if (elem->processor_id() != mesh->processor_id())
        {
          elem->hack_p_level(p_level);
          elem->set_p_refinement_flag(p_refinement_flag);
        }
#endif // LIBMESH_ENABLE_AMR

      // FIXME: We should add some debug mode tests to ensure that the
      // encoded indexing and boundary conditions are consistent.
    }
  else
    {
      // We don't already have the element, so we need to create it.

      // Find the parent if necessary
      Elem * parent = libmesh_nullptr;
#ifdef LIBMESH_ENABLE_AMR
      // Find a child element's parent
      if (level > 0)
        {
          // Note that we must be very careful to construct the send
          // connectivity so that parents are encountered before
          // children.  If we get here and can't find the parent that
          // is a fatal error.
          parent = mesh->elem_ptr(parent_id);
        }
      // Or assert that the sending processor sees no parent
      else
        libmesh_assert_equal_to (parent_id, DofObject::invalid_id);
#else
      // No non-level-0 elements without AMR
      libmesh_assert_equal_to (level, 0);
#endif

      elem = Elem::build(type,parent).release();
      libmesh_assert (elem);

#ifdef LIBMESH_ENABLE_AMR
      if (level != 0)
        {
          // Since this is a newly created element, the parent must
          // have previously thought of this child as a remote element.
          libmesh_assert_equal_to (parent->child_ptr(which_child_am_i), remote_elem);

          parent->add_child(elem, which_child_am_i);
        }

      // Assign the refinement flags and levels
      elem->set_p_level(p_level);
      elem->set_refinement_flag(refinement_flag);
      elem->set_p_refinement_flag(p_refinement_flag);
      libmesh_assert_equal_to (elem->level(), level);

      // If this element should have children, assign remote_elem to
      // all of them for now, for consistency.  Later unpacked
      // elements may overwrite that.
      if (has_children)
        {
          const unsigned int nc = elem->n_children();
          for (unsigned int c=0; c != nc; ++c)
            elem->add_child(const_cast<RemoteElem *>(remote_elem), c);
        }

#endif // LIBMESH_ENABLE_AMR

      // Assign the IDs
      elem->subdomain_id()  = subdomain_id;
      elem->processor_id()  = processor_id;
      elem->set_id()        = id;
#ifdef LIBMESH_ENABLE_UNIQUE_ID
      elem->set_unique_id() = unique_id;
#endif

      // Assign the connectivity
      libmesh_assert_equal_to (elem->n_nodes(), n_nodes);

      for (unsigned int n=0; n != n_nodes; n++)
        elem->set_node(n) =
          mesh->node_ptr
          (cast_int<dof_id_type>(*in++));

      // Set interior_parent if found
      {
        // We may be unpacking an element that was a ghost element on the
        // sender, in which case the element's interior_parent may not be
        // known by the packed element.  We'll have to set such
        // interior_parents to remote_elem ourselves and wait for a
        // later packed element to give us better information.
        if (interior_parent_id == remote_elem->id())
          {
            elem->set_interior_parent
              (const_cast<RemoteElem *>(remote_elem));
          }
        else if (interior_parent_id != DofObject::invalid_id)
          {
            // If we don't have the interior parent element, then it's
            // a remote_elem until we get it.
            Elem * ip = mesh->query_elem_ptr(interior_parent_id);
            if (!ip )
              elem->set_interior_parent
                (const_cast<RemoteElem *>(remote_elem));
            else
              elem->set_interior_parent(ip);
          }
      }

      for (auto n : elem->side_index_range())
        {
          const dof_id_type neighbor_id =
            cast_int<dof_id_type>(*in++);

          if (neighbor_id == DofObject::invalid_id)
            continue;

          // We may be unpacking an element that was a ghost element on the
          // sender, in which case the element's neighbors may not all be
          // known by the packed element.  We'll have to set such
          // neighbors to remote_elem ourselves and wait for a later
          // packed element to give us better information.
          if (neighbor_id == remote_elem->id())
            {
              elem->set_neighbor(n, const_cast<RemoteElem *>(remote_elem));
              continue;
            }

          // If we don't have the neighbor element, then it's a
          // remote_elem until we get it.
          Elem * neigh = mesh->query_elem_ptr(neighbor_id);
          if (!neigh)
            {
              elem->set_neighbor(n, const_cast<RemoteElem *>(remote_elem));
              continue;
            }

          // If we have the neighbor element, then link to it, and
          // make sure the appropriate parts of its family link back
          // to us.
          elem->set_neighbor(n, neigh);

          elem->make_links_to_me_local(n);
        }

      elem->unpack_indexing(in);
    }

  in += elem->packed_indexing_size();

