--- /dev/null
+Deprecated: The GridReordering class as well as
+Triangulation::create_triangulation_compatibility have been deprecated.
+These functions use the old-style (before 5.2) numbering and have been
+unofficially deprecated since 2005.
+<br>
+(David Wells, 2021/04/22)
DEAL_II_NAMESPACE_OPEN
-/**
- * An exception that is thrown whenever the edges of a mesh are not
- * orientable.
- */
-DeclExceptionMsg(ExcMeshNotOrientable,
- "The edges of the mesh are not consistently orientable.");
-
-
/**
* A class implementing various grid reordering algorithms. For more information
* see the @ref reordering "reordering module".
+ *
+ * @deprecated Use GridTools::invert_all_negative_measure_cells() or
+ * GridTools::consistently_order_cells() instead of the functions provided by
+ * this class. Usage of the old-style numbering is deprecated.
*/
template <int dim, int spacedim = dim>
-class GridReordering
+class DEAL_II_DEPRECATED_EARLY GridReordering
{
public:
/**
* vertices within a cell. If false (the default), then use the "old-style"
* ordering of vertices within cells used by deal.II before version 5.2 and
* as explained in the documentation of this class.
+ *
+ * @deprecated Use GridTools::consistently_order_cells() instead.
*/
+ DEAL_II_DEPRECATED_EARLY
static void
reorder_cells(std::vector<CellData<dim>> &original_cells,
const bool use_new_style_ordering = false);
const std::vector<Point<spacedim>> &all_vertices,
std::vector<CellData<dim>> & cells);
+ /**
+ * Given a vector of CellData objects describing a mesh, reorder their
+ * vertices so that all lines are consistently oriented.
+ *
+ * The expectations on orientation and a discussion of this function are
+ * available in the @ref reordering "reordering module".
+ *
+ * @param cells The array of CellData objects that describe the mesh's topology.
+ */
+ template <int dim>
+ void
+ consistently_order_cells(std::vector<CellData<dim>> &cells);
+
/*@}*/
/**
* @name Rotating, stretching and otherwise transforming meshes
<< "The given vertex with index " << arg1
<< " is not used in the given triangulation.");
-
/*@}*/
} /*namespace GridTools*/
+/**
+ * An exception that is thrown whenever the edges of a mesh are not
+ * orientable.
+ *
+ * @note for backwards compatibility with the old GridReordering class this
+ * exception is not in the GridTools namespace.
+ *
+ * @ingroup Exceptions
+ */
+DeclExceptionMsg(ExcMeshNotOrientable,
+ "The edges of the mesh are not consistently orientable.");
+
+
/* ----------------- Template function --------------- */
cells[15].vertices[3] = 2;
cells[15].material_id = 0;
- // Must call this to be able to create a
- // correct triangulation in dealii, read
- // GridReordering<> doc
- GridReordering<dim, spacedim>::reorder_cells(cells, true);
+ GridTools::consistently_order_cells(cells);
tria.create_triangulation(vertices, cells, SubCellData());
tria.set_all_manifold_ids(0);
// Parallelepiped implementation in 1d, 2d, and 3d. @note The
// implementation in 1d is similar to hyper_rectangle(), and in 2d is
// similar to parallelogram().
- //
- // The GridReordering::reorder_grid is made use of towards the end of
- // this function. Thus the triangulation is explicitly constructed for
- // all dim here since it is slightly different in that respect
- // (cf. hyper_rectangle(), parallelogram()).
template <int dim, int spacedim>
void
subdivided_parallelepiped(Triangulation<dim, spacedim> & tria,
// Create triangulation
// reorder the cells to ensure that they satisfy the convention for
// edge and face directions
- GridReordering<dim>::reorder_cells(cells, true);
+ GridTools::consistently_order_cells(cells);
tria.create_triangulation(points, cells, SubCellData());
// Finally assign boundary indicators according to hyper_rectangle
// reorder the cells to ensure that they satisfy the convention for
// edge and face directions
- GridReordering<dim, spacedim>::reorder_cells(cells, true);
+ GridTools::consistently_order_cells(cells);
result.clear();
result.create_triangulation(vertices, cells, subcell_data);
}
1e-6 * input.begin_active()->diameter());
// delete_duplicated_vertices also deletes any unused vertices
// deal with any reordering issues created by delete_duplicated_vertices
- GridReordering<dim>::reorder_cells(output_cell_data, true);
+ GridTools::consistently_order_cells(output_cell_data);
// clean up the boundary ids of the boundary objects: note that we
// have to do this after delete_duplicated_vertices so that boundary
// objects are actually duplicated at this point
// use all of this to finally create the extruded 3d
// triangulation. it is not necessary to call
- // GridReordering<3,3>::reorder_cells because the cells we have
+ // GridTools::consistently_order_cells() because the cells we have
// constructed above are automatically correctly oriented. this is
// because the 2d base mesh is always correctly oriented, and
// extruding it automatically yields a correctly oriented 3d mesh,
// as discussed in the edge orientation paper mentioned in the
- // introduction to the GridReordering class.
+ // introduction to the @ref reordering "reordering module".
result.create_triangulation(points, cells, subcell_data);
for (auto manifold_id_it = priorities.rbegin();
// TODO: the functions below (GridTools::delete_unused_vertices(),
// GridTools::invert_all_negative_measure_cells(),
- // GridReordering::reorder_cells()) need to be
+ // GridTools::consistently_order_cells()) need to be
// revisited for simplex/mixed meshes
if (dim == 1 || (is_quad_or_hex_mesh && !is_tria_or_tet_mesh))
if (dim == spacedim)
GridTools::invert_all_negative_measure_cells(vertices, cells);
- GridReordering<dim, spacedim>::reorder_cells(cells, true);
+ GridTools::consistently_order_cells(cells);
tria->create_triangulation(vertices, cells, subcelldata);
}
else
if (dim == spacedim)
GridTools::invert_all_negative_measure_cells(vertices, cells);
- GridReordering<dim, spacedim>::reorder_cells(cells, true);
+ GridTools::consistently_order_cells(cells);
tria->create_triangulation(vertices, cells, subcelldata);
}
// ... and cells
if (dim == spacedim)
GridTools::invert_all_negative_measure_cells(vertices, cells);
- GridReordering<dim, spacedim>::reorder_cells(cells, true);
+ GridTools::consistently_order_cells(cells);
tria->create_triangulation(vertices, cells, subcelldata);
}
GridTools::delete_unused_vertices(vertices, cells, subcelldata);
// ...and cells
GridTools::invert_all_negative_measure_cells(vertices, cells);
- GridReordering<dim, spacedim>::reorder_cells(cells, true);
+ GridTools::consistently_order_cells(cells);
tria->create_triangulation(vertices, cells, subcelldata);
}
GridTools::delete_unused_vertices(vertices, cells, subcelldata);
// ... and cells
GridTools::invert_all_negative_measure_cells(vertices, cells);
- GridReordering<dim>::reorder_cells(cells, true);
+ GridTools::consistently_order_cells(cells);
tria->create_triangulation(vertices, cells, subcelldata);
}
// TODO: the functions below (GridTools::delete_unused_vertices(),
// GridTools::invert_all_negative_measure_cells(),
- // GridReordering::reorder_cells()) need to be revisited
+ // GridTools::consistently_order_cells()) need to be revisited
// for simplex/mixed meshes
if (dim == 1 || (is_quad_or_hex_mesh && !is_tria_or_tet_mesh))
// ... and cells
if (dim == spacedim)
GridTools::invert_all_negative_measure_cells(vertices, cells);
- GridReordering<dim, spacedim>::reorder_cells(cells, true);
+ GridTools::consistently_order_cells(cells);
}
tria->create_triangulation(vertices, cells, subcelldata);
// do some cleanup on cells
GridTools::invert_all_negative_measure_cells(vertices, cells);
- GridReordering<dim, spacedim>::reorder_cells(cells, true);
+ GridTools::consistently_order_cells(cells);
tria->create_triangulation(vertices, cells, subcelldata);
}
GridTools::delete_unused_vertices(vertices, cells, subcelldata);
if (dim == spacedim)
GridTools::invert_all_negative_measure_cells(vertices, cells);
- GridReordering<dim, spacedim>::reorder_cells(cells, true);
+ GridTools::consistently_order_cells(cells);
tria->create_triangulation(vertices, cells, subcelldata);
#else
DEAL_II_NAMESPACE_OPEN
-namespace
-{
- /**
- * A simple data structure denoting an edge, i.e., the ordered pair
- * of its vertex indices. This is only used in the is_consistent()
- * function.
- */
- struct CheapEdge
- {
- /**
- * Construct an edge from the global indices of its two vertices.
- */
- CheapEdge(const unsigned int v0, const unsigned int v1)
- : v0(v0)
- , v1(v1)
- {}
-
- /**
- * Comparison operator for edges. It compares based on the
- * lexicographic ordering of the two vertex indices.
- */
- bool
- operator<(const CheapEdge &e) const
- {
- return ((v0 < e.v0) || ((v0 == e.v0) && (v1 < e.v1)));
- }
-
- private:
- /**
- * The global indices of the vertices that define the edge.
- */
- const unsigned int v0, v1;
- };
-
-
- /**
- * A function that determines whether the edges in a mesh are
- * already consistently oriented. It does so by adding all edges
- * of all cells into a set (which automatically eliminates
- * duplicates) but before that checks whether the reverse edge is
- * already in the set -- which would imply that a neighboring cell
- * is inconsistently oriented.
