Add GridGenerator::concentric_hyper_shells.

This function generates a grid comprised of (as the name states) concentric
hyper shells, where the shells are (controlled by the skewness parameter)
clustered near the inner boundary.

diff --git a/doc/doxygen/images/concentric_hyper_shells_2d.svg b/doc/doxygen/images/concentric_hyper_shells_2d.svg
new file mode 100644 (file)
index 0000000..ac9383d
--- /dev/null
+++ b/doc/doxygen/images/concentric_hyper_shells_2d.svg
@@ -0,0 +1,737 @@
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diff --git a/doc/news/changes/minor/20180715DavidWells b/doc/news/changes/minor/20180715DavidWells
new file mode 100644 (file)
index 0000000..b589f5e
--- /dev/null
+++ b/doc/news/changes/minor/20180715DavidWells
@@ -0,0 +1,5 @@
+New: A new function GridGenerator::concentric_hyper_shells has been added. This
+function generates a grid comprised of shells of varying widths, where the
+shells near the center are much thinner than those near the outer boundary.
+<br>
+(David Wells, 2018/07/15)

diff --git a/include/deal.II/grid/grid_generator.h b/include/deal.II/grid/grid_generator.h
index e470279f47d149632a1a2e1e96edbef5a959aae2..56da7be5609a6e6eab231d4cedcaac1f7179371b 100644 (file)
--- a/include/deal.II/grid/grid_generator.h
+++ b/include/deal.II/grid/grid_generator.h
@@ -991,6 +991,88 @@ namespace GridGenerator
                                    const unsigned int  repetitions  = 1,
                                    const bool          colorize     = false);
 
+  /**
+   * Produce a grid consisting of concentric shells. The primary difference
+   * between this function and GridGenerator::hyper_shell is that this
+   * function permits unevenly spaced (in the radial direction) coarse level
+   * cells.
+   *
+   * The parameters @p center, @p inner_radius, and @p outer_radius behave in
+   * the same way as the first three arguments to
+   * GridGenerator::hyper_shell. @p n_shells gives the total number of shells
+   * to use (i.e., the number of cells in the radial direction). The outer
+   * radius of the $k$th shell is given by
+   *
+   * @f[
+   *     r = r_{\text{inner}} + (r_\text{outer} - r_\text{inner})
+   *     \frac{1 - \tanh(\text{skewness}(1 - k/\text{n_shells}))}
+   *          {\tanh(\text{skewness})}
+   * @f]
+   *
+   * where @p skewness is a parameter controlling the shell spacing in the
+   * radial direction: values of @p skewness close to zero correspond to even
+   * spacing, while larger values of @p skewness (such as $2$ or $3$)
+   * correspond to shells biased to the inner radius.
+   *
+   * @p n_cells_per_shell is the same as in GridGenerator::hyper_shell: in 2d
+   * the default choice of zero will result in 8 cells per shell (and 12 in
+   * 3d). The only valid values in 3d are 6 (the default), 12, and 96 cells:
+   * see the documentation of GridGenerator::hyper_shell for more information.
+   *
+   * If @p colorize is <code>true</code> then the outer boundary of the merged
+   * shells has a boundary id of $1$ and the inner boundary has a boundary id
+   * of $0$.
+   *
+   * Example: The following code (see, e.g., step-10 for instructions on how
+   * to visualize GNUPLOT output)
+   *
+   * @code
+   * #include <deal.II/fe/mapping_q_generic.h>
+   *
+   * #include <deal.II/grid/grid_generator.h>
+   * #include <deal.II/grid/grid_out.h>
+   * #include <deal.II/grid/tria.h>
+   *
+   * #include <fstream>
+   *
+   * int main()
+   * {
+   *   using namespace dealii;
+   *
+   *   Triangulation<2> triangulation;
+   *   GridGenerator::concentric_hyper_shells(triangulation,
+   *                                          Point<2>(),
+   *                                          1.0,
+   *                                          2.0,
+   *                                          5u,
+   *                                          2.0);
+   *
+   *   GridOut grid_out;
+   *   GridOutFlags::Gnuplot gnuplot_flags(false, 10, true);
+   *   grid_out.set_flags(gnuplot_flags);
+   *
+   *   const MappingQGeneric<2> mapping(3);
+   *   std::ofstream out("out.gpl");
+   *   grid_out.write_gnuplot(triangulation, out, &mapping);
+   * }
+   * @endcode
+   *
+   * generates the following output:
+   *
+   * @image html concentric_hyper_shells_2d.svg
+   *
+   */
+  template <int dim>
+  void
+  concentric_hyper_shells(Triangulation<dim> &triangulation,
+                          const Point<dim> &  center,
+                          const double        inner_radius      = 0.125,
+                          const double        outer_radius      = 0.25,
+                          const unsigned int  n_shells          = 1,
+                          const double        skewness          = 0.1,
+                          const unsigned int  n_cells_per_shell = 0,
+                          const bool          colorize          = false);
+
   /**
    * Produce a ring of cells in 3d that is cut open, twisted and glued
    * together again. This results in a kind of moebius-loop.

