Update doc, add changelog item

diff --git a/doc/news/changes/incompatibilities/20171211AlexanderGrayver b/doc/news/changes/incompatibilities/20171211AlexanderGrayver
new file mode 100644 (file)
index 0000000..adfa5ab
--- /dev/null
+++ b/doc/news/changes/incompatibilities/20171211AlexanderGrayver
@@ -0,0 +1,4 @@
+Changed: Change the logic of DoFTools::get_subdomain_association to have the degrees of freedom along a refinement edge be now all given to the processor with the smallest subdomain_id.
+<br>
+(Alexander Grayver, 2017/12/11)
+

diff --git a/include/deal.II/dofs/dof_tools.h b/include/deal.II/dofs/dof_tools.h
index 05d5c29632dde97756b2878e36a4ab707786c488..829cd6b7995d9dd31c04e37486aa08349c14b75e 100644 (file)
--- a/include/deal.II/dofs/dof_tools.h
+++ b/include/deal.II/dofs/dof_tools.h
@@ -1668,13 +1668,13 @@ namespace DoFTools
    *
    * Note that degrees of freedom associated with faces, edges, and vertices
    * may be associated with multiple subdomains if they are sitting on
-   * partition boundaries. In these cases, we put them into one of the
-   * associated partitions in an undefined way. This may sometimes lead to
-   * different numbers of degrees of freedom in partitions, even if the number
-   * of cells is perfectly equidistributed. While this is regrettable, it is
-   * not a problem in practice since the number of degrees of freedom on
-   * partition boundaries is asymptotically vanishing as we refine the mesh as
-   * long as the number of partitions is kept constant.
+   * partition boundaries. In these cases, we assign them to the process with
+   * the smaller subdomain id. This may lead to different numbers of degrees
+   * of freedom in partitions, even if the number of cells is perfectly
+   * equidistributed. While this is regrettable, it is not a problem in
+   * practice since the number of degrees of freedom on partition boundaries
+   * is asymptotically vanishing as we refine the mesh as long as the number
+   * of partitions is kept constant.
    *
    * This function returns the association of each DoF with one subdomain. If
    * you are looking for the association of each @em cell with a subdomain,

diff --git a/source/dofs/dof_tools.cc b/source/dofs/dof_tools.cc
index d58d735a825df50f027c22a29c1397e56977418c..7ad39de9c3b1ace54b008c7fbacb70faf678fb4f 100644 (file)
--- a/source/dofs/dof_tools.cc
+++ b/source/dofs/dof_tools.cc
@@ -1460,7 +1460,7 @@ namespace DoFTools
     local_dof_indices.reserve (max_dofs_per_cell(dof_handler));
 
     // loop over all cells and record which subdomain a DoF belongs to.
-    // toss a coin in case it is on an interface
+    // give to the smaller subdomain_id in case it is on an interface
     typename DoFHandlerType::active_cell_iterator
     cell = dof_handler.begin_active(),
     endc = dof_handler.end();

diff --git a/tests/mpi/blockwise_parallel_01.cc b/tests/mpi/blockwise_parallel_01.cc
new file mode 100644 (file)
index 0000000..73fd956
--- /dev/null
+++ b/tests/mpi/blockwise_parallel_01.cc
@@ -0,0 +1,78 @@
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 2015 - 2017 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 DoFRenumbering::block_wise with parallel::shared::Triangulation
+
+#include "../tests.h"
+
+// all include files you need here
+#include <deal.II/distributed/shared_tria.h>
+#include <deal.II/distributed/tria.h>
+#include <deal.II/grid/grid_generator.h>
+#include <deal.II/fe/fe_q.h>
+#include <deal.II/fe/fe_system.h>
+#include <deal.II/dofs/dof_handler.h>
+#include <deal.II/dofs/dof_tools.h>
+#include <deal.II/dofs/dof_renumbering.h>
+
+template<int dim>
+void test()
+{
+  const unsigned int this_mpi_process =
+      Utilities::MPI::this_mpi_process(MPI_COMM_WORLD);
+
+  FESystem<dim> fe(FE_Q<dim>(1), 2);
+
+  {
+    parallel::shared::Triangulation<dim> tria(MPI_COMM_WORLD, Triangulation<dim>::none, false,
+                                              parallel::shared::Triangulation<dim>::Settings::partition_zorder);
+    GridGenerator::hyper_cube(tria, -1, 1);
+    tria.refine_global(2);
+
+    DoFHandler<dim> dh(tria);
+    dh.distribute_dofs(fe);
+
+    DoFRenumbering::block_wise(dh);
+
+    const std::vector<IndexSet> locally_owned_dofs_per_subdomain =
+        DoFTools::locally_owned_dofs_per_subdomain(dh);
+
+    const types::global_dof_index dofs_per_block = dh.n_dofs() / 2;
+    std::vector<IndexSet> locally_owned_dofs_per_block(2);
+    locally_owned_dofs_per_block[0] =
+        locally_owned_dofs_per_subdomain[this_mpi_process].get_view(0, dofs_per_block);
+    locally_owned_dofs_per_block[1] =
+        locally_owned_dofs_per_subdomain[this_mpi_process].get_view(dofs_per_block, dh.n_dofs());
+
+    // This assertion fails
+    Assert((locally_owned_dofs_per_block[0] == locally_owned_dofs_per_block[1]),
+        ExcMessage("Locally owned dofs differ across blocks."));
+  }
+
+  if (Utilities::MPI::this_mpi_process (MPI_COMM_WORLD) == 0)
+    deallog << "OK for " << dim << "d" << std::endl;
+}
+
+int main (int argc, char* argv[])
+{
+  Utilities::MPI::MPI_InitFinalize mpi_initialization (argc, argv, 1);
+  MPILogInitAll log;
+
+  test<2>();
+  test<3>();
+
+  return 0;
+}
+

diff --git a/tests/mpi/blockwise_parallel_01.mpirun=2.output b/tests/mpi/blockwise_parallel_01.mpirun=2.output
new file mode 100644 (file)
index 0000000..5637e3f
--- /dev/null
+++ b/tests/mpi/blockwise_parallel_01.mpirun=2.output
@@ -0,0 +1,3 @@
+DEAL:0::OK for 2d
+DEAL:0::OK for 3d
+