- */
- template <int dim>
- bool
- is_consistent(const std::vector<CellData<dim>> &cells)
- {
- std::set<CheapEdge> edges;
-
- for (typename std::vector<CellData<dim>>::const_iterator c = cells.begin();
- c != cells.end();
- ++c)
- {
- // construct the edges in reverse order. for each of them,
- // ensure that the reverse edge is not yet in the list of
- // edges (return false if the reverse edge already *is* in
- // the list) and then add the actual edge to it; std::set
- // eliminates duplicates automatically
- for (unsigned int l = 0; l < GeometryInfo<dim>::lines_per_cell; ++l)
- {
- const CheapEdge reverse_edge(
- c->vertices[GeometryInfo<dim>::line_to_cell_vertices(l, 1)],
- c->vertices[GeometryInfo<dim>::line_to_cell_vertices(l, 0)]);
- if (edges.find(reverse_edge) != edges.end())
- return false;
-
-
- // ok, not. insert edge in correct order
- const CheapEdge correct_edge(
- c->vertices[GeometryInfo<dim>::line_to_cell_vertices(l, 0)],
- c->vertices[GeometryInfo<dim>::line_to_cell_vertices(l, 1)]);
- edges.insert(correct_edge);
- }
- }
-
- // no conflicts found, so return true
- return true;
- }
-
-
- /**
- * A structure that describes some properties of parallel edges
- * such as what starter edges are (i.e., representative elements
- * of the sets of parallel edges within a cell) and what the set
- * of parallel edges to each edge is.
- */
- template <int dim>
- struct ParallelEdges
- {
- /**
- * An array that contains the indices of dim edges that can
- * serve as (arbitrarily chosen) starting points for the
- * dim sets of parallel edges within each cell.
- */
- static const unsigned int starter_edges[dim];
-
- /**
- * Number and indices of all of those edges parallel to each of the
- * edges in a cell.
- */
- static const unsigned int n_other_parallel_edges = (1 << (dim - 1)) - 1;
- static const unsigned int parallel_edges[GeometryInfo<dim>::lines_per_cell]
- [n_other_parallel_edges];
- };
-
- template <>
- const unsigned int ParallelEdges<2>::starter_edges[2] = {0, 2};
-
- template <>
- const unsigned int ParallelEdges<2>::parallel_edges[4][1] = {{1},
- {0},
- {3},
- {2}};
-
- template <>
- const unsigned int ParallelEdges<3>::starter_edges[3] = {0, 2, 8};
-
- template <>
- const unsigned int ParallelEdges<3>::parallel_edges[12][3] = {
- {1, 4, 5}, // line 0
- {0, 4, 5}, // line 1
- {3, 6, 7}, // line 2
- {2, 6, 7}, // line 3
- {0, 1, 5}, // line 4
- {0, 1, 4}, // line 5
- {2, 3, 7}, // line 6
- {2, 3, 6}, // line 7
- {9, 10, 11}, // line 8
- {8, 10, 11}, // line 9
- {8, 9, 11}, // line 10
- {8, 9, 10} // line 11
- };
-
-
- /**
- * A structure that store the index of a cell and, crucially, how a
- * given edge relates to this cell.
- */
- struct AdjacentCell
- {
- /**
- * Default constructor. Initialize the fields with invalid values.
- */
- AdjacentCell()
- : cell_index(numbers::invalid_unsigned_int)
- , edge_within_cell(numbers::invalid_unsigned_int)
- {}
-
- /**
- * Constructor. Initialize the fields with the given values.
- */
- AdjacentCell(const unsigned int cell_index,
- const unsigned int edge_within_cell)
- : cell_index(cell_index)
- , edge_within_cell(edge_within_cell)
- {}
-
-
- unsigned int cell_index;
- unsigned int edge_within_cell;
- };
-
-
-
- template <int dim>
- class AdjacentCells;
-
- /**
- * A class that represents all of the cells adjacent to a given edge.
- * This class corresponds to the 2d case where each edge has at most
- * two adjacent cells.
- */
- template <>
- class AdjacentCells<2>
- {
- public:
- /**
- * An iterator that allows iterating over all cells adjacent
- * to the edge represented by the current object.
- */
- using const_iterator = const AdjacentCell *;
-
- /**
- * Add the given cell to the collection of cells adjacent to
- * the edge this object corresponds to. Since we are covering
- * the 2d case, the set of adjacent cells currently
- * represented by this object must have either zero or
- * one element already, since we can not add more than two
- * adjacent cells for each edge.
- */
- void
- push_back(const AdjacentCell &adjacent_cell)
- {
- if (adjacent_cells[0].cell_index == numbers::invalid_unsigned_int)
- adjacent_cells[0] = adjacent_cell;
- else
- {
- Assert(adjacent_cells[1].cell_index == numbers::invalid_unsigned_int,
- ExcInternalError());
- adjacent_cells[1] = adjacent_cell;
- }
- }
-
-
- /**
- * Return an iterator to the first valid cell stored as adjacent to the
- * edge represented by the current object.
- */
- const_iterator
- begin() const
- {
- return adjacent_cells;
- }
-
-
- /**
- * Return an iterator to the element past the last valid cell stored
- * as adjacent to the edge represented by the current object.
- * @return
- */
- const_iterator
- end() const
- {
- // check whether the current object stores zero, one, or two
- // adjacent cells, and use this to point to the element past the
- // last valid one
- if (adjacent_cells[0].cell_index == numbers::invalid_unsigned_int)
- return adjacent_cells;
- else if (adjacent_cells[1].cell_index == numbers::invalid_unsigned_int)
- return adjacent_cells + 1;
- else
- return adjacent_cells + 2;
- }
-
- private:
- /**
- * References to the (at most) two cells that are adjacent to
- * the edge this object corresponds to. Unused elements are
- * default-initialized and have invalid values; in particular,
- * their cell_index field equals numbers::invalid_unsigned_int.
- */
- AdjacentCell adjacent_cells[2];
- };
-
-
-
- /**
- * A class that represents all of the cells adjacent to a given edge.
- * This class corresponds to the 3d case where each edge can have an
- * arbitrary number of adjacent cells. We represent this as a
- * std::vector<AdjacentCell>, from which class the current one is
- * derived and from which it inherits all of its member functions.
- */
- template <>
- class AdjacentCells<3> : public std::vector<AdjacentCell>
- {};
-
-
- /**
- * A class that describes all of the relevant properties of an
- * edge. For the purpose of what we do here, that includes the
- * indices of the two vertices, and the indices of the adjacent
- * cells (together with a description *where* in each of the
- * adjacent cells the edge is located). It also includes the
- * (global) direction of the edge: either from the first vertex to
- * the second, the other way around, or so far undetermined.
- */
- template <int dim>
- class Edge
- {
- public:
- /**
- * Constructor. Create the edge based on the information given
- * in @p cell, and selecting the edge with number @p edge_number
- * within this cell. Initialize the edge as unoriented.
- */
- Edge(const CellData<dim> &cell, const unsigned int edge_number)
- : orientation_status(not_oriented)
- {
- Assert(edge_number < GeometryInfo<dim>::lines_per_cell,
- ExcInternalError());
-
- // copy vertices for this particular line
- vertex_indices[0] =
- cell.vertices[GeometryInfo<dim>::line_to_cell_vertices(edge_number, 0)];
- vertex_indices[1] =
- cell.vertices[GeometryInfo<dim>::line_to_cell_vertices(edge_number, 1)];
-
- // bring them into standard orientation
- if (vertex_indices[0] > vertex_indices[1])
- std::swap(vertex_indices[0], vertex_indices[1]);
- }
-
- /**
- * Comparison operator for edges. It compares based on the
- * lexicographic ordering of the two vertex indices.
- */
- bool
- operator<(const Edge<dim> &e) const
- {
- return ((vertex_indices[0] < e.vertex_indices[0]) ||
- ((vertex_indices[0] == e.vertex_indices[0]) &&
- (vertex_indices[1] < e.vertex_indices[1])));
- }
-
- /**
- * Compare two edges for equality based on their vertex indices.
- */
- bool
- operator==(const Edge<dim> &e) const
- {
- return ((vertex_indices[0] == e.vertex_indices[0]) &&
- (vertex_indices[1] == e.vertex_indices[1]));
- }
-
- /**
- * The global indices of the two vertices that bound this edge. These
- * will be ordered so that the first index is less than the second.
- */
- unsigned int vertex_indices[2];
-
- /**
- * An enum that indicates the direction of this edge with
- * regard to the two vertices that bound it.
- */
- enum OrientationStatus
- {
- not_oriented,
- forward,
- backward
- };
-
- OrientationStatus orientation_status;
-
- /**
- * Store the set of cells adjacent to this edge (these cells then
- * also store *where* in the cell the edge is located).
- */
- AdjacentCells<dim> adjacent_cells;
- };
-
-
-
- /**
- * A data structure that represents a cell with all of its vertices
- * and edges.
- */
- template <int dim>
- struct Cell
- {
- /**
- * Construct a Cell object from a CellData object. Also take a
- * (sorted) list of edges and to point the edges of the current
- * object into this list of edges.
- */
- Cell(const CellData<dim> &c, const std::vector<Edge<dim>> &edge_list)
- {
- for (const unsigned int i : GeometryInfo<dim>::vertex_indices())
- vertex_indices[i] = c.vertices[i];
-
- // now for each of the edges of this cell, find the location inside the
- // given edge_list array and store than index
- for (unsigned int l = 0; l < GeometryInfo<dim>::lines_per_cell; ++l)
- {
- const Edge<dim> e(c, l);
- edge_indices[l] =
- (std::lower_bound(edge_list.begin(), edge_list.end(), e) -
- edge_list.begin());
- Assert(edge_indices[l] < edge_list.size(), ExcInternalError());
- Assert(edge_list[edge_indices[l]] == e, ExcInternalError())
- }
- }
-
- /**
- * A list of global indices for the vertices that bound this cell.