diff --git a/source/grid/grid_generator.cc b/source/grid/grid_generator.cc
index 313a3302f00b9d0a9c9ef155b09ded1629f711ed..a05207881cf892a1ed4da8a95a0a5187df288c2b 100644 (file)
--- a/source/grid/grid_generator.cc
+++ b/source/grid/grid_generator.cc
@@ -4701,6 +4701,127 @@ namespace GridGenerator
 
 
 
+  template <int dim>
+  void
+  concentric_hyper_shells(Triangulation<dim> &triangulation,
+                          const Point<dim> &  center,
+                          const double        inner_radius,
+                          const double        outer_radius,
+                          const unsigned int  n_shells,
+                          const double        skewness,
+                          const unsigned int  n_cells,
+                          const bool          colorize)
+  {
+    Assert(dim == 2 || dim == 3, ExcNotImplemented());
+    (void)colorize;
+    (void)n_cells;
+    Assert(inner_radius < outer_radius,
+           ExcMessage("outer_radius has to be bigger than inner_radius."));
+    if (n_shells == 0)
+      return; // empty Triangulation
+
+    std::vector<double> radii;
+    radii.push_back(inner_radius);
+    for (unsigned int shell_n = 1; shell_n < n_shells; ++shell_n)
+      if (skewness == 0.0)
+        // same as below, but works in the limiting case of zero skewness
+        radii.push_back(inner_radius +
+                        (outer_radius - inner_radius) *
+                          (1.0 - (1.0 - double(shell_n) / n_shells)));
+      else
+        radii.push_back(
+          inner_radius +
+          (outer_radius - inner_radius) *
+            (1.0 - std::tanh(skewness * (1.0 - double(shell_n) / n_shells)) /
+                     std::tanh(skewness)));
+    radii.push_back(outer_radius);
+
+    auto min_line_length = [](const Triangulation<dim> &tria) -> double {
+      double length = std::numeric_limits<double>::max();
+      for (const auto cell : tria.active_cell_iterators())
+        for (unsigned int n = 0; n < GeometryInfo<dim>::lines_per_cell; ++n)
+          length = std::min(length, cell->line(n)->diameter());
+      return length;
+    };
+
+    double grid_vertex_tolerance = 0.0;
+    for (unsigned int shell_n = 0; shell_n < radii.size() - 1; ++shell_n)
+      {
+        Triangulation<dim> current_shell;
+        GridGenerator::hyper_shell(current_shell,
+                                   center,
+                                   radii[shell_n],
+                                   radii[shell_n + 1],
+                                   n_cells == 0 ? (dim == 2 ? 8 : 12) :
+                                                  n_cells);
+
+        // The innermost shell has the smallest cells: use that to set the
+        // vertex merging tolerance
+        if (grid_vertex_tolerance == 0.0)
+          grid_vertex_tolerance = 0.5 * min_line_length(current_shell);
+
+        Triangulation<dim> temp(std::move(triangulation));
+        triangulation.clear();
+        GridGenerator::merge_triangulations(current_shell,
+                                            temp,
+                                            triangulation,
+                                            grid_vertex_tolerance);
+      }
+
+    const types::manifold_id manifold_id = 0;
+    triangulation.set_all_manifold_ids(manifold_id);
+    if (dim == 2)
+      triangulation.set_manifold(manifold_id, PolarManifold<dim>(center));
+    else if (dim == 3)
+      triangulation.set_manifold(manifold_id, SphericalManifold<dim>(center));
+
+    // We use boundary vertex positions to see if things are on the inner or
+    // outer boundary.
