From d7ca2085406481fff495f5b135a4dc3c254540f1 Mon Sep 17 00:00:00 2001
From: Martin Kronbichler <kronbichler@lnm.mw.tum.de>
Date: Mon, 23 Oct 2017 15:39:15 +0200
Subject: [PATCH] Make sure to actually zero the ghost entries in partitioner
 import call.

---
 include/deal.II/base/partitioner.templates.h |  4 +---
 tests/mpi/parallel_partitioner_07.cc         | 11 +++++++++++
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/include/deal.II/base/partitioner.templates.h b/include/deal.II/base/partitioner.templates.h
index 0b0a45e567..4ffc40f468 100644
--- a/include/deal.II/base/partitioner.templates.h
+++ b/include/deal.II/base/partitioner.templates.h
@@ -402,9 +402,7 @@ namespace Utilities
 
       // clear the ghost array in case we did not yet do that in the _start
       // function
-      if (n_ghost_indices_in_larger_set == n_ghost_indices() ||
-          ghost_array.size() != n_ghost_indices_in_larger_set)
-        std::memset(ghost_array.begin(), 0, sizeof(Number)*n_ghost_indices());
+      std::memset(ghost_array.begin(), 0, sizeof(Number)*n_ghost_indices());
 
       // clear the compress requests
       requests.resize(0);
diff --git a/tests/mpi/parallel_partitioner_07.cc b/tests/mpi/parallel_partitioner_07.cc
index f669b8663c..a78aaa6533 100644
--- a/tests/mpi/parallel_partitioner_07.cc
+++ b/tests/mpi/parallel_partitioner_07.cc
@@ -97,6 +97,9 @@ void test ()
                                            temp_array.size()),
                                        make_array_view(locally_owned_array),
                                        make_array_view(ghosts), requests);
+    // check that the ghost entries are zeroed out in these calls
+    for (unsigned int i=0; i<v.n_ghost_indices(); ++i)
+      AssertDimension(ghosts[i], 0);
   }
   deallog << "From all ghosts: ";
   for (unsigned int i=0; i<locally_owned_array.size(); ++i)
@@ -117,6 +120,10 @@ void test ()
                                            temp_array.size()),
                                        make_array_view(locally_owned_array),
                                        make_array_view(ghosts), requests);
+
+    // check that the ghost entries are zeroed out in these calls
+    for (unsigned int i=0; i<w.n_ghost_indices(); ++i)
+      AssertDimension(ghosts[i], 0);
   }
   deallog << "From reduced ghosts 1: ";
   for (unsigned int i=0; i<locally_owned_array.size(); ++i)
@@ -137,6 +144,10 @@ void test ()
                                            temp_array.size()),
                                        make_array_view(locally_owned_array),
                                        make_array_view(ghosts), requests);
+
+    // check that the ghost entries are zeroed out in these calls
+    for (unsigned int i=0; i<x.n_ghost_indices(); ++i)
+      AssertDimension(ghosts[i], 0);
   }
   deallog << "From reduced ghosts 2: ";
   for (unsigned int i=0; i<locally_owned_array.size(); ++i)
-- 
2.39.5