From 56af65609bca2e7b3e46c66e8b6da29f08d26701 Mon Sep 17 00:00:00 2001
From: Marc Fehling <mafehling.git@gmail.com>
Date: Thu, 9 Feb 2023 13:23:30 -0700
Subject: [PATCH] Added test for SolutionTransfer with hp-refinement and
 manually set flags.

---
 tests/mpi/solution_transfer_11.cc             | 146 ++++++++++++++++++
 .../mpi/solution_transfer_11.mpirun=2.output  |   7 +
 2 files changed, 153 insertions(+)
 create mode 100644 tests/mpi/solution_transfer_11.cc
 create mode 100644 tests/mpi/solution_transfer_11.mpirun=2.output

diff --git a/tests/mpi/solution_transfer_11.cc b/tests/mpi/solution_transfer_11.cc
new file mode 100644
index 0000000000..918cf8e09c
--- /dev/null
+++ b/tests/mpi/solution_transfer_11.cc
@@ -0,0 +1,146 @@
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 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 at
+// the top level of the deal.II distribution.
+//
+// ---------------------------------------------------------------------
+
+
+
+// Test distributed SolutionTransfer with hp-refinement and manually set flags.
+
+
+#include <deal.II/distributed/solution_transfer.h>
+#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/grid_generator.h>
+
+#include <deal.II/hp/fe_collection.h>
+
+#include <deal.II/lac/la_parallel_vector.h>
+
+#include "../tests.h"
+
+
+template <int dim>
+void
+test()
+{
+  parallel::distributed::Triangulation<dim> tria(MPI_COMM_WORLD);
+  GridGenerator::subdivided_hyper_cube(tria, 2);
+  tria.refine_global(1);
+
+  hp::FECollection<dim> fes;
+  for (unsigned int d = 1; d <= 3; ++d)
+    fes.push_back(FE_Q<dim>(d));
+
+  DoFHandler<dim> dofh(tria);
+  for (const auto &cell : dofh.active_cell_iterators())
+    if (cell->is_locally_owned())
+      cell->set_active_fe_index(1);
+
+  dofh.distribute_dofs(fes);
+  IndexSet locally_owned_dofs = dofh.locally_owned_dofs();
+  IndexSet locally_relevant_dofs =
+    DoFTools::extract_locally_relevant_dofs(dofh);
+
+  // set up solution
+  LinearAlgebra::distributed::Vector<double> solution;
+  solution.reinit(locally_owned_dofs,
+                  locally_relevant_dofs,
+                  dofh.get_communicator());
+
+  for (unsigned int i = 0; i < solution.size(); ++i)
+    if (locally_owned_dofs.is_element(i))
+      solution(i) = i;
+  solution.update_ghost_values();
+
+  double l1_norm = solution.l1_norm();
+  if (Utilities::MPI::this_mpi_process(dofh.get_communicator()) == 0)
+    deallog << "pre  refinement l1=" << l1_norm << std::endl;
+
+  // set refine/coarsen flags manually
+  for (const auto &cell : dofh.active_cell_iterators())
+    if (cell->is_locally_owned())
+      {
+        const std::string parent_id_string = cell->parent()->id().to_string();
+
+        if (parent_id_string == "0_0:")
+          {
+            // parent 0: h refinement
+            cell->set_refine_flag();
+          }
+        else if (parent_id_string == "1_0:")
+          {
+            // parent 1: h coarsening
+            cell->set_coarsen_flag();
+          }
+        else if (parent_id_string == "2_0:")
+          {
+            // parent 2: p refinement
+            const auto super_fe_index =
+              fes.next_in_hierarchy(cell->active_fe_index());
+            cell->set_future_fe_index(super_fe_index);
+          }
+        else if (parent_id_string == "3_0:")
+          {
+            // parent 3: p coarsening
+            const auto sub_fe_index =
+              fes.previous_in_hierarchy(cell->active_fe_index());
+            cell->set_future_fe_index(sub_fe_index);
+          }
+        else
+          {
+            Assert(false, ExcInternalError());
+          }
+      }
+
+  // initiate refinement and transfer
+  parallel::distributed::
+    SolutionTransfer<dim, LinearAlgebra::distributed::Vector<double>>
+      soltrans(dofh);
+  soltrans.prepare_for_coarsening_and_refinement(solution);
+
+  tria.execute_coarsening_and_refinement();
+
+  dofh.distribute_dofs(fes);
+  locally_owned_dofs    = dofh.locally_owned_dofs();
+  locally_relevant_dofs = DoFTools::extract_locally_relevant_dofs(dofh);
+
+  solution.reinit(locally_owned_dofs,
+                  locally_relevant_dofs,
+                  dofh.get_communicator());
+  soltrans.interpolate(solution);
+
+  l1_norm = solution.l1_norm();
+  if (Utilities::MPI::this_mpi_process(dofh.get_communicator()) == 0)
+    deallog << "post refinement l1=" << l1_norm << std::endl;
+
+  // make sure no processor is hanging
+  MPI_Barrier(MPI_COMM_WORLD);
+
+  deallog << "OK" << std::endl;
+}
+
+
+int
+main(int argc, char **argv)
+{
+  Utilities::MPI::MPI_InitFinalize mpi_initialization(argc, argv, 1);
+  MPILogInitAll                    log;
+
+  test<2>();
+}
diff --git a/tests/mpi/solution_transfer_11.mpirun=2.output b/tests/mpi/solution_transfer_11.mpirun=2.output
new file mode 100644
index 0000000000..bbd33225f3
--- /dev/null
+++ b/tests/mpi/solution_transfer_11.mpirun=2.output
@@ -0,0 +1,7 @@
+
+DEAL:0::pre  refinement l1=3240.00
+DEAL:0::post refinement l1=4390.76
+DEAL:0::OK
+
+DEAL:1::OK
+
-- 
2.39.5