+    constexpr double radial_vertex_tolerance =
+      100.0 * std::numeric_limits<double>::epsilon();
+    auto assert_vertex_distance_within_tolerance =
+      [center, radial_vertex_tolerance](
+        const TriaIterator<TriaAccessor<dim - 1, dim, dim>> face,
+        const double                                        radius) {
+        (void)face;
+        (void)radius;
+        for (unsigned int vertex_n = 0;
+             vertex_n < GeometryInfo<dim>::vertices_per_face;
+             ++vertex_n)
+          {
+            Assert(std::abs((face->vertex(vertex_n) - center).norm() - radius) <
+                     (center.norm() + radius) * radial_vertex_tolerance,
+                   ExcInternalError());
+          }
+      };
+    if (colorize)
+      for (const auto &cell : triangulation.active_cell_iterators())
+        for (unsigned int face_n = 0;
+             face_n < GeometryInfo<dim>::faces_per_cell;
+             ++face_n)
+          {
+            auto face = cell->face(face_n);
+            if (face->at_boundary())
+              {
+                if (((face->vertex(0) - center).norm() - inner_radius) <
+                    (center.norm() + inner_radius) * radial_vertex_tolerance)
+                  {
+                    // we must be at an inner face, but check
+                    assert_vertex_distance_within_tolerance(face, inner_radius);
+                    face->set_all_boundary_ids(0);
+                  }
+                else
+                  {
+                    // we must be at an outer face, but check
+                    assert_vertex_distance_within_tolerance(face, outer_radius);
+                    face->set_all_boundary_ids(1);
+                  }
+              }
+          }
+  }
+
+
+
   template <>
   void hyper_cube_with_cylindrical_hole(Triangulation<3> & triangulation,
                                         const double       inner_radius,

diff --git a/source/grid/grid_generator.inst.in b/source/grid/grid_generator.inst.in
index b64c8f60a4a8d21f6b045b2fd96db50489da2ebe..6ac4262276c12971676437da5e4dc17b97e63f6f 100644 (file)
--- a/source/grid/grid_generator.inst.in
+++ b/source/grid/grid_generator.inst.in
@@ -183,6 +183,15 @@ for (deal_II_dimension : DIMENSIONS)
         const bool);
 #endif
 
+      template void
+      concentric_hyper_shells(Triangulation<deal_II_dimension> &,
+                              const Point<deal_II_dimension> &,
+                              const double,
+                              const double,
+                              const unsigned int,
+                              const double,
+                              const unsigned int,
+                              const bool);
 
     \}
   }

diff --git a/tests/grid/concentric_hyper_shell_01.cc b/tests/grid/concentric_hyper_shell_01.cc
new file mode 100644 (file)
index 0000000..916298b
--- /dev/null
+++ b/tests/grid/concentric_hyper_shell_01.cc
@@ -0,0 +1,90 @@
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 2018 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.
+//
+// ---------------------------------------------------------------------
+
+#include <deal.II/grid/grid_generator.h>
+#include <deal.II/grid/tria.h>
+
+#include "../tests.h"
+
+// Test GridGenerator::concentric_hyper_shell with skewness = 2.0
+
+int
+main()
+{
+  initlog();
+
+  // 2D test
+  {
+    Triangulation<2> triangulation;
+    const Point<2>   center(0.0, 1.0);
+    GridGenerator::concentric_hyper_shells(
+      triangulation, center, 1.0, 4.0, 3u, 2.0, 4, true);
+
+    for (const auto &cell : triangulation.active_cell_iterators())
+      {
+        deallog << "vertices: " << cell->vertex(0) << ", " << cell->vertex(1)
+                << ", " << cell->vertex(2) << ", " << cell->vertex(3)
+                << std::endl;
+
+        bool manifold_ids_are_zero = cell->manifold_id() == 0;
+        for (unsigned int face_n = 0; face_n < GeometryInfo<2>::faces_per_cell;
+             ++face_n)
+          manifold_ids_are_zero &= cell->face(face_n)->manifold_id() == 0;
+        AssertThrow(manifold_ids_are_zero, ExcInternalError());
+
+        for (unsigned int face_n = 0; face_n < GeometryInfo<2>::faces_per_cell;
+             ++face_n)
