From 80337a8e142a692efa7fa8026a8cc4d32208da32 Mon Sep 17 00:00:00 2001
From: Timo Heister <timo.heister@gmail.com>
Date: Wed, 6 Jul 2022 17:01:04 -0400
Subject: [PATCH] add test

---
 .../data_out_intermediate_parallel_01.cc      | 93 +++++++++++++++++++
 ...t_intermediate_parallel_01.mpirun=2.output |  6 ++
 2 files changed, 99 insertions(+)
 create mode 100644 tests/data_out/data_out_intermediate_parallel_01.cc
 create mode 100644 tests/data_out/data_out_intermediate_parallel_01.mpirun=2.output

diff --git a/tests/data_out/data_out_intermediate_parallel_01.cc b/tests/data_out/data_out_intermediate_parallel_01.cc
new file mode 100644
index 0000000000..6c3b24674f
--- /dev/null
+++ b/tests/data_out/data_out_intermediate_parallel_01.cc
@@ -0,0 +1,93 @@
+// ---------------------------------------------------------------------
+//
+// 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.
+//
+// ---------------------------------------------------------------------
+
+// Test DataOut::write_deal_II_intermediate_in_parallel()
+
+#include <deal.II/base/mpi.h>
+
+#include <deal.II/dofs/dof_accessor.h>
+#include <deal.II/dofs/dof_handler.h>
+#include <deal.II/dofs/dof_tools.h>
+
+#include <deal.II/fe/fe_q.h>
+
+#include <deal.II/grid/filtered_iterator.h>
+#include <deal.II/grid/grid_generator.h>
+#include <deal.II/grid/tria.h>
+#include <deal.II/grid/tria_iterator.h>
+
+#include <deal.II/lac/vector.h>
+
+#include <deal.II/numerics/data_out.h>
+
+#include "../tests.h"
+
+
+template <int dim>
+void
+check()
+{
+  Triangulation<dim> tria;
+  GridGenerator::hyper_cube(tria, 0., 1.);
+  tria.refine_global(1);
+
+  Vector<double> cell_data(tria.n_active_cells());
+  for (unsigned int i = 0; i < tria.n_active_cells(); ++i)
+    cell_data(i) = i * 1.0;
+
+  FE_Q<dim>       fe(1);
+  DoFHandler<dim> dof_handler(tria);
+  dof_handler.distribute_dofs(fe);
+
+  Vector<double> x(dof_handler.n_dofs());
+
+  DataOut<dim> data_out;
+  data_out.attach_dof_handler(dof_handler);
+  data_out.add_data_vector(cell_data,
+                           "cell_data",
+                           DataOut<dim>::type_cell_data);
+  data_out.add_data_vector(x, "solution");
+
+  data_out.build_patches();
+
+  data_out.write_deal_II_intermediate_in_parallel(
+    "test.d2p", MPI_COMM_WORLD, DataOutBase::VtkFlags::no_compression);
+
+  const unsigned int my_rank =
+    dealii::Utilities::MPI::this_mpi_process(MPI_COMM_WORLD);
+  if (my_rank == 0)
+    {
+      // can't checksum as the file contains "[written by deal.II
+      // 9.5.0-pre]" which would change often, so we just look at the
+      // size for now. This will of course fail once we go to
+      // 10.0. :-)
+      std::ifstream in("test.d2p", std::ifstream::ate | std::ifstream::binary);
+      Assert(in, dealii::ExcIO());
+      deallog << "size: " << in.tellg() << std::endl;
+    }
+
+  deallog << "OK" << std::endl;
+}
+
+int
+main(int argc, char **argv)
+{
+  Utilities::MPI::MPI_InitFinalize mpi_initialization(argc, argv, 1);
+  MPILogInitAll                    all;
+
+  check<2>();
+
+  return 0;
+}
diff --git a/tests/data_out/data_out_intermediate_parallel_01.mpirun=2.output b/tests/data_out/data_out_intermediate_parallel_01.mpirun=2.output
new file mode 100644
index 0000000000..6a193c2262
--- /dev/null
+++ b/tests/data_out/data_out_intermediate_parallel_01.mpirun=2.output
@@ -0,0 +1,6 @@
+
+DEAL:0::size: 1244
+DEAL:0::OK
+
+DEAL:1::OK
+
-- 
2.39.5