- */
- unsigned int vertex_indices[GeometryInfo<dim>::vertices_per_cell];
-
- /**
- * A list of indices into the 'edge_list' array passed to the constructor
- * for the edges of the current cell.
- */
- unsigned int edge_indices[GeometryInfo<dim>::lines_per_cell];
- };
-
-
-
- template <int dim>
- class EdgeDeltaSet;
-
- /**
- * A class that represents by how much the set of parallel edges
- * grows in each step. In the graph orientation paper, this set is
- * called $\Delta_k$, thus the name.
- *
- * In 2d, this set can only include zero, one, or two elements.
- * Consequently, the appropriate data structure is one in which
- * we store at most 2 elements in a fixed sized data structure.
- */
- template <>
- class EdgeDeltaSet<2>
- {
- public:
- /**
- * Iterator type for the elements of the set.
- */
- using const_iterator = const unsigned int *;
-
- /**
- * Default constructor. Initialize both slots as unused, corresponding
- * to an empty set.
- */
- EdgeDeltaSet()
- {
- edge_indices[0] = edge_indices[1] = numbers::invalid_unsigned_int;
- }
-
-
- /**
- * Delete the elements of the set by marking both slots as unused.
- */
- void
- clear()
- {
- edge_indices[0] = edge_indices[1] = numbers::invalid_unsigned_int;
- }
-
- /**
- * Insert one element into the set. This will fail if the set already
- * has two elements.
- */
- void
- insert(const unsigned int edge_index)
- {
- if (edge_indices[0] == numbers::invalid_unsigned_int)
- edge_indices[0] = edge_index;
- else
- {
- Assert(edge_indices[1] == numbers::invalid_unsigned_int,
- ExcInternalError());
- edge_indices[1] = edge_index;
- }
- }
-
-
- /**
- * Return an iterator pointing to the first element of the set.
- */
- const_iterator
- begin() const
- {
- return edge_indices;
- }
-
-
- /**
- * Return an iterator pointing to the element past the last used one.
- */
- const_iterator
- end() const
- {
- // check whether the current object stores zero, one, or two
- // indices, and use this to point to the element past the
- // last valid one
- if (edge_indices[0] == numbers::invalid_unsigned_int)
- return edge_indices;
- else if (edge_indices[1] == numbers::invalid_unsigned_int)
- return edge_indices + 1;
- else
- return edge_indices + 2;
- }
-
- private:
- /**
- * Storage space to store the indices of at most two edges.
- */
- unsigned int edge_indices[2];
- };
-
-
-
- /**
- * A class that represents by how much the set of parallel edges
- * grows in each step. In the graph orientation paper, this set is
- * called $\Delta_k$, thus the name.
- *
- * In 3d, this set can have arbitrarily many elements, unlike the
- * 2d case specialized above. Consequently, we simply represent
- * the data structure with a std::set. Class derivation ensures
- * that we simply inherit all of the member functions of the
- * base class.
- */
- template <>
- class EdgeDeltaSet<3> : public std::set<unsigned int>
- {};
-
-
-
- /**
- * From a list of cells, build a sorted vector that contains all of the edges
- * that exist in the mesh.
- */
- template <int dim>
- std::vector<Edge<dim>>
- build_edges(const std::vector<CellData<dim>> &cells)
- {
- // build the edge list for all cells. because each cell has
- // GeometryInfo<dim>::lines_per_cell edges, the total number
- // of edges is this many times the number of cells. of course
- // some of them will be duplicates, and we throw them out below
- std::vector<Edge<dim>> edge_list;
- edge_list.reserve(cells.size() * GeometryInfo<dim>::lines_per_cell);
- for (unsigned int i = 0; i < cells.size(); ++i)
- for (unsigned int l = 0; l < GeometryInfo<dim>::lines_per_cell; ++l)
- edge_list.emplace_back(cells[i], l);
-
- // next sort the edge list and then remove duplicates
- std::sort(edge_list.begin(), edge_list.end());
- edge_list.erase(std::unique(edge_list.begin(), edge_list.end()),
- edge_list.end());
-
- return edge_list;
- }
-
-
-
- /**
- * Build the cell list. Update the edge array to let edges know
- * which cells are adjacent to them.
- */
- template <int dim>
- std::vector<Cell<dim>>
- build_cells_and_connect_edges(const std::vector<CellData<dim>> &cells,
- std::vector<Edge<dim>> & edges)
- {
- std::vector<Cell<dim>> cell_list;
- cell_list.reserve(cells.size());
- for (unsigned int i = 0; i < cells.size(); ++i)
- {
- // create our own data structure for the cells and let it
- // connect to the edges array
- cell_list.emplace_back(cells[i], edges);
-
- // then also inform the edges that they are adjacent
- // to the current cell, and where within this cell
- for (unsigned int l = 0; l < GeometryInfo<dim>::lines_per_cell; ++l)
- edges[cell_list.back().edge_indices[l]].adjacent_cells.push_back(
- AdjacentCell(i, l));
- }
- Assert(cell_list.size() == cells.size(), ExcInternalError());
-
- return cell_list;
- }
-
-
-
- /**
- * Return the index within 'cells' of the first cell that has at least one
- * edge that is not yet oriented.
- */
- template <int dim>
- unsigned int
- get_next_unoriented_cell(const std::vector<Cell<dim>> &cells,
- const std::vector<Edge<dim>> &edges,
- const unsigned int current_cell)
- {
- for (unsigned int c = current_cell; c < cells.size(); ++c)
- for (unsigned int l = 0; l < GeometryInfo<dim>::lines_per_cell; ++l)
- if (edges[cells[c].edge_indices[l]].orientation_status ==
- Edge<dim>::not_oriented)
- return c;
-
- return numbers::invalid_unsigned_int;
- }
-
-
-
- /**
- * Given a set of cells and edges, orient all edges that are
- * (global) parallel to the one identified by the @p cell and
- * within it the one with index @p local_edge.
- */
- template <int dim>
- void
- orient_one_set_of_parallel_edges(const std::vector<Cell<dim>> &cells,
- std::vector<Edge<dim>> & edges,
- const unsigned int cell,
- const unsigned int local_edge)
- {
- // choose the direction of the first edge. we have free choice
- // here and could simply choose "forward" if that's what pleases
- // us. however, for backward compatibility with the previous
- // implementation used till 2016, let us just choose the
- // direction so that it matches what we have in the given cell.
- //
- // in fact, in what can only be assumed to be a bug in the
- // original implementation, after orienting all edges, the code
- // that rotates the cells so that they match edge orientations
- // (see the rotate_cell() function below) rotated the cell two
- // more times by 90 degrees. this is ok -- it simply flips all
- // edge orientations, which leaves them valid. rather than do
- // the same in the current implementation, we can achieve the
- // same effect by modifying the rule above to choose the
- // direction of the starting edge of this parallel set
- // *opposite* to what it looks like in the current cell
- //
- // this bug only existed in the 2d implementation since there
- // were different implementations for 2d and 3d. consequently,
- // only replicate it for the 2d case and be "intuitive" in 3d.
- if (edges[cells[cell].edge_indices[local_edge]].vertex_indices[0] ==
- cells[cell].vertex_indices[GeometryInfo<dim>::line_to_cell_vertices(
- local_edge, 0)])
- // orient initial edge *opposite* to the way it is in the cell
- // (see above for the reason)
- edges[cells[cell].edge_indices[local_edge]].orientation_status =
- (dim == 2 ? Edge<dim>::backward : Edge<dim>::forward);
- else
- {
- Assert(
- edges[cells[cell].edge_indices[local_edge]].vertex_indices[0] ==
- cells[cell].vertex_indices[GeometryInfo<dim>::line_to_cell_vertices(
- local_edge, 1)],
- ExcInternalError());
- Assert(
- edges[cells[cell].edge_indices[local_edge]].vertex_indices[1] ==
- cells[cell].vertex_indices[GeometryInfo<dim>::line_to_cell_vertices(
- local_edge, 0)],
- ExcInternalError());
-
- // orient initial edge *opposite* to the way it is in the cell
- // (see above for the reason)
- edges[cells[cell].edge_indices[local_edge]].orientation_status =
- (dim == 2 ? Edge<dim>::forward : Edge<dim>::backward);
- }
-
- // walk outward from the given edge as described in
- // the algorithm in the paper that documents all of
- // this
- //
- // note that in 2d, each of the Deltas can at most
- // contain two elements, whereas in 3d it can be arbitrarily many
- EdgeDeltaSet<dim> Delta_k;
- EdgeDeltaSet<dim> Delta_k_minus_1;
- Delta_k_minus_1.insert(cells[cell].edge_indices[local_edge]);
-
- while (Delta_k_minus_1.begin() !=
- Delta_k_minus_1.end()) // while set is not empty
- {
- Delta_k.clear();
-
- for (typename EdgeDeltaSet<dim>::const_iterator delta =
- Delta_k_minus_1.begin();
- delta != Delta_k_minus_1.end();
- ++delta)
- {
- Assert(edges[*delta].orientation_status != Edge<dim>::not_oriented,
- ExcInternalError());
-
- // now go through the cells adjacent to this edge
- for (typename AdjacentCells<dim>::const_iterator adjacent_cell =
- edges[*delta].adjacent_cells.begin();
- adjacent_cell != edges[*delta].adjacent_cells.end();
- ++adjacent_cell)
- {
- const unsigned int K = adjacent_cell->cell_index;
- const unsigned int delta_is_edge_in_K =
- adjacent_cell->edge_within_cell;
-
- // figure out the direction of delta with respect to the cell K
- // (in the orientation in which the user has given it to us)
- const unsigned int first_edge_vertex =
- (edges[*delta].orientation_status == Edge<dim>::forward ?