+          if (cell->face(face_n)->at_boundary())
+            deallog << "boundary face center distance to origin: "
+                    << (cell->face(face_n)->center(/*respect_manifold*/ true) -
+                        center)
+                         .norm()
+                    << " boundary id: " << cell->face(face_n)->boundary_id()
+                    << std::endl;
+      }
+  }
+
+  // 3D test
+  {
+    Triangulation<3> triangulation;
+    const Point<3>   center(0.0, 1.0, 2.0);
+    GridGenerator::concentric_hyper_shells(
+      triangulation, center, 1.0, 5.0, 2u, 2.0, 0, true);
+
+    for (const auto &cell : triangulation.active_cell_iterators())
+      {
+        deallog << "vertices: " << cell->vertex(0) << ", " << cell->vertex(1)
+                << ", " << cell->vertex(2) << ", " << cell->vertex(3) << ", "
+                << cell->vertex(4) << ", " << cell->vertex(5) << ", "
+                << cell->vertex(6) << ", " << cell->vertex(7) << std::endl;
+
+        bool manifold_ids_are_zero = cell->manifold_id() == 0;
+        for (unsigned int face_n = 0; face_n < GeometryInfo<3>::faces_per_cell;
+             ++face_n)
+          manifold_ids_are_zero &= cell->face(face_n)->manifold_id() == 0;
+        AssertThrow(manifold_ids_are_zero, ExcInternalError());
+
+        for (unsigned int face_n = 0; face_n < GeometryInfo<3>::faces_per_cell;
+             ++face_n)
+          if (cell->face(face_n)->at_boundary())
+            deallog << "boundary face center distance to origin: "
+                    << (cell->face(face_n)->center(/*respect_manifold*/ true) -
+                        center)
+                         .norm()
+                    << " boundary id: " << cell->face(face_n)->boundary_id()
+                    << std::endl;
+      }
+  }
+}

diff --git a/tests/grid/concentric_hyper_shell_01.output b/tests/grid/concentric_hyper_shell_01.output
new file mode 100644 (file)
index 0000000..adc606b
--- /dev/null
+++ b/tests/grid/concentric_hyper_shell_01.output
@@ -0,0 +1,69 @@
+
+DEAL::vertices: 4.00000 1.00000, 2.44929e-16 5.00000, 2.18641 1.00000, 1.33879e-16 3.18641
+DEAL::boundary face center distance to origin: 4.00000 boundary id: 1
+DEAL::vertices: 2.44929e-16 5.00000, -4.00000 1.00000, 1.33879e-16 3.18641, -2.18641 1.00000
+DEAL::boundary face center distance to origin: 4.00000 boundary id: 1
+DEAL::vertices: -4.00000 1.00000, -7.34788e-16 -3.00000, -2.18641 1.00000, -4.01637e-16 -1.18641
+DEAL::boundary face center distance to origin: 4.00000 boundary id: 1
+DEAL::vertices: -7.34788e-16 -3.00000, 4.00000 1.00000, -4.01637e-16 -1.18641, 2.18641 1.00000
+DEAL::boundary face center distance to origin: 4.00000 boundary id: 1
+DEAL::vertices: 2.18641 1.00000, 1.33879e-16 3.18641, 1.29242 1.00000, 7.91377e-17 2.29242
+DEAL::vertices: 1.33879e-16 3.18641, -2.18641 1.00000, 7.91377e-17 2.29242, -1.29242 1.00000
+DEAL::vertices: -2.18641 1.00000, -4.01637e-16 -1.18641, -1.29242 1.00000, -2.37413e-16 -0.292417
+DEAL::vertices: -4.01637e-16 -1.18641, 2.18641 1.00000, -2.37413e-16 -0.292417, 1.29242 1.00000
+DEAL::vertices: 1.29242 1.00000, 7.91377e-17 2.29242, 1.00000 1.00000, 6.12323e-17 2.00000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: 7.91377e-17 2.29242, -1.29242 1.00000, 6.12323e-17 2.00000, -1.00000 1.00000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: -1.29242 1.00000, -2.37413e-16 -0.292417, -1.00000 1.00000, -1.83697e-16 0.00000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: -2.37413e-16 -0.292417, 1.29242 1.00000, -1.83697e-16 0.00000, 1.00000 1.00000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: 0.00000 -0.839949 2.00000, -1.06229 -0.0622949 3.06229, -1.06229 -0.0622949 0.937705, -1.83995 1.00000 2.00000, 0.00000 -4.00000 2.00000, -2.88675 -1.88675 4.88675, -2.88675 -1.88675 -0.886751, -5.00000 1.00000 2.00000
+DEAL::boundary face center distance to origin: 5.00000 boundary id: 1
+DEAL::vertices: -1.06229 -0.0622949 3.06229, 0.00000 1.00000 3.83995, -1.83995 1.00000 2.00000, -1.06229 2.06229 3.06229, -2.88675 -1.88675 4.88675, 0.00000 1.00000 7.00000, -5.00000 1.00000 2.00000, -2.88675 3.88675 4.88675
+DEAL::boundary face center distance to origin: 5.00000 boundary id: 1