  // If this is a coarse element,
  // add any element side or edge boundary condition ids
  if (level == 0)
    {
      for (auto s : elem->side_index_range())
        {
          const boundary_id_type num_bcs =
            cast_int<boundary_id_type>(*in++);

          for (boundary_id_type bc_it=0; bc_it < num_bcs; bc_it++)
            mesh->get_boundary_info().add_side
              (elem, s, cast_int<boundary_id_type>(*in++));
        }

      for (auto e : elem->edge_index_range())
        {
          const boundary_id_type num_bcs =
            cast_int<boundary_id_type>(*in++);

          for (boundary_id_type bc_it=0; bc_it < num_bcs; bc_it++)
            mesh->get_boundary_info().add_edge
              (elem, e, cast_int<boundary_id_type>(*in++));
        }

      for (unsigned short sf=0; sf != 2; ++sf)
        {
          const boundary_id_type num_bcs =
            cast_int<boundary_id_type>(*in++);

          for (boundary_id_type bc_it=0; bc_it < num_bcs; bc_it++)
            mesh->get_boundary_info().add_shellface
              (elem, sf, cast_int<boundary_id_type>(*in++));
        }
    }

  // Return the new element
  return elem;
}
//-----------------------------------------------------------------
// Mesh refinement methods
bool MeshRefinement::limit_level_mismatch_at_node (const unsigned int max_mismatch)
{
  // This function must be run on all processors at once
  parallel_object_only();

  bool flags_changed = false;


  // Vector holding the maximum element level that touches a node.
  std::vector<unsigned char> max_level_at_node (_mesh.n_nodes(), 0);
  std::vector<unsigned char> max_p_level_at_node (_mesh.n_nodes(), 0);

  // Loop over all the active elements & fill the vector
  {
    MeshBase::element_iterator       elem_it  = _mesh.active_elements_begin();
    const MeshBase::element_iterator elem_end = _mesh.active_elements_end();

    for (; elem_it != elem_end; ++elem_it)
      {
        const Elem* elem = *elem_it;
        const unsigned char elem_level =
          cast_int<unsigned char>(elem->level() +
                                  ((elem->refinement_flag() == Elem::REFINE) ? 1 : 0));
        const unsigned char elem_p_level =
          cast_int<unsigned char>(elem->p_level() +
                                  ((elem->p_refinement_flag() == Elem::REFINE) ? 1 : 0));

        // Set the max_level at each node
        for (unsigned int n=0; n<elem->n_nodes(); n++)
          {
            const dof_id_type node_number = elem->node(n);

            libmesh_assert_less (node_number, max_level_at_node.size());

            max_level_at_node[node_number] =
              std::max (max_level_at_node[node_number], elem_level);
            max_p_level_at_node[node_number] =
              std::max (max_p_level_at_node[node_number], elem_p_level);
          }
      }
  }


  // Now loop over the active elements and flag the elements
  // who violate the requested level mismatch. Alternatively, if
  // _enforce_mismatch_limit_prior_to_refinement is true, swap refinement flags
  // accordingly.
  {
    MeshBase::element_iterator       elem_it  = _mesh.active_elements_begin();
    const MeshBase::element_iterator elem_end = _mesh.active_elements_end();

    for (; elem_it != elem_end; ++elem_it)
      {
        Elem* elem = *elem_it;
        const unsigned int elem_level = elem->level();
        const unsigned int elem_p_level = elem->p_level();

        // Skip the element if it is already fully flagged
        // unless we are enforcing mismatch prior to refienemnt and may need to
        // remove the refinement flag(s)
        if (elem->refinement_flag() == Elem::REFINE &&
            elem->p_refinement_flag() == Elem::REFINE
            && !_enforce_mismatch_limit_prior_to_refinement)
          continue;

        // Loop over the nodes, check for possible mismatch
        for (unsigned int n=0; n<elem->n_nodes(); n++)
          {
            const dof_id_type node_number = elem->node(n);

            // Flag the element for refinement if it violates
            // the requested level mismatch
            if ((elem_level + max_mismatch) < max_level_at_node[node_number]
                && elem->refinement_flag() != Elem::REFINE)
              {
                elem->set_refinement_flag (Elem::REFINE);
                flags_changed = true;
              }
            if ((elem_p_level + max_mismatch) < max_p_level_at_node[node_number]
                && elem->p_refinement_flag() != Elem::REFINE)
              {
                elem->set_p_refinement_flag (Elem::REFINE);
                flags_changed = true;
              }

            // Possibly enforce limit mismatch prior to refinement
            flags_changed |= this->enforce_mismatch_limit_prior_to_refinement(elem, POINT, max_mismatch);
          }
      }
  }

  // If flags changed on any processor then they changed globally
  this->comm().max(flags_changed);

  return flags_changed;
}