- edges[*delta].vertex_indices[0] :
- edges[*delta].vertex_indices[1]);
- const unsigned int first_edge_vertex_in_K =
- cells[K]
- .vertex_indices[GeometryInfo<dim>::line_to_cell_vertices(
- delta_is_edge_in_K, 0)];
- Assert(
- first_edge_vertex == first_edge_vertex_in_K ||
- first_edge_vertex ==
- cells[K].vertex_indices[GeometryInfo<
- dim>::line_to_cell_vertices(delta_is_edge_in_K, 1)],
- ExcInternalError());
-
- // now figure out which direction the each of the "opposite"
- // edges needs to be oriented into.
- for (unsigned int o_e = 0;
- o_e < ParallelEdges<dim>::n_other_parallel_edges;
- ++o_e)
- {
- // get the index of the opposite edge and select which its
- // first vertex needs to be based on how the current edge is
- // oriented in the current cell
- const unsigned int opposite_edge =
- cells[K].edge_indices[ParallelEdges<
- dim>::parallel_edges[delta_is_edge_in_K][o_e]];
- const unsigned int first_opposite_edge_vertex =
- cells[K].vertex_indices
- [GeometryInfo<dim>::line_to_cell_vertices(
- ParallelEdges<dim>::parallel_edges[delta_is_edge_in_K]
- [o_e],
- (first_edge_vertex == first_edge_vertex_in_K ? 0 :
- 1))];
-
- // then determine the orientation of the edge based on
- // whether the vertex we want to be the edge's first
- // vertex is already the first vertex of the edge, or
- // whether it points in the opposite direction
- const typename Edge<dim>::OrientationStatus
- opposite_edge_orientation =
- (edges[opposite_edge].vertex_indices[0] ==
- first_opposite_edge_vertex ?
- Edge<dim>::forward :
- Edge<dim>::backward);
-
- // see if the opposite edge (there is only one in 2d) has
- // already been oriented.
- if (edges[opposite_edge].orientation_status ==
- Edge<dim>::not_oriented)
- {
- // the opposite edge is not yet oriented. do orient it
- // and add it to Delta_k
- edges[opposite_edge].orientation_status =
- opposite_edge_orientation;
- Delta_k.insert(opposite_edge);
- }
- else
- {
- // this opposite edge has already been oriented. it
- // should be consistent with the current one in 2d,
- // while in 3d it may in fact be mis-oriented, and in
- // that case the mesh will not be orientable. indicate
- // this by throwing an exception that we can catch
- // further up; this has the advantage that we can
- // propagate through a couple of functions without
- // having to do error checking and without modifying the
- // 'cells' array that the user gave us
- if (dim == 2)
- {
- Assert(edges[opposite_edge].orientation_status ==
- opposite_edge_orientation,
- ExcMeshNotOrientable());
- }
- else if (dim == 3)
- {
- if (edges[opposite_edge].orientation_status !=
- opposite_edge_orientation)
- throw ExcMeshNotOrientable();
- }
- else
- Assert(false, ExcNotImplemented());
- }
- }
- }
- }
-
- // finally copy the new set to the previous one
- // (corresponding to increasing 'k' by one in the
- // algorithm)
- Delta_k_minus_1 = Delta_k;
- }
- }
-
-
- /**
- * Given data structures @p cell_list and @p edge_list, where
- * all edges are already oriented, rotate the cell with
- * index @p cell_index in such a way that its local coordinate
- * system matches the ones of the adjacent edges. Store the
- * rotated order of vertices in <code>raw_cells[cell_index]</code>.
- */
- template <int dim>
- void
- rotate_cell(const std::vector<Cell<dim>> &cell_list,
- const std::vector<Edge<dim>> &edge_list,
- const unsigned int cell_index,
- std::vector<CellData<dim>> & raw_cells)
- {
- // find the first vertex of the cell. this is the vertex where dim edges
- // originate, so for each of the edges record which the starting vertex is
- unsigned int starting_vertex_of_edge[GeometryInfo<dim>::lines_per_cell];
- for (unsigned int e = 0; e < GeometryInfo<dim>::lines_per_cell; ++e)
- {
- Assert(edge_list[cell_list[cell_index].edge_indices[e]]
- .orientation_status != Edge<dim>::not_oriented,
- ExcInternalError());
- if (edge_list[cell_list[cell_index].edge_indices[e]]
- .orientation_status == Edge<dim>::forward)
- starting_vertex_of_edge[e] =
- edge_list[cell_list[cell_index].edge_indices[e]].vertex_indices[0];
- else
- starting_vertex_of_edge[e] =
- edge_list[cell_list[cell_index].edge_indices[e]].vertex_indices[1];
- }
-
- // find the vertex number that appears dim times. this will then be
- // the vertex at which we want to locate the origin of the cell's
- // coordinate system (i.e., vertex 0)
- unsigned int origin_vertex_of_cell = numbers::invalid_unsigned_int;
- switch (dim)
- {
- case 2:
- {
- // in 2d, we can simply enumerate the possibilities where the
- // origin may be located because edges zero and one don't share
- // any vertices, and the same for edges two and three
- if ((starting_vertex_of_edge[0] == starting_vertex_of_edge[2]) ||
- (starting_vertex_of_edge[0] == starting_vertex_of_edge[3]))
- origin_vertex_of_cell = starting_vertex_of_edge[0];
- else if ((starting_vertex_of_edge[1] ==
- starting_vertex_of_edge[2]) ||
- (starting_vertex_of_edge[1] == starting_vertex_of_edge[3]))
- origin_vertex_of_cell = starting_vertex_of_edge[1];
- else
- Assert(false, ExcInternalError());
-
- break;
- }
-
- case 3:
- {
- // one could probably do something similar in 3d, but that seems
- // more complicated than one wants to write down. just go
- // through the list of possible starting vertices and check
- for (origin_vertex_of_cell = 0;
- origin_vertex_of_cell < GeometryInfo<dim>::vertices_per_cell;
- ++origin_vertex_of_cell)
- if (std::count(starting_vertex_of_edge,
- starting_vertex_of_edge +
- GeometryInfo<dim>::lines_per_cell,
- cell_list[cell_index]
- .vertex_indices[origin_vertex_of_cell]) == dim)
- break;
- Assert(origin_vertex_of_cell < GeometryInfo<dim>::vertices_per_cell,
- ExcInternalError());
-
- break;
- }
-
- default:
- Assert(false, ExcNotImplemented());
- }
-
- // now rotate raw_cells[cell_index] in such a way that its orientation
- // matches that of cell_list[cell_index]
- switch (dim)
- {
- case 2:
- {
- // in 2d, we can literally rotate the cell until its origin
- // matches the one that we have determined above should be
- // the origin vertex
- //
- // when doing a rotation, take into account the ordering of
- // vertices (not in clockwise or counter-clockwise sense)
- while (raw_cells[cell_index].vertices[0] != origin_vertex_of_cell)
- {
- const unsigned int tmp = raw_cells[cell_index].vertices[0];
- raw_cells[cell_index].vertices[0] =
- raw_cells[cell_index].vertices[1];
- raw_cells[cell_index].vertices[1] =
- raw_cells[cell_index].vertices[3];
- raw_cells[cell_index].vertices[3] =
- raw_cells[cell_index].vertices[2];
- raw_cells[cell_index].vertices[2] = tmp;
- }
- break;
- }
-
- case 3:
- {
- // in 3d, the situation is a bit more complicated. from above, we
- // now know which vertex is at the origin (because 3 edges originate
- // from it), but that still leaves 3 possible rotations of the cube.
- // the important realization is that we can choose any of them:
- // in all 3 rotations, all edges originate from the one vertex,
- // and that fixes the directions of all 12 edges in the cube because
- // these 3 cover all 3 equivalence classes! consequently, we can
- // select an arbitrary one among the permutations -- for
- // example the following ones:
- static const unsigned int cube_permutations[8][8] = {
- {0, 1, 2, 3, 4, 5, 6, 7},
- {1, 5, 3, 7, 0, 4, 2, 6},
- {2, 6, 0, 4, 3, 7, 1, 5},
- {3, 2, 1, 0, 7, 6, 5, 4},
- {4, 0, 6, 2, 5, 1, 7, 3},
- {5, 4, 7, 6, 1, 0, 3, 2},
- {6, 7, 4, 5, 2, 3, 0, 1},
- {7, 3, 5, 1, 6, 2, 4, 0}};
-
- unsigned int
- temp_vertex_indices[GeometryInfo<dim>::vertices_per_cell];
- for (const unsigned int v : GeometryInfo<dim>::vertex_indices())
- temp_vertex_indices[v] =
- raw_cells[cell_index]
- .vertices[cube_permutations[origin_vertex_of_cell][v]];
- for (const unsigned int v : GeometryInfo<dim>::vertex_indices())
- raw_cells[cell_index].vertices[v] = temp_vertex_indices[v];
-
- break;
- }
-
- default:
- {
- Assert(false, ExcNotImplemented());
- }
- }
- }
-
-
- /**
- * Given a set of cells, find globally unique edge orientations
- * and then rotate cells so that the coordinate system of the cell
- * coincides with the coordinate systems of the adjacent edges.
