From: Martin Kronbichler <kronbichler@lnm.mw.tum.de>
Date: Tue, 7 Mar 2017 17:24:31 +0000 (+0100)
Subject: Fix a bug in cell similarity detection after GridTools::transform
X-Git-Tag: v8.5.0-rc1~51^2~3
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c48e15138bf1846b54bbba369cfe5f5167a4e735;p=dealii.git

Fix a bug in cell similarity detection after GridTools::transform
---

diff --git a/include/deal.II/grid/grid_tools.h b/include/deal.II/grid/grid_tools.h
index a0feb09058..7b1f2e9369 100644
--- a/include/deal.II/grid/grid_tools.h
+++ b/include/deal.II/grid/grid_tools.h
@@ -1727,6 +1727,9 @@ namespace GridTools
                      + cell->face(face)->vertex(2) + cell->face(face)->vertex(3)) / 4.0;
               }
       }
+
+    // Make sure FEValues notices that the mesh has changed
+    triangulation.signals.post_refinement();
   }
 
 
diff --git a/tests/mappings/mapping_q_generic_cell_cache.cc b/tests/mappings/mapping_q_generic_cell_cache.cc
index 436cdb0847..fe484c80b6 100644
--- a/tests/mappings/mapping_q_generic_cell_cache.cc
+++ b/tests/mappings/mapping_q_generic_cell_cache.cc
@@ -13,7 +13,7 @@
 //
 // ---------------------------------------------------------------------
 
-// Test high order MappingQ on a ChartManifold.
+// Test cell similarity over GridTools::transform (here: scale)
 
 #include "../tests.h"
 
@@ -34,6 +34,12 @@ int main()
 {
   initlog ();
 
+  // there used to be a bug in the cell similarity detection beyond the
+  // GridTools::transform method , but cell similarity is only enabled without
+  // threads. to make sure this test is effective, manually set the thread
+  // limit to 1.
+  MultithreadInfo::set_thread_limit(1);
+
   Triangulation<2> triangulation;
   FE_DGQ<2> fe(0);
   QMidpoint<2> qf_cell;