+DEAL::vertices: 0.00000 -0.839949 2.00000, 1.06229 -0.0622949 3.06229, -1.06229 -0.0622949 3.06229, 0.00000 1.00000 3.83995, 0.00000 -4.00000 2.00000, 2.88675 -1.88675 4.88675, -2.88675 -1.88675 4.88675, 0.00000 1.00000 7.00000
+DEAL::boundary face center distance to origin: 5.00000 boundary id: 1
+DEAL::vertices: 1.06229 -0.0622949 0.937705, 1.83995 1.00000 2.00000, 0.00000 -0.839949 2.00000, 1.06229 -0.0622949 3.06229, 2.88675 -1.88675 -0.886751, 5.00000 1.00000 2.00000, 0.00000 -4.00000 2.00000, 2.88675 -1.88675 4.88675
+DEAL::boundary face center distance to origin: 5.00000 boundary id: 1
+DEAL::vertices: 1.83995 1.00000 2.00000, 1.06229 2.06229 3.06229, 1.06229 -0.0622949 3.06229, 0.00000 1.00000 3.83995, 5.00000 1.00000 2.00000, 2.88675 3.88675 4.88675, 2.88675 -1.88675 4.88675, 0.00000 1.00000 7.00000
+DEAL::boundary face center distance to origin: 5.00000 boundary id: 1
+DEAL::vertices: 1.06229 2.06229 3.06229, 0.00000 2.83995 2.00000, 0.00000 1.00000 3.83995, -1.06229 2.06229 3.06229, 2.88675 3.88675 4.88675, 0.00000 6.00000 2.00000, 0.00000 1.00000 7.00000, -2.88675 3.88675 4.88675
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+DEAL::vertices: 1.83995 1.00000 2.00000, 1.06229 2.06229 0.937705, 1.06229 2.06229 3.06229, 0.00000 2.83995 2.00000, 5.00000 1.00000 2.00000, 2.88675 3.88675 -0.886751, 2.88675 3.88675 4.88675, 0.00000 6.00000 2.00000
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+DEAL::boundary face center distance to origin: 5.00000 boundary id: 1
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+DEAL::boundary face center distance to origin: 5.00000 boundary id: 1
+DEAL::vertices: 1.06229 -0.0622949 0.937705, 0.00000 -0.839949 2.00000, 0.00000 1.00000 0.160051, -1.06229 -0.0622949 0.937705, 2.88675 -1.88675 -0.886751, 0.00000 -4.00000 2.00000, 0.00000 1.00000 -3.00000, -2.88675 -1.88675 -0.886751
+DEAL::boundary face center distance to origin: 5.00000 boundary id: 1
+DEAL::vertices: 0.00000 0.00000 2.00000, -0.577350 0.422650 2.57735, -0.577350 0.422650 1.42265, -1.00000 1.00000 2.00000, 0.00000 -0.839949 2.00000, -1.06229 -0.0622949 3.06229, -1.06229 -0.0622949 0.937705, -1.83995 1.00000 2.00000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: -0.577350 0.422650 2.57735, 0.00000 1.00000 3.00000, -1.00000 1.00000 2.00000, -0.577350 1.57735 2.57735, -1.06229 -0.0622949 3.06229, 0.00000 1.00000 3.83995, -1.83995 1.00000 2.00000, -1.06229 2.06229 3.06229
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+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: 1.00000 1.00000 2.00000, 0.577350 1.57735 2.57735, 0.577350 0.422650 2.57735, 0.00000 1.00000 3.00000, 1.83995 1.00000 2.00000, 1.06229 2.06229 3.06229, 1.06229 -0.0622949 3.06229, 0.00000 1.00000 3.83995
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+DEAL::vertices: 1.00000 1.00000 2.00000, 0.577350 1.57735 1.42265, 0.577350 1.57735 2.57735, 0.00000 2.00000 2.00000, 1.83995 1.00000 2.00000, 1.06229 2.06229 0.937705, 1.06229 2.06229 3.06229, 0.00000 2.83995 2.00000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: 0.577350 0.422650 1.42265, 0.00000 1.00000 1.00000, 1.00000 1.00000 2.00000, 0.577350 1.57735 1.42265, 1.06229 -0.0622949 0.937705, 0.00000 1.00000 0.160051, 1.83995 1.00000 2.00000, 1.06229 2.06229 0.937705
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+DEAL::vertices: 0.00000 1.00000 1.00000, -0.577350 0.422650 1.42265, -0.577350 1.57735 1.42265, -1.00000 1.00000 2.00000, 0.00000 1.00000 0.160051, -1.06229 -0.0622949 0.937705, -1.06229 2.06229 0.937705, -1.83995 1.00000 2.00000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: 0.577350 0.422650 1.42265, 0.00000 0.00000 2.00000, 0.00000 1.00000 1.00000, -0.577350 0.422650 1.42265, 1.06229 -0.0622949 0.937705, 0.00000 -0.839949 2.00000, 0.00000 1.00000 0.160051, -1.06229 -0.0622949 0.937705
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0

diff --git a/tests/grid/concentric_hyper_shell_02.cc b/tests/grid/concentric_hyper_shell_02.cc
new file mode 100644 (file)
index 0000000..e8d4a70
--- /dev/null
+++ b/tests/grid/concentric_hyper_shell_02.cc
@@ -0,0 +1,88 @@
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 2018 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.
