Add the testcase from #17599.

diff --git a/tests/lac/constraints_make_consistent_in_parallel_06.cc b/tests/lac/constraints_make_consistent_in_parallel_06.cc
new file mode 100644 (file)
index 0000000..ab168c1
--- /dev/null
+++ b/tests/lac/constraints_make_consistent_in_parallel_06.cc
@@ -0,0 +1,131 @@
+// ------------------------------------------------------------------------
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+// Copyright (C) 2018 - 2023 by the deal.II authors
+//
+// This file is part of the deal.II library.
+//
+// Part of the source code is dual licensed under Apache-2.0 WITH
+// LLVM-exception OR LGPL-2.1-or-later. Detailed license information
+// governing the source code and code contributions can be found in
+// LICENSE.md and CONTRIBUTING.md at the top level directory of deal.II.
+//
+// ------------------------------------------------------------------------
+
+
+
+// test AffineConstraints<double>::make_consistent_in_parallel for case
+// where constraints need to be combined between different ranks
+
+#include <deal.II/distributed/tria.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/hp/fe_collection.h>
+
+#include <deal.II/lac/affine_constraints.h>
+
+#include "../tests.h"
+
+using namespace dealii;
+
+void
+test()
+{
+  static const int dim      = 3;
+  static const int spacedim = 3;
+
+  parallel::distributed::Triangulation<dim, spacedim> triangulation(
+    MPI_COMM_WORLD);
+  DoFHandler<dim, spacedim> dof_handler(triangulation);
+
+  hp::FECollection<dim, spacedim> fe_collection;
+
+  IndexSet locally_active_dofs;
+  IndexSet locally_relevant_dofs;
+
+  std::vector<unsigned int> repetitions({4, 2, 1});
+  Point<dim>                bottom_left(-2, -1, 0);
+  Point<dim>                top_right(2, 1, 1);
+
+  GridGenerator::subdivided_hyper_rectangle(triangulation,
+                                            repetitions,
+                                            bottom_left,
+                                            top_right);
+
+  // hp-refine center part
+  for (const auto &cell : dof_handler.active_cell_iterators() |
+                            IteratorFilters::LocallyOwnedCell())
+    {
+      cell->set_active_fe_index(1);
+
+      const auto &center = cell->center();
+      if (std::abs(center[0]) < 1.)
+        {
+          if (center[1] > 0.)
+            cell->set_active_fe_index(2);
+          else
+            cell->set_refine_flag();
+        }
+    }
+
+  triangulation.execute_coarsening_and_refinement();
+
+  // set dofs
+  for (unsigned int degree = 1; degree <= 10; ++degree)
+    fe_collection.push_back(FE_Q<dim>(degree));
+  dof_handler.distribute_dofs(fe_collection);
+
+  const IndexSet &locally_owned_dofs = dof_handler.locally_owned_dofs();
+  locally_active_dofs   = DoFTools::extract_locally_active_dofs(dof_handler);
+  locally_relevant_dofs = DoFTools::extract_locally_relevant_dofs(dof_handler);
+  AffineConstraints<double> constraints(locally_owned_dofs,
+                                        locally_relevant_dofs);
+
+  const auto show_constraints_63_64 = [&]() {
+    deallog << "What process "
+            << Utilities::MPI::this_mpi_process(MPI_COMM_WORLD)
+            << " believes about DoF 63:" << std::endl;
+    for (const auto &c : constraints.get_lines())
+      if (c.index == 63)
+        for (const auto &entry : c.entries)
+          deallog << "    constrained against " << entry.first
+                  << " with weight " << entry.second << std::endl;
+    deallog << "What process "
+            << Utilities::MPI::this_mpi_process(MPI_COMM_WORLD)
+            << " believes about DoF 64:" << std::endl;
+    for (const auto &c : constraints.get_lines())
+      if (c.index == 64)
+        for (const auto &entry : c.entries)
+          deallog << "    constrained against " << entry.first
+                  << " with weight " << entry.second << std::endl;
+  };
+
+
+  deallog << "------------- make_hanging_node_constraints():" << std::endl;
+  DoFTools::make_hanging_node_constraints(dof_handler, constraints);
+  show_constraints_63_64();
+
+  deallog << "------------- make_consistent_in_parallel():" << std::endl;
+  constraints.make_consistent_in_parallel(locally_owned_dofs,
+                                          locally_relevant_dofs,
+                                          dof_handler.get_communicator());
+  show_constraints_63_64();
+}
+
+
+
+int
+main(int argc, char *argv[])
+{
+  Utilities::MPI::MPI_InitFinalize mpi_init(argc, argv);
+  MPILogInitAll                    all;
+
+  test();
+}

diff --git a/tests/lac/constraints_make_consistent_in_parallel_06.mpirun=2.output b/tests/lac/constraints_make_consistent_in_parallel_06.mpirun=2.output
new file mode 100644 (file)
index 0000000..ef5a5e2
--- /dev/null
+++ b/tests/lac/constraints_make_consistent_in_parallel_06.mpirun=2.output
@@ -0,0 +1,36 @@
+
+DEAL:0::------------- make_hanging_node_constraints():
+DEAL:0::What process 0 believes about DoF 63:
+DEAL:0::    constrained against 3 with weight 0.323607
+DEAL:0::    constrained against 7 with weight -0.123607
+DEAL:0::    constrained against 19 with weight 0.800000
+DEAL:0::What process 0 believes about DoF 64:
+DEAL:0::    constrained against 3 with weight -0.123607
+DEAL:0::    constrained against 7 with weight 0.323607
+DEAL:0::    constrained against 19 with weight 0.800000
+DEAL:0::------------- make_consistent_in_parallel():
+DEAL:0::What process 0 believes about DoF 63:
+DEAL:0::    constrained against 3 with weight 0.323607
+DEAL:0::    constrained against 7 with weight -0.123607
+DEAL:0::    constrained against 19 with weight 0.800000
+DEAL:0::What process 0 believes about DoF 64:
+DEAL:0::    constrained against 3 with weight -0.123607
+DEAL:0::    constrained against 7 with weight 0.323607
+DEAL:0::    constrained against 19 with weight 0.800000
+
+DEAL:1::------------- make_hanging_node_constraints():
+DEAL:1::What process 1 believes about DoF 63:
+DEAL:1::What process 1 believes about DoF 64:
+DEAL:1::    constrained against 3 with weight -0.447214
+DEAL:1::    constrained against 7 with weight 0.447214
+DEAL:1::    constrained against 63 with weight 1.00000
+DEAL:1::------------- make_consistent_in_parallel():
+DEAL:1::What process 1 believes about DoF 63:
+DEAL:1::    constrained against 3 with weight 0.323607
+DEAL:1::    constrained against 7 with weight -0.123607
+DEAL:1::    constrained against 19 with weight 0.800000
+DEAL:1::What process 1 believes about DoF 64:
+DEAL:1::    constrained against 3 with weight -0.123607
+DEAL:1::    constrained against 7 with weight 0.323607
+DEAL:1::    constrained against 19 with weight 0.800000
+