--- /dev/null
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 2001 - 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.
+//
+// ---------------------------------------------------------------------
+
+#include <deal.II/base/exceptions.h>
+#include <deal.II/base/mpi.h>
+#include <deal.II/base/point.h>
+#include <deal.II/distributed/shared_tria.h>
+#include <deal.II/distributed/tria.h>
+#include <deal.II/grid/grid_generator.h>
+#include <deal.II/grid/grid_tools.h>
+#include <deal.II/grid/tria.h>
+
+#include <vector>
+using namespace dealii;
+template <int dim>
+void test(MPI_Comm comm) {
+ deallog << "dim = " << dim << std::endl;
+ parallel::shared::Triangulation<dim> tria(comm);
+
+ std::vector<typename GridTools::PeriodicFacePair<
+ typename parallel::shared::Triangulation<dim>::cell_iterator>>
+ matched_pairs;
+
+ unsigned int num_refinements = 1 << 4;
+
+ if constexpr (dim == 1) {
+ Point<dim> p1{0.};
+ Point<dim> p2{1.};
+ std::vector<unsigned int> repitions{num_refinements};
+ GridGenerator::subdivided_hyper_rectangle(tria, repitions, p1, p2, true);
+
+ // Collect periodic faces in the x-direction
+ GridTools::collect_periodic_faces(tria, 0, 1, 0, matched_pairs);
+ // Check the size of the matched_pairs vector
+ if (matched_pairs.size() != 1) {
+ // throw error
+ }
+ } else if constexpr (dim == 2) {
+ Point<dim> p1{0., 0.};
+ Point<dim> p2{1., 1.};
+ std::vector<unsigned int> repitions{num_refinements, num_refinements};
+ GridGenerator::subdivided_hyper_rectangle(tria, repitions, p1, p2, true);
+
+ GridTools::collect_periodic_faces(tria, 0, 1, 0, matched_pairs);
+ if (matched_pairs.size() != 16) {
+ }
+ } else if constexpr (dim == 3) {
+ Point<dim> p1{0., 0., 0.};
+ Point<dim> p2{1., 1., 1.};
+ std::vector<unsigned int> repitions{num_refinements, num_refinements,
+ num_refinements};
+ GridGenerator::subdivided_hyper_rectangle(tria, repitions, p1, p2, true);
+
+ GridTools::collect_periodic_faces(tria, 0, 1, 0, matched_pairs);
+ if (matched_pairs.size() != 256) {
+ }
+ }
+}
+
+int main(int argc, char *argv[]) {
+ Utilities::MPI::MPI_InitFinalize mpi_initialization(argc, argv, 1);
+ // mpi_initlog();
+ MPI_Comm comm = MPI_COMM_WORLD;
+ test<1>(comm);
+ test<2>(comm);
+ test<3>(comm);
+
+ return 0;
+}