- */
- template <int dim>
- void
- reorient(std::vector<CellData<dim>> &cells)
- {
- // first build the arrays that connect cells to edges and the other
- // way around
- std::vector<Edge<dim>> edge_list = build_edges(cells);
- std::vector<Cell<dim>> cell_list =
- build_cells_and_connect_edges(cells, edge_list);
-
- // then loop over all cells and start orienting parallel edge sets
- // of cells that still have non-oriented edges
- unsigned int next_cell_with_unoriented_edge = 0;
- while ((next_cell_with_unoriented_edge = get_next_unoriented_cell(
- cell_list, edge_list, next_cell_with_unoriented_edge)) !=
- numbers::invalid_unsigned_int)
- {
- // see which edge sets are still not oriented
- //
- // we do not need to look at each edge because if we orient edge
- // 0, we will end up with edge 1 also oriented (in 2d; in 3d, there
- // will be 3 other edges that are also oriented). there are only
- // dim independent sets of edges, so loop over these.
- //
- // we need to check whether each one of these starter edges may
- // already be oriented because the line (sheet) that connects
- // globally parallel edges may be self-intersecting in the
- // current cell
- for (unsigned int l = 0; l < dim; ++l)
- if (edge_list[cell_list[next_cell_with_unoriented_edge]
- .edge_indices[ParallelEdges<dim>::starter_edges[l]]]
- .orientation_status == Edge<dim>::not_oriented)
- orient_one_set_of_parallel_edges(
- cell_list,
- edge_list,
- next_cell_with_unoriented_edge,
- ParallelEdges<dim>::starter_edges[l]);
-
- // ensure that we have really oriented all edges now, not just
- // the starter edges
- for (unsigned int l = 0; l < GeometryInfo<dim>::lines_per_cell; ++l)
- Assert(
- edge_list[cell_list[next_cell_with_unoriented_edge].edge_indices[l]]
- .orientation_status != Edge<dim>::not_oriented,
- ExcInternalError());
- }
-
- // now that we have oriented all edges, we need to rotate cells
- // so that the edges point in the right direction with the now
- // rotated coordinate system
- for (unsigned int c = 0; c < cells.size(); ++c)
- rotate_cell(cell_list, edge_list, c, cells);
- }
-
-
- // overload of the function above for 1d -- there is nothing
- // to orient in that case
- void reorient(std::vector<CellData<1>> &)
- {}
-} // namespace
-
-
// anonymous namespace for internal helper functions
namespace
{
if (use_new_style_ordering == false)
reorder_old_to_new_style(cells);
- // check if grids are already consistent. if so, do
- // nothing. if not, then do the reordering
- if (!is_consistent(cells))
- try
- {
- reorient(cells);
- }
- catch (const ExcMeshNotOrientable &)
- {
- // the mesh is not orientable. this is acceptable if we are in 3d,
- // as class Triangulation knows how to handle this, but it is
- // not in 2d; in that case, re-throw the exception
- if (dim < 3)
- throw;
- }
+ GridTools::consistently_order_cells(cells);
// and convert back if necessary
if (use_new_style_ordering == false)
+ // Functions and classes for consistently_order_cells
+ namespace
+ {
+ /**
+ * A simple data structure denoting an edge, i.e., the ordered pair
+ * of its vertex indices. This is only used in the is_consistent()
+ * function.
+ */
+ struct CheapEdge
+ {
+ /**
+ * Construct an edge from the global indices of its two vertices.
+ */
+ CheapEdge(const unsigned int v0, const unsigned int v1)
+ : v0(v0)
+ , v1(v1)
+ {}
+
+ /**
+ * Comparison operator for edges. It compares based on the
+ * lexicographic ordering of the two vertex indices.
+ */
+ bool
+ operator<(const CheapEdge &e) const
+ {
+ return ((v0 < e.v0) || ((v0 == e.v0) && (v1 < e.v1)));
+ }
+
+ private:
+ /**
+ * The global indices of the vertices that define the edge.
+ */
+ const unsigned int v0, v1;
+ };
+
+
+ /**
+ * A function that determines whether the edges in a mesh are
+ * already consistently oriented. It does so by adding all edges
+ * of all cells into a set (which automatically eliminates
+ * duplicates) but before that checks whether the reverse edge is
+ * already in the set -- which would imply that a neighboring cell
+ * is inconsistently oriented.
+ */
+ template <int dim>
+ bool
+ is_consistent(const std::vector<CellData<dim>> &cells)
+ {
+ std::set<CheapEdge> edges;
+
+ for (typename std::vector<CellData<dim>>::const_iterator c =
+ cells.begin();
+ c != cells.end();
+ ++c)
+ {
+ // construct the edges in reverse order. for each of them,
+ // ensure that the reverse edge is not yet in the list of
+ // edges (return false if the reverse edge already *is* in
+ // the list) and then add the actual edge to it; std::set
+ // eliminates duplicates automatically
+ for (unsigned int l = 0; l < GeometryInfo<dim>::lines_per_cell; ++l)
+ {
+ const CheapEdge reverse_edge(
+ c->vertices[GeometryInfo<dim>::line_to_cell_vertices(l, 1)],
+ c->vertices[GeometryInfo<dim>::line_to_cell_vertices(l, 0)]);
+ if (edges.find(reverse_edge) != edges.end())
+ return false;
+
+
+ // ok, not. insert edge in correct order
+ const CheapEdge correct_edge(
+ c->vertices[GeometryInfo<dim>::line_to_cell_vertices(l, 0)],
+ c->vertices[GeometryInfo<dim>::line_to_cell_vertices(l, 1)]);
+ edges.insert(correct_edge);
+ }
+ }
+
+ // no conflicts found, so return true
+ return true;
+ }
+
+
+ /**
+ * A structure that describes some properties of parallel edges
+ * such as what starter edges are (i.e., representative elements
+ * of the sets of parallel edges within a cell) and what the set
+ * of parallel edges to each edge is.
+ */
+ template <int dim>
+ struct ParallelEdges
+ {
+ /**
+ * An array that contains the indices of dim edges that can
+ * serve as (arbitrarily chosen) starting points for the
+ * dim sets of parallel edges within each cell.
+ */
+ static const unsigned int starter_edges[dim];
+
+ /**
+ * Number and indices of all of those edges parallel to each of the
+ * edges in a cell.
+ */
+ static const unsigned int n_other_parallel_edges = (1 << (dim - 1)) - 1;
+ static const unsigned int
+ parallel_edges[GeometryInfo<dim>::lines_per_cell]
+ [n_other_parallel_edges];
+ };
+
+ template <>
+ const unsigned int ParallelEdges<2>::starter_edges[2] = {0, 2};
+
+ template <>
+ const unsigned int ParallelEdges<2>::parallel_edges[4][1] = {{1},
+ {0},
+ {3},
+ {2}};
+
+ template <>
+ const unsigned int ParallelEdges<3>::starter_edges[3] = {0, 2, 8};
+
+ template <>
+ const unsigned int ParallelEdges<3>::parallel_edges[12][3] = {
+ {1, 4, 5}, // line 0
+ {0, 4, 5}, // line 1
+ {3, 6, 7}, // line 2
+ {2, 6, 7}, // line 3
+ {0, 1, 5}, // line 4
+ {0, 1, 4}, // line 5
+ {2, 3, 7}, // line 6
+ {2, 3, 6}, // line 7
+ {9, 10, 11}, // line 8
+ {8, 10, 11}, // line 9
+ {8, 9, 11}, // line 10
+ {8, 9, 10} // line 11
+ };
+
+
+ /**
+ * A structure that store the index of a cell and, crucially, how a
+ * given edge relates to this cell.
+ */
+ struct AdjacentCell
+ {
+ /**
+ * Default constructor. Initialize the fields with invalid values.
+ */
+ AdjacentCell()
+ : cell_index(numbers::invalid_unsigned_int)
+ , edge_within_cell(numbers::invalid_unsigned_int)
+ {}
+
+ /**
+ * Constructor. Initialize the fields with the given values.
+ */
+ AdjacentCell(const unsigned int cell_index,
+ const unsigned int edge_within_cell)
+ : cell_index(cell_index)
+ , edge_within_cell(edge_within_cell)
+ {}
+
+
+ unsigned int cell_index;
+ unsigned int edge_within_cell;
+ };
+
+
+
+ template <int dim>
+ class AdjacentCells;
+
+ /**
+ * A class that represents all of the cells adjacent to a given edge.
+ * This class corresponds to the 2d case where each edge has at most
+ * two adjacent cells.
+ */
+ template <>
+ class AdjacentCells<2>
+ {
+ public:
+ /**
+ * An iterator that allows iterating over all cells adjacent
+ * to the edge represented by the current object.
+ */
+ using const_iterator = const AdjacentCell *;
+
+ /**
+ * Add the given cell to the collection of cells adjacent to
+ * the edge this object corresponds to. Since we are covering
+ * the 2d case, the set of adjacent cells currently
+ * represented by this object must have either zero or
+ * one element already, since we can not add more than two
+ * adjacent cells for each edge.
+ */
+ void
+ push_back(const AdjacentCell &adjacent_cell)
+ {
+ if (adjacent_cells[0].cell_index == numbers::invalid_unsigned_int)
+ adjacent_cells[0] = adjacent_cell;
+ else
+ {
+ Assert(adjacent_cells[1].cell_index ==
+ numbers::invalid_unsigned_int,
+ ExcInternalError());
+ adjacent_cells[1] = adjacent_cell;
+ }
+ }
+
+
+ /**
+ * Return an iterator to the first valid cell stored as adjacent to the
+ * edge represented by the current object.
+ */
+ const_iterator
+ begin() const
+ {
+ return adjacent_cells;
+ }
+
+
+ /**
+ * Return an iterator to the element past the last valid cell stored
+ * as adjacent to the edge represented by the current object.
