Fix tria::has_hanging_nodes for anisotropically refined meshes

source/grid/tria.cc

@@ -13979,10 +13979,19 @@ template <int dim, int spacedim>
 bool
 Triangulation<dim, spacedim>::has_hanging_nodes() const
 {
-  for (unsigned int lvl = 0; lvl < n_global_levels() - 1; ++lvl)
-    if (n_active_cells(lvl) != 0)
-      return true;
-
+  if (anisotropic_refinement == false)
+    {
+      for (unsigned int lvl = 0; lvl < n_global_levels() - 1; ++lvl)
+        if (n_active_cells(lvl) != 0)
+          return true;
+    }
+  else
+    {
+      for (const auto &cell : active_cell_iterators())
+        for (const auto &i : cell->face_indices())
+          if (cell->face(i)->has_children())
+            return true;
+    }
   return false;
 }
 

tests/grid/grid_has_hanging_nodes.cc

@@ -0,0 +1,42 @@
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 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.
+//
+// ---------------------------------------------------------------------
+
+// Check that has hanging nodes works correctly for anysotropic refinement
+
+#include <deal.II/grid/grid_generator.h>
+#include <deal.II/grid/tria.h>
+
+#include "../tests.h"
+
+int
+main()
+{
+  initlog();
+  Triangulation<2> tria;
+  GridGenerator::hyper_cube(tria);
+  tria.begin_active()->set_refine_flag(RefinementCase<2>::cut_x);
+  tria.execute_coarsening_and_refinement();
+  tria.begin_active()->set_refine_flag(RefinementCase<2>::cut_x);
+  tria.execute_coarsening_and_refinement();
+
+  if (tria.has_hanging_nodes() == false)
+    {
+      deallog << "OK" << std::endl;
+    }
+  else
+    {
+      deallog << "NOT OK" << std::endl;
+    }
+}

tests/grid/grid_has_hanging_nodes.output

@@ -0,0 +1,2 @@
+
+DEAL::OK