New DoFAccessor test added for vertex dofs

tests/dofs/dof_accessor_02.cc

@@ -0,0 +1,50 @@
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 2010 - 2022 by the deal.II authors
+//
+// This file is part of the deal.II library.
+//
+// The deal.II library is free software; you can use it, redistribute
+// it, and/or modify it under the terms of the GNU Lesser General
+// Public License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+// The full text of the license can be found in the file LICENSE.md at
+// the top level directory of deal.II.
+//
+// ---------------------------------------------------------------------
+
+// Initialize a DOFAccessor for a vertex iterators and then read the
+// dofs of the vertices.
+
+#include <deal.II/dofs/dof_accessor.h>
+#include <deal.II/dofs/dof_handler.h>
+
+#include <deal.II/fe/fe_q.h>
+#include <deal.II/fe/fe_system.h>
+
+#include <deal.II/grid/grid_generator.h>
+#include <deal.II/grid/tria.h>
+
+#include "../tests.h"
+
+int
+main()
+{
+  Triangulation<2> triangulation;
+  GridGenerator::hyper_cube(triangulation);
+  DoFHandler<2>     dof_handler(triangulation);
+  const FESystem<2> finite_element(FE_Q<2>(1), 2);
+  dof_handler.distribute_dofs(finite_element);
+  const auto vertex_end = triangulation.end_vertex();
+  for (auto vertex = triangulation.begin_active_vertex(); vertex != vertex_end;
+       ++vertex)
+    {
+      DoFAccessor<0, 2, 2, false> vertex_dofs(&triangulation,
+                                              vertex->level(),
+                                              vertex->index(),
+                                              &dof_handler);
+      deallog << vertex_dofs.dof_index(0) << ", " << vertex_dofs.dof_index(1)
+              << std::endl;
+    }
+  return 0;
+}

tests/dofs/dof_accessor_02.output

@@ -0,0 +1,4 @@
+0, 1
+2, 3
+4, 5
+6, 7