+ * @return
+ */
+ const_iterator
+ end() const
+ {
+ // check whether the current object stores zero, one, or two
+ // adjacent cells, and use this to point to the element past the
+ // last valid one
+ if (adjacent_cells[0].cell_index == numbers::invalid_unsigned_int)
+ return adjacent_cells;
+ else if (adjacent_cells[1].cell_index == numbers::invalid_unsigned_int)
+ return adjacent_cells + 1;
+ else
+ return adjacent_cells + 2;
+ }
+
+ private:
+ /**
+ * References to the (at most) two cells that are adjacent to
+ * the edge this object corresponds to. Unused elements are
+ * default-initialized and have invalid values; in particular,
+ * their cell_index field equals numbers::invalid_unsigned_int.
+ */
+ AdjacentCell adjacent_cells[2];
+ };
+
+
+
+ /**
+ * A class that represents all of the cells adjacent to a given edge.
+ * This class corresponds to the 3d case where each edge can have an
+ * arbitrary number of adjacent cells. We represent this as a
+ * std::vector<AdjacentCell>, from which class the current one is
+ * derived and from which it inherits all of its member functions.
+ */
+ template <>
+ class AdjacentCells<3> : public std::vector<AdjacentCell>
+ {};
+
+
+ /**
+ * A class that describes all of the relevant properties of an
+ * edge. For the purpose of what we do here, that includes the
+ * indices of the two vertices, and the indices of the adjacent
+ * cells (together with a description *where* in each of the
+ * adjacent cells the edge is located). It also includes the
+ * (global) direction of the edge: either from the first vertex to
+ * the second, the other way around, or so far undetermined.
+ */
+ template <int dim>
+ class Edge
+ {
+ public:
+ /**
+ * Constructor. Create the edge based on the information given
+ * in @p cell, and selecting the edge with number @p edge_number
+ * within this cell. Initialize the edge as unoriented.
+ */
+ Edge(const CellData<dim> &cell, const unsigned int edge_number)
+ : orientation_status(not_oriented)
+ {
+ Assert(edge_number < GeometryInfo<dim>::lines_per_cell,
+ ExcInternalError());
+
+ // copy vertices for this particular line
+ vertex_indices[0] =
+ cell
+ .vertices[GeometryInfo<dim>::line_to_cell_vertices(edge_number, 0)];
+ vertex_indices[1] =
+ cell
+ .vertices[GeometryInfo<dim>::line_to_cell_vertices(edge_number, 1)];
+
+ // bring them into standard orientation
+ if (vertex_indices[0] > vertex_indices[1])
+ std::swap(vertex_indices[0], vertex_indices[1]);
+ }
+
+ /**
+ * Comparison operator for edges. It compares based on the
+ * lexicographic ordering of the two vertex indices.
+ */
+ bool
+ operator<(const Edge<dim> &e) const
+ {
+ return ((vertex_indices[0] < e.vertex_indices[0]) ||
+ ((vertex_indices[0] == e.vertex_indices[0]) &&
+ (vertex_indices[1] < e.vertex_indices[1])));
+ }
+
+ /**
+ * Compare two edges for equality based on their vertex indices.
+ */
+ bool
+ operator==(const Edge<dim> &e) const
+ {
+ return ((vertex_indices[0] == e.vertex_indices[0]) &&
+ (vertex_indices[1] == e.vertex_indices[1]));
+ }
+
+ /**
+ * The global indices of the two vertices that bound this edge. These
+ * will be ordered so that the first index is less than the second.
+ */
+ unsigned int vertex_indices[2];
+
+ /**
+ * An enum that indicates the direction of this edge with
+ * regard to the two vertices that bound it.
+ */
+ enum OrientationStatus
+ {
+ not_oriented,
+ forward,
+ backward
+ };
+
+ OrientationStatus orientation_status;
+
+ /**
+ * Store the set of cells adjacent to this edge (these cells then
+ * also store *where* in the cell the edge is located).
+ */
+ AdjacentCells<dim> adjacent_cells;
+ };
+
+
+
+ /**
+ * A data structure that represents a cell with all of its vertices
+ * and edges.
+ */
+ template <int dim>
+ struct Cell
+ {
+ /**
+ * Construct a Cell object from a CellData object. Also take a
+ * (sorted) list of edges and to point the edges of the current
+ * object into this list of edges.
+ */
+ Cell(const CellData<dim> &c, const std::vector<Edge<dim>> &edge_list)
+ {
+ for (const unsigned int i : GeometryInfo<dim>::vertex_indices())
+ vertex_indices[i] = c.vertices[i];
+
+ // now for each of the edges of this cell, find the location inside the
+ // given edge_list array and store than index
+ for (unsigned int l = 0; l < GeometryInfo<dim>::lines_per_cell; ++l)
+ {
+ const Edge<dim> e(c, l);
+ edge_indices[l] =
+ (std::lower_bound(edge_list.begin(), edge_list.end(), e) -
+ edge_list.begin());
+ Assert(edge_indices[l] < edge_list.size(), ExcInternalError());
+ Assert(edge_list[edge_indices[l]] == e, ExcInternalError())
+ }
+ }
+
+ /**
+ * A list of global indices for the vertices that bound this cell.
+ */
+ unsigned int vertex_indices[GeometryInfo<dim>::vertices_per_cell];
+
+ /**
+ * A list of indices into the 'edge_list' array passed to the constructor
+ * for the edges of the current cell.
+ */
+ unsigned int edge_indices[GeometryInfo<dim>::lines_per_cell];
+ };
+
+
+
+ template <int dim>
+ class EdgeDeltaSet;
+
+ /**
+ * A class that represents by how much the set of parallel edges
+ * grows in each step. In the graph orientation paper, this set is
+ * called $\Delta_k$, thus the name.
+ *
+ * In 2d, this set can only include zero, one, or two elements.
+ * Consequently, the appropriate data structure is one in which
+ * we store at most 2 elements in a fixed sized data structure.
+ */
+ template <>
+ class EdgeDeltaSet<2>
+ {
+ public:
+ /**
+ * Iterator type for the elements of the set.
+ */
+ using const_iterator = const unsigned int *;
+
+ /**
+ * Default constructor. Initialize both slots as unused, corresponding
+ * to an empty set.
+ */
+ EdgeDeltaSet()
+ {
+ edge_indices[0] = edge_indices[1] = numbers::invalid_unsigned_int;
+ }
+
+
+ /**
+ * Delete the elements of the set by marking both slots as unused.
+ */
+ void
+ clear()
+ {
+ edge_indices[0] = edge_indices[1] = numbers::invalid_unsigned_int;
+ }
+
+ /**
+ * Insert one element into the set. This will fail if the set already
+ * has two elements.
+ */
+ void
+ insert(const unsigned int edge_index)
+ {
+ if (edge_indices[0] == numbers::invalid_unsigned_int)
+ edge_indices[0] = edge_index;
+ else
+ {
+ Assert(edge_indices[1] == numbers::invalid_unsigned_int,
+ ExcInternalError());
+ edge_indices[1] = edge_index;
+ }
+ }
+
+
+ /**
+ * Return an iterator pointing to the first element of the set.
+ */
+ const_iterator
+ begin() const
+ {
+ return edge_indices;
+ }
+
+
+ /**
+ * Return an iterator pointing to the element past the last used one.
+ */
+ const_iterator
+ end() const
+ {
+ // check whether the current object stores zero, one, or two
+ // indices, and use this to point to the element past the
+ // last valid one
+ if (edge_indices[0] == numbers::invalid_unsigned_int)
+ return edge_indices;
+ else if (edge_indices[1] == numbers::invalid_unsigned_int)
+ return edge_indices + 1;
+ else
+ return edge_indices + 2;
+ }
+
+ private:
+ /**
+ * Storage space to store the indices of at most two edges.
+ */
+ unsigned int edge_indices[2];
+ };
+
+
+
+ /**
+ * A class that represents by how much the set of parallel edges
+ * grows in each step. In the graph orientation paper, this set is
+ * called $\Delta_k$, thus the name.
+ *
+ * In 3d, this set can have arbitrarily many elements, unlike the
+ * 2d case specialized above. Consequently, we simply represent
+ * the data structure with a std::set. Class derivation ensures
+ * that we simply inherit all of the member functions of the
+ * base class.
+ */
+ template <>
+ class EdgeDeltaSet<3> : public std::set<unsigned int>
+ {};
+
+
+
+ /**
+ * From a list of cells, build a sorted vector that contains all of the
+ * edges that exist in the mesh.
+ */
+ template <int dim>
+ std::vector<Edge<dim>>
+ build_edges(const std::vector<CellData<dim>> &cells)
+ {
+ // build the edge list for all cells. because each cell has
+ // GeometryInfo<dim>::lines_per_cell edges, the total number
+ // of edges is this many times the number of cells. of course
+ // some of them will be duplicates, and we throw them out below
+ std::vector<Edge<dim>> edge_list;
+ edge_list.reserve(cells.size() * GeometryInfo<dim>::lines_per_cell);
+ for (unsigned int i = 0; i < cells.size(); ++i)
+ for (unsigned int l = 0; l < GeometryInfo<dim>::lines_per_cell; ++l)
+ edge_list.emplace_back(cells[i], l);
+
+ // next sort the edge list and then remove duplicates
+ std::sort(edge_list.begin(), edge_list.end());
+ edge_list.erase(std::unique(edge_list.begin(), edge_list.end()),
+ edge_list.end());
+
+ return edge_list;
+ }
+
+
+
+ /**
+ * Build the cell list. Update the edge array to let edges know
+ * which cells are adjacent to them.