+//
+// ---------------------------------------------------------------------
+
+#include <deal.II/grid/grid_generator.h>
+#include <deal.II/grid/tria.h>
+
+#include "../tests.h"
+
+// Test GridGenerator::concentric_hyper_shell with skewness = 0.0
+
+int
+main()
+{
+  initlog();
+
+  // 2D test
+  {
+    Triangulation<2> triangulation;
+    const Point<2>   center(0.0, 1.0);
+    GridGenerator::concentric_hyper_shells(
+      triangulation, center, 1.0, 4.0, 3u, 0.0, 4, true);
+
+    for (const auto &cell : triangulation.active_cell_iterators())
+      {
+        deallog << "vertices: " << cell->vertex(0) << ", " << cell->vertex(1)
+                << ", " << cell->vertex(2) << ", " << cell->vertex(3)
+                << std::endl;
+
+        bool manifold_ids_are_zero = cell->manifold_id() == 0;
+        for (unsigned int face_n = 0; face_n < GeometryInfo<2>::faces_per_cell;
+             ++face_n)
+          manifold_ids_are_zero &= cell->face(face_n)->manifold_id() == 0;
+        AssertThrow(manifold_ids_are_zero, ExcInternalError());
+
+        for (unsigned int face_n = 0; face_n < GeometryInfo<2>::faces_per_cell;
+             ++face_n)
+          if (cell->face(face_n)->at_boundary())
+            deallog << "boundary face center distance to origin: "
+                    << (cell->face(face_n)->center(true) - center).norm()
+                    << " boundary id: " << cell->face(face_n)->boundary_id()
+                    << std::endl;
+      }
+  }
+
+  // 3D test
+  {
+    Triangulation<3> triangulation;
+    const Point<3>   center(0.0, 1.0, 2.0);
+    GridGenerator::concentric_hyper_shells(
+      triangulation, center, 1.0, 20.0, 2u, 0.0, 0, true);
+
+    for (const auto &cell : triangulation.active_cell_iterators())
+      {
+        deallog << "vertices: " << cell->vertex(0) << ", " << cell->vertex(1)
+                << ", " << cell->vertex(2) << ", " << cell->vertex(3) << ", "
+                << cell->vertex(4) << ", " << cell->vertex(5) << ", "
+                << cell->vertex(6) << ", " << cell->vertex(7) << std::endl;
+
+        bool manifold_ids_are_zero = cell->manifold_id() == 0;
+        for (unsigned int face_n = 0; face_n < GeometryInfo<3>::faces_per_cell;
+             ++face_n)
+          manifold_ids_are_zero &= cell->face(face_n)->manifold_id() == 0;
+        AssertThrow(manifold_ids_are_zero, ExcInternalError());
+
+        for (unsigned int face_n = 0; face_n < GeometryInfo<3>::faces_per_cell;
+             ++face_n)
+          if (cell->face(face_n)->at_boundary())
+            {
+              deallog << "boundary face center distance to origin: "
+                      << (cell->face(face_n)->center(true) - center).norm()
+                      << " boundary id: " << cell->face(face_n)->boundary_id()
+                      << std::endl;
+            }
+      }
+  }
+}

diff --git a/tests/grid/concentric_hyper_shell_02.output b/tests/grid/concentric_hyper_shell_02.output
new file mode 100644 (file)
index 0000000..ac78edd
--- /dev/null
+++ b/tests/grid/concentric_hyper_shell_02.output
@@ -0,0 +1,69 @@
+
+DEAL::vertices: 4.00000 1.00000, 2.44929e-16 5.00000, 3.00000 1.00000, 1.83697e-16 4.00000
+DEAL::boundary face center distance to origin: 4.00000 boundary id: 1
+DEAL::vertices: 2.44929e-16 5.00000, -4.00000 1.00000, 1.83697e-16 4.00000, -3.00000 1.00000
+DEAL::boundary face center distance to origin: 4.00000 boundary id: 1
