From c17b95334f838c218765f93ba86d2d3bf57b120b Mon Sep 17 00:00:00 2001
From: David Wells <drwells@email.unc.edu>
Date: Thu, 8 Jun 2023 15:54:48 -0400
Subject: [PATCH] find_active_cell_around_point(): add a simplex test.

---
 .../find_active_cell_around_point_01.cc       | 87 +++++++++++++++++++
 .../find_active_cell_around_point_01.output   |  7 ++
 2 files changed, 94 insertions(+)
 create mode 100644 tests/simplex/find_active_cell_around_point_01.cc
 create mode 100644 tests/simplex/find_active_cell_around_point_01.output

diff --git a/tests/simplex/find_active_cell_around_point_01.cc b/tests/simplex/find_active_cell_around_point_01.cc
new file mode 100644
index 0000000000..82c2bdf668
--- /dev/null
+++ b/tests/simplex/find_active_cell_around_point_01.cc
@@ -0,0 +1,87 @@
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 2017 - 2023 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.
+//
+// ---------------------------------------------------------------------
+
+
+/*
+ * Like grid/find_active_cell_around_point_01, but for simplices.
+ */
+#include <deal.II/base/logstream.h>
+#include <deal.II/base/utilities.h>
+
+#include <deal.II/fe/fe_values.h>
+#include <deal.II/fe/mapping_q1.h>
+
+#include <deal.II/grid/grid_generator.h>
+#include <deal.II/grid/grid_tools.h>
+
+#include <deal.II/hp/fe_collection.h>
+#include <deal.II/hp/fe_values.h>
+#include <deal.II/hp/mapping_collection.h>
+#include <deal.II/hp/q_collection.h>
+
+#include <deal.II/lac/vector.h>
+
+#include <deal.II/numerics/fe_field_function.h>
+#include <deal.II/numerics/vector_tools.h>
+
+#include "../tests.h"
+
+
+template <int dim, int spacedim>
+void
+test(unsigned int n_ref, unsigned int n_points)
+{
+  deallog << "Testing " << dim << ", " << spacedim << std::endl;
+
+  Triangulation<dim, spacedim> tria;
+  GridGenerator::subdivided_hyper_cube_with_simplices(tria, 1);
+  tria.refine_global(n_ref);
+  DoFHandler<dim, spacedim> dof_handler(tria);
+
+  std::vector<Point<spacedim>> points;
+
+  deallog << "Points in study: " << n_points << std::endl;
+  for (std::size_t i = 0; i < n_points; ++i)
+    points.push_back(random_point<spacedim>());
+
+  auto v_to_c   = GridTools::vertex_to_cell_map(tria);
+  auto v_to_c_d = GridTools::vertex_to_cell_centers_directions(tria, v_to_c);
+
+  auto &mapping = tria.get_reference_cells()
+                    .front()
+                    .template get_default_linear_mapping<dim, spacedim>();
+  auto cell = tria.begin_active();
+  for (auto &p : points)
+    {
+      auto c_and_p = GridTools::find_active_cell_around_point(
+        mapping, tria, p, v_to_c, v_to_c_d);
+      auto p2 =
+        mapping.transform_unit_to_real_cell(c_and_p.first, c_and_p.second);
+      if (p2.distance(p) > 1e-10)
+        deallog << "NOT OK!" << p << ", " << p2 << ", " << c_and_p.first
+                << std::endl;
+      cell = c_and_p.first;
+    }
+  deallog << "OK" << std::endl;
+}
+
+int
+main()
+{
+  initlog();
+
+  test<2, 2>(3, 20);
+  test<3, 3>(2, 30);
+}
diff --git a/tests/simplex/find_active_cell_around_point_01.output b/tests/simplex/find_active_cell_around_point_01.output
new file mode 100644
index 0000000000..02d33f830e
--- /dev/null
+++ b/tests/simplex/find_active_cell_around_point_01.output
@@ -0,0 +1,7 @@
+
+DEAL::Testing 2, 2
+DEAL::Points in study: 20
+DEAL::OK
+DEAL::Testing 3, 3
+DEAL::Points in study: 30
+DEAL::OK
-- 
2.39.5