+ */
+ template <int dim>
+ std::vector<Cell<dim>>
+ build_cells_and_connect_edges(const std::vector<CellData<dim>> &cells,
+ std::vector<Edge<dim>> & edges)
+ {
+ std::vector<Cell<dim>> cell_list;
+ cell_list.reserve(cells.size());
+ for (unsigned int i = 0; i < cells.size(); ++i)
+ {
+ // create our own data structure for the cells and let it
+ // connect to the edges array
+ cell_list.emplace_back(cells[i], edges);
+
+ // then also inform the edges that they are adjacent
+ // to the current cell, and where within this cell
+ for (unsigned int l = 0; l < GeometryInfo<dim>::lines_per_cell; ++l)
+ edges[cell_list.back().edge_indices[l]].adjacent_cells.push_back(
+ AdjacentCell(i, l));
+ }
+ Assert(cell_list.size() == cells.size(), ExcInternalError());
+
+ return cell_list;
+ }
+
+
+
+ /**
+ * Return the index within 'cells' of the first cell that has at least one
+ * edge that is not yet oriented.
+ */
+ template <int dim>
+ unsigned int
+ get_next_unoriented_cell(const std::vector<Cell<dim>> &cells,
+ const std::vector<Edge<dim>> &edges,
+ const unsigned int current_cell)
+ {
+ for (unsigned int c = current_cell; c < cells.size(); ++c)
+ for (unsigned int l = 0; l < GeometryInfo<dim>::lines_per_cell; ++l)
+ if (edges[cells[c].edge_indices[l]].orientation_status ==
+ Edge<dim>::not_oriented)
+ return c;
+
+ return numbers::invalid_unsigned_int;
+ }
+
+
+
+ /**
+ * Given a set of cells and edges, orient all edges that are
+ * (global) parallel to the one identified by the @p cell and
+ * within it the one with index @p local_edge.
+ */
+ template <int dim>
+ void
+ orient_one_set_of_parallel_edges(const std::vector<Cell<dim>> &cells,
+ std::vector<Edge<dim>> & edges,
+ const unsigned int cell,
+ const unsigned int local_edge)
+ {
+ // choose the direction of the first edge. we have free choice
+ // here and could simply choose "forward" if that's what pleases
+ // us. however, for backward compatibility with the previous
+ // implementation used till 2016, let us just choose the
+ // direction so that it matches what we have in the given cell.
+ //
+ // in fact, in what can only be assumed to be a bug in the
+ // original implementation, after orienting all edges, the code
+ // that rotates the cells so that they match edge orientations
+ // (see the rotate_cell() function below) rotated the cell two
+ // more times by 90 degrees. this is ok -- it simply flips all
+ // edge orientations, which leaves them valid. rather than do
+ // the same in the current implementation, we can achieve the
+ // same effect by modifying the rule above to choose the
+ // direction of the starting edge of this parallel set
+ // *opposite* to what it looks like in the current cell
+ //
+ // this bug only existed in the 2d implementation since there
+ // were different implementations for 2d and 3d. consequently,
+ // only replicate it for the 2d case and be "intuitive" in 3d.
+ if (edges[cells[cell].edge_indices[local_edge]].vertex_indices[0] ==
+ cells[cell].vertex_indices[GeometryInfo<dim>::line_to_cell_vertices(
+ local_edge, 0)])
+ // orient initial edge *opposite* to the way it is in the cell
+ // (see above for the reason)
+ edges[cells[cell].edge_indices[local_edge]].orientation_status =
+ (dim == 2 ? Edge<dim>::backward : Edge<dim>::forward);
+ else
+ {
+ Assert(
+ edges[cells[cell].edge_indices[local_edge]].vertex_indices[0] ==
+ cells[cell].vertex_indices
+ [GeometryInfo<dim>::line_to_cell_vertices(local_edge, 1)],
+ ExcInternalError());
+ Assert(
+ edges[cells[cell].edge_indices[local_edge]].vertex_indices[1] ==
+ cells[cell].vertex_indices
+ [GeometryInfo<dim>::line_to_cell_vertices(local_edge, 0)],
+ ExcInternalError());
+
+ // orient initial edge *opposite* to the way it is in the cell
+ // (see above for the reason)
+ edges[cells[cell].edge_indices[local_edge]].orientation_status =
+ (dim == 2 ? Edge<dim>::forward : Edge<dim>::backward);
+ }
+
+ // walk outward from the given edge as described in
+ // the algorithm in the paper that documents all of
+ // this
+ //
+ // note that in 2d, each of the Deltas can at most
+ // contain two elements, whereas in 3d it can be arbitrarily many
+ EdgeDeltaSet<dim> Delta_k;
+ EdgeDeltaSet<dim> Delta_k_minus_1;
+ Delta_k_minus_1.insert(cells[cell].edge_indices[local_edge]);
+
+ while (Delta_k_minus_1.begin() !=
+ Delta_k_minus_1.end()) // while set is not empty
+ {
+ Delta_k.clear();
+
+ for (typename EdgeDeltaSet<dim>::const_iterator delta =
+ Delta_k_minus_1.begin();
+ delta != Delta_k_minus_1.end();
+ ++delta)
+ {
+ Assert(edges[*delta].orientation_status !=
+ Edge<dim>::not_oriented,
+ ExcInternalError());
+
+ // now go through the cells adjacent to this edge
+ for (typename AdjacentCells<dim>::const_iterator adjacent_cell =
+ edges[*delta].adjacent_cells.begin();
+ adjacent_cell != edges[*delta].adjacent_cells.end();
+ ++adjacent_cell)
+ {
+ const unsigned int K = adjacent_cell->cell_index;
+ const unsigned int delta_is_edge_in_K =
+ adjacent_cell->edge_within_cell;
+
+ // figure out the direction of delta with respect to the cell
+ // K (in the orientation in which the user has given it to us)
+ const unsigned int first_edge_vertex =
+ (edges[*delta].orientation_status == Edge<dim>::forward ?
+ edges[*delta].vertex_indices[0] :
+ edges[*delta].vertex_indices[1]);
+ const unsigned int first_edge_vertex_in_K =
+ cells[K]
+ .vertex_indices[GeometryInfo<dim>::line_to_cell_vertices(
+ delta_is_edge_in_K, 0)];
+ Assert(
+ first_edge_vertex == first_edge_vertex_in_K ||
+ first_edge_vertex ==
+ cells[K].vertex_indices[GeometryInfo<
+ dim>::line_to_cell_vertices(delta_is_edge_in_K, 1)],
+ ExcInternalError());
+
+ // now figure out which direction the each of the "opposite"
+ // edges needs to be oriented into.
+ for (unsigned int o_e = 0;
+ o_e < ParallelEdges<dim>::n_other_parallel_edges;
+ ++o_e)
+ {
+ // get the index of the opposite edge and select which its
+ // first vertex needs to be based on how the current edge
+ // is oriented in the current cell
+ const unsigned int opposite_edge =
+ cells[K].edge_indices[ParallelEdges<
+ dim>::parallel_edges[delta_is_edge_in_K][o_e]];
+ const unsigned int first_opposite_edge_vertex =
+ cells[K].vertex_indices
+ [GeometryInfo<dim>::line_to_cell_vertices(
+ ParallelEdges<
+ dim>::parallel_edges[delta_is_edge_in_K][o_e],
+ (first_edge_vertex == first_edge_vertex_in_K ? 0 :
+ 1))];
+
+ // then determine the orientation of the edge based on
+ // whether the vertex we want to be the edge's first
+ // vertex is already the first vertex of the edge, or
+ // whether it points in the opposite direction
+ const typename Edge<dim>::OrientationStatus
+ opposite_edge_orientation =
+ (edges[opposite_edge].vertex_indices[0] ==
+ first_opposite_edge_vertex ?
+ Edge<dim>::forward :
+ Edge<dim>::backward);
+
+ // see if the opposite edge (there is only one in 2d) has
+ // already been oriented.
+ if (edges[opposite_edge].orientation_status ==
+ Edge<dim>::not_oriented)
+ {
+ // the opposite edge is not yet oriented. do orient it
+ // and add it to Delta_k
+ edges[opposite_edge].orientation_status =
+ opposite_edge_orientation;
+ Delta_k.insert(opposite_edge);
+ }
+ else
+ {
+ // this opposite edge has already been oriented. it
+ // should be consistent with the current one in 2d,
+ // while in 3d it may in fact be mis-oriented, and in
+ // that case the mesh will not be orientable. indicate
+ // this by throwing an exception that we can catch
+ // further up; this has the advantage that we can
+ // propagate through a couple of functions without
+ // having to do error checking and without modifying
+ // the 'cells' array that the user gave us
+ if (dim == 2)
+ {
+ Assert(edges[opposite_edge].orientation_status ==
+ opposite_edge_orientation,
+ ExcMeshNotOrientable());
+ }
+ else if (dim == 3)
+ {
+ if (edges[opposite_edge].orientation_status !=
+ opposite_edge_orientation)
+ throw ExcMeshNotOrientable();
+ }
+ else
+ Assert(false, ExcNotImplemented());
+ }
+ }
+ }
+ }
+
+ // finally copy the new set to the previous one
+ // (corresponding to increasing 'k' by one in the
+ // algorithm)
+ Delta_k_minus_1 = Delta_k;
+ }
+ }
+
+
+ /**
+ * Given data structures @p cell_list and @p edge_list, where
+ * all edges are already oriented, rotate the cell with
+ * index @p cell_index in such a way that its local coordinate
+ * system matches the ones of the adjacent edges. Store the
+ * rotated order of vertices in <code>raw_cells[cell_index]</code>.