+DEAL::vertices: -4.00000 1.00000, -7.34788e-16 -3.00000, -3.00000 1.00000, -5.51091e-16 -2.00000
+DEAL::boundary face center distance to origin: 4.00000 boundary id: 1
+DEAL::vertices: -7.34788e-16 -3.00000, 4.00000 1.00000, -5.51091e-16 -2.00000, 3.00000 1.00000
+DEAL::boundary face center distance to origin: 4.00000 boundary id: 1
+DEAL::vertices: 3.00000 1.00000, 1.83697e-16 4.00000, 2.00000 1.00000, 1.22465e-16 3.00000
+DEAL::vertices: 1.83697e-16 4.00000, -3.00000 1.00000, 1.22465e-16 3.00000, -2.00000 1.00000
+DEAL::vertices: -3.00000 1.00000, -5.51091e-16 -2.00000, -2.00000 1.00000, -3.67394e-16 -1.00000
+DEAL::vertices: -5.51091e-16 -2.00000, 3.00000 1.00000, -3.67394e-16 -1.00000, 2.00000 1.00000
+DEAL::vertices: 2.00000 1.00000, 1.22465e-16 3.00000, 1.00000 1.00000, 6.12323e-17 2.00000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: 1.22465e-16 3.00000, -2.00000 1.00000, 6.12323e-17 2.00000, -1.00000 1.00000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: -2.00000 1.00000, -3.67394e-16 -1.00000, -1.00000 1.00000, -1.83697e-16 0.00000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: -3.67394e-16 -1.00000, 2.00000 1.00000, -1.83697e-16 0.00000, 1.00000 1.00000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: 0.00000 -9.50000 2.00000, -6.06218 -5.06218 8.06218, -6.06218 -5.06218 -4.06218, -10.5000 1.00000 2.00000, 0.00000 -19.0000 2.00000, -11.5470 -10.5470 13.5470, -11.5470 -10.5470 -9.54701, -20.0000 1.00000 2.00000
+DEAL::boundary face center distance to origin: 20.0000 boundary id: 1
+DEAL::vertices: -6.06218 -5.06218 8.06218, 0.00000 1.00000 12.5000, -10.5000 1.00000 2.00000, -6.06218 7.06218 8.06218, -11.5470 -10.5470 13.5470, 0.00000 1.00000 22.0000, -20.0000 1.00000 2.00000, -11.5470 12.5470 13.5470
+DEAL::boundary face center distance to origin: 20.0000 boundary id: 1
+DEAL::vertices: 0.00000 -9.50000 2.00000, 6.06218 -5.06218 8.06218, -6.06218 -5.06218 8.06218, 0.00000 1.00000 12.5000, 0.00000 -19.0000 2.00000, 11.5470 -10.5470 13.5470, -11.5470 -10.5470 13.5470, 0.00000 1.00000 22.0000
+DEAL::boundary face center distance to origin: 20.0000 boundary id: 1
+DEAL::vertices: 6.06218 -5.06218 -4.06218, 10.5000 1.00000 2.00000, 0.00000 -9.50000 2.00000, 6.06218 -5.06218 8.06218, 11.5470 -10.5470 -9.54701, 20.0000 1.00000 2.00000, 0.00000 -19.0000 2.00000, 11.5470 -10.5470 13.5470
+DEAL::boundary face center distance to origin: 20.0000 boundary id: 1
+DEAL::vertices: 10.5000 1.00000 2.00000, 6.06218 7.06218 8.06218, 6.06218 -5.06218 8.06218, 0.00000 1.00000 12.5000, 20.0000 1.00000 2.00000, 11.5470 12.5470 13.5470, 11.5470 -10.5470 13.5470, 0.00000 1.00000 22.0000
+DEAL::boundary face center distance to origin: 20.0000 boundary id: 1
+DEAL::vertices: 6.06218 7.06218 8.06218, 0.00000 11.5000 2.00000, 0.00000 1.00000 12.5000, -6.06218 7.06218 8.06218, 11.5470 12.5470 13.5470, 0.00000 21.0000 2.00000, 0.00000 1.00000 22.0000, -11.5470 12.5470 13.5470
+DEAL::boundary face center distance to origin: 20.0000 boundary id: 1
+DEAL::vertices: 10.5000 1.00000 2.00000, 6.06218 7.06218 -4.06218, 6.06218 7.06218 8.06218, 0.00000 11.5000 2.00000, 20.0000 1.00000 2.00000, 11.5470 12.5470 -9.54701, 11.5470 12.5470 13.5470, 0.00000 21.0000 2.00000
+DEAL::boundary face center distance to origin: 20.0000 boundary id: 1