+ */
+ template <int dim>
+ void
+ rotate_cell(const std::vector<Cell<dim>> &cell_list,
+ const std::vector<Edge<dim>> &edge_list,
+ const unsigned int cell_index,
+ std::vector<CellData<dim>> & raw_cells)
+ {
+ // find the first vertex of the cell. this is the vertex where dim edges
+ // originate, so for each of the edges record which the starting vertex is
+ unsigned int starting_vertex_of_edge[GeometryInfo<dim>::lines_per_cell];
+ for (unsigned int e = 0; e < GeometryInfo<dim>::lines_per_cell; ++e)
+ {
+ Assert(edge_list[cell_list[cell_index].edge_indices[e]]
+ .orientation_status != Edge<dim>::not_oriented,
+ ExcInternalError());
+ if (edge_list[cell_list[cell_index].edge_indices[e]]
+ .orientation_status == Edge<dim>::forward)
+ starting_vertex_of_edge[e] =
+ edge_list[cell_list[cell_index].edge_indices[e]]
+ .vertex_indices[0];
+ else
+ starting_vertex_of_edge[e] =
+ edge_list[cell_list[cell_index].edge_indices[e]]
+ .vertex_indices[1];
+ }
+
+ // find the vertex number that appears dim times. this will then be
+ // the vertex at which we want to locate the origin of the cell's
+ // coordinate system (i.e., vertex 0)
+ unsigned int origin_vertex_of_cell = numbers::invalid_unsigned_int;
+ switch (dim)
+ {
+ case 2:
+ {
+ // in 2d, we can simply enumerate the possibilities where the
+ // origin may be located because edges zero and one don't share
+ // any vertices, and the same for edges two and three
+ if ((starting_vertex_of_edge[0] == starting_vertex_of_edge[2]) ||
+ (starting_vertex_of_edge[0] == starting_vertex_of_edge[3]))
+ origin_vertex_of_cell = starting_vertex_of_edge[0];
+ else if ((starting_vertex_of_edge[1] ==
+ starting_vertex_of_edge[2]) ||
+ (starting_vertex_of_edge[1] ==
+ starting_vertex_of_edge[3]))
+ origin_vertex_of_cell = starting_vertex_of_edge[1];
+ else
+ Assert(false, ExcInternalError());
+
+ break;
+ }
+
+ case 3:
+ {
+ // one could probably do something similar in 3d, but that seems
+ // more complicated than one wants to write down. just go
+ // through the list of possible starting vertices and check
+ for (origin_vertex_of_cell = 0;
+ origin_vertex_of_cell < GeometryInfo<dim>::vertices_per_cell;
+ ++origin_vertex_of_cell)
+ if (std::count(starting_vertex_of_edge,
+ starting_vertex_of_edge +
+ GeometryInfo<dim>::lines_per_cell,
+ cell_list[cell_index]
+ .vertex_indices[origin_vertex_of_cell]) == dim)
+ break;
+ Assert(origin_vertex_of_cell <
+ GeometryInfo<dim>::vertices_per_cell,
+ ExcInternalError());
+
+ break;
+ }
+
+ default:
+ Assert(false, ExcNotImplemented());
+ }
+
+ // now rotate raw_cells[cell_index] in such a way that its orientation
+ // matches that of cell_list[cell_index]
+ switch (dim)
+ {
+ case 2:
+ {
+ // in 2d, we can literally rotate the cell until its origin
+ // matches the one that we have determined above should be
+ // the origin vertex
+ //
+ // when doing a rotation, take into account the ordering of
+ // vertices (not in clockwise or counter-clockwise sense)
+ while (raw_cells[cell_index].vertices[0] != origin_vertex_of_cell)
+ {
+ const unsigned int tmp = raw_cells[cell_index].vertices[0];
+ raw_cells[cell_index].vertices[0] =
+ raw_cells[cell_index].vertices[1];
+ raw_cells[cell_index].vertices[1] =
+ raw_cells[cell_index].vertices[3];
+ raw_cells[cell_index].vertices[3] =
+ raw_cells[cell_index].vertices[2];
+ raw_cells[cell_index].vertices[2] = tmp;
+ }
+ break;
+ }
+
+ case 3:
+ {
+ // in 3d, the situation is a bit more complicated. from above, we
+ // now know which vertex is at the origin (because 3 edges
+ // originate from it), but that still leaves 3 possible rotations
+ // of the cube. the important realization is that we can choose
+ // any of them: in all 3 rotations, all edges originate from the
+ // one vertex, and that fixes the directions of all 12 edges in
+ // the cube because these 3 cover all 3 equivalence classes!
+ // consequently, we can select an arbitrary one among the
+ // permutations -- for example the following ones:
+ static const unsigned int cube_permutations[8][8] = {
+ {0, 1, 2, 3, 4, 5, 6, 7},
+ {1, 5, 3, 7, 0, 4, 2, 6},
+ {2, 6, 0, 4, 3, 7, 1, 5},
+ {3, 2, 1, 0, 7, 6, 5, 4},
+ {4, 0, 6, 2, 5, 1, 7, 3},
+ {5, 4, 7, 6, 1, 0, 3, 2},
+ {6, 7, 4, 5, 2, 3, 0, 1},
+ {7, 3, 5, 1, 6, 2, 4, 0}};
+
+ unsigned int
+ temp_vertex_indices[GeometryInfo<dim>::vertices_per_cell];
+ for (const unsigned int v : GeometryInfo<dim>::vertex_indices())
+ temp_vertex_indices[v] =
+ raw_cells[cell_index]
+ .vertices[cube_permutations[origin_vertex_of_cell][v]];
+ for (const unsigned int v : GeometryInfo<dim>::vertex_indices())
+ raw_cells[cell_index].vertices[v] = temp_vertex_indices[v];
+
+ break;
+ }
+
+ default:
+ {
+ Assert(false, ExcNotImplemented());
+ }
+ }
+ }
+
+
+ /**
+ * Given a set of cells, find globally unique edge orientations
+ * and then rotate cells so that the coordinate system of the cell
+ * coincides with the coordinate systems of the adjacent edges.
+ */
+ template <int dim>
+ void
+ reorient(std::vector<CellData<dim>> &cells)
+ {
+ // first build the arrays that connect cells to edges and the other
+ // way around
+ std::vector<Edge<dim>> edge_list = build_edges(cells);
+ std::vector<Cell<dim>> cell_list =
+ build_cells_and_connect_edges(cells, edge_list);
+
+ // then loop over all cells and start orienting parallel edge sets
+ // of cells that still have non-oriented edges
+ unsigned int next_cell_with_unoriented_edge = 0;
+ while ((next_cell_with_unoriented_edge = get_next_unoriented_cell(
+ cell_list, edge_list, next_cell_with_unoriented_edge)) !=
+ numbers::invalid_unsigned_int)
+ {
+ // see which edge sets are still not oriented
+ //
+ // we do not need to look at each edge because if we orient edge
+ // 0, we will end up with edge 1 also oriented (in 2d; in 3d, there
+ // will be 3 other edges that are also oriented). there are only
+ // dim independent sets of edges, so loop over these.
+ //
+ // we need to check whether each one of these starter edges may
+ // already be oriented because the line (sheet) that connects
+ // globally parallel edges may be self-intersecting in the
+ // current cell
+ for (unsigned int l = 0; l < dim; ++l)
+ if (edge_list[cell_list[next_cell_with_unoriented_edge]
+ .edge_indices[ParallelEdges<dim>::starter_edges[l]]]
+ .orientation_status == Edge<dim>::not_oriented)
+ orient_one_set_of_parallel_edges(
+ cell_list,
+ edge_list,
+ next_cell_with_unoriented_edge,
+ ParallelEdges<dim>::starter_edges[l]);
+
+ // ensure that we have really oriented all edges now, not just
+ // the starter edges
+ for (unsigned int l = 0; l < GeometryInfo<dim>::lines_per_cell; ++l)
+ Assert(edge_list[cell_list[next_cell_with_unoriented_edge]
+ .edge_indices[l]]
+ .orientation_status != Edge<dim>::not_oriented,
+ ExcInternalError());
+ }
+
+ // now that we have oriented all edges, we need to rotate cells
+ // so that the edges point in the right direction with the now
+ // rotated coordinate system
+ for (unsigned int c = 0; c < cells.size(); ++c)
+ rotate_cell(cell_list, edge_list, c, cells);
+ }
+
+
+ // overload of the function above for 1d -- there is nothing
+ // to orient in that case
+ void reorient(std::vector<CellData<1>> &)
+ {}
+ } // namespace
+
+ template <int dim>
+ void
+ consistently_order_cells(std::vector<CellData<dim>> &cells)
+ {
+ Assert(cells.size() != 0,
+ ExcMessage(
+ "List of elements to orient must have at least one cell"));
+
+ // there is nothing for us to do in 1d
+ if (dim == 1)
+ return;
+
+ // check if grids are already consistent. if so, do
+ // nothing. if not, then do the reordering
+ if (!is_consistent(cells))
+ try
+ {
+ reorient(cells);
+ }
+ catch (const ExcMeshNotOrientable &)
+ {
+ // the mesh is not orientable. this is acceptable if we are in 3d,
+ // as class Triangulation knows how to handle this, but it is
+ // not in 2d; in that case, re-throw the exception
+ if (dim < 3)
+ throw;
+ }
+ }
+
+
// define some transformations
namespace internal
{
GridTools::delete_unused_vertices(vertices,
cells_to_add,
subcelldata_to_add);
- GridReordering<dim, spacedim>::reorder_cells(cells_to_add, true);
+ GridTools::consistently_order_cells(cells_to_add);
// Save manifolds
auto manifold_ids = tria.get_manifold_ids();
const std::vector<Point<deal_II_space_dimension>> &,
std::vector<CellData<deal_II_dimension>> &);
+# if deal_II_dimension == deal_II_space_dimension
+ template void
+ consistently_order_cells(std::vector<CellData<deal_II_dimension>> &);
+# endif
+
template void
shift<deal_II_dimension>(
const Tensor<1, deal_II_space_dimension> &,
projects / dealii.git / commitdiff