+DEAL::vertices: 6.06218 -5.06218 -4.06218, 0.00000 1.00000 -8.50000, 10.5000 1.00000 2.00000, 6.06218 7.06218 -4.06218, 11.5470 -10.5470 -9.54701, 0.00000 1.00000 -18.0000, 20.0000 1.00000 2.00000, 11.5470 12.5470 -9.54701
+DEAL::boundary face center distance to origin: 20.0000 boundary id: 1
+DEAL::vertices: 0.00000 1.00000 -8.50000, -6.06218 7.06218 -4.06218, 6.06218 7.06218 -4.06218, 0.00000 11.5000 2.00000, 0.00000 1.00000 -18.0000, -11.5470 12.5470 -9.54701, 11.5470 12.5470 -9.54701, 0.00000 21.0000 2.00000
+DEAL::boundary face center distance to origin: 20.0000 boundary id: 1
+DEAL::vertices: -6.06218 7.06218 -4.06218, -10.5000 1.00000 2.00000, 0.00000 11.5000 2.00000, -6.06218 7.06218 8.06218, -11.5470 12.5470 -9.54701, -20.0000 1.00000 2.00000, 0.00000 21.0000 2.00000, -11.5470 12.5470 13.5470
+DEAL::boundary face center distance to origin: 20.0000 boundary id: 1
+DEAL::vertices: 0.00000 1.00000 -8.50000, -6.06218 -5.06218 -4.06218, -6.06218 7.06218 -4.06218, -10.5000 1.00000 2.00000, 0.00000 1.00000 -18.0000, -11.5470 -10.5470 -9.54701, -11.5470 12.5470 -9.54701, -20.0000 1.00000 2.00000
+DEAL::boundary face center distance to origin: 20.0000 boundary id: 1
+DEAL::vertices: 6.06218 -5.06218 -4.06218, 0.00000 -9.50000 2.00000, 0.00000 1.00000 -8.50000, -6.06218 -5.06218 -4.06218, 11.5470 -10.5470 -9.54701, 0.00000 -19.0000 2.00000, 0.00000 1.00000 -18.0000, -11.5470 -10.5470 -9.54701
+DEAL::boundary face center distance to origin: 20.0000 boundary id: 1
+DEAL::vertices: 0.00000 0.00000 2.00000, -0.577350 0.422650 2.57735, -0.577350 0.422650 1.42265, -1.00000 1.00000 2.00000, 0.00000 -9.50000 2.00000, -6.06218 -5.06218 8.06218, -6.06218 -5.06218 -4.06218, -10.5000 1.00000 2.00000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: -0.577350 0.422650 2.57735, 0.00000 1.00000 3.00000, -1.00000 1.00000 2.00000, -0.577350 1.57735 2.57735, -6.06218 -5.06218 8.06218, 0.00000 1.00000 12.5000, -10.5000 1.00000 2.00000, -6.06218 7.06218 8.06218
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: 0.00000 0.00000 2.00000, 0.577350 0.422650 2.57735, -0.577350 0.422650 2.57735, 0.00000 1.00000 3.00000, 0.00000 -9.50000 2.00000, 6.06218 -5.06218 8.06218, -6.06218 -5.06218 8.06218, 0.00000 1.00000 12.5000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: 0.577350 0.422650 1.42265, 1.00000 1.00000 2.00000, 0.00000 0.00000 2.00000, 0.577350 0.422650 2.57735, 6.06218 -5.06218 -4.06218, 10.5000 1.00000 2.00000, 0.00000 -9.50000 2.00000, 6.06218 -5.06218 8.06218
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: 1.00000 1.00000 2.00000, 0.577350 1.57735 2.57735, 0.577350 0.422650 2.57735, 0.00000 1.00000 3.00000, 10.5000 1.00000 2.00000, 6.06218 7.06218 8.06218, 6.06218 -5.06218 8.06218, 0.00000 1.00000 12.5000
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
+DEAL::vertices: 0.577350 1.57735 2.57735, 0.00000 2.00000 2.00000, 0.00000 1.00000 3.00000, -0.577350 1.57735 2.57735, 6.06218 7.06218 8.06218, 0.00000 11.5000 2.00000, 0.00000 1.00000 12.5000, -6.06218 7.06218 8.06218
+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
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+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
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+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
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+DEAL::boundary face center distance to origin: 1.00000 boundary id: 0
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