From: bangerth <bangerth@0785d39b-7218-0410-832d-ea1e28bc413d>
Date: Wed, 17 Dec 2008 01:29:22 +0000 (+0000)
Subject: Properly guard a mutable variable in the MappingQEulerian class.
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d21eb5da6eaf6c62391dc3529d65d02d107ca8e2;p=dealii-svn.git

Properly guard a mutable variable in the MappingQEulerian class.

git-svn-id: https://svn.dealii.org/trunk@17962 0785d39b-7218-0410-832d-ea1e28bc413d
---

diff --git a/deal.II/deal.II/include/fe/mapping_q_eulerian.h b/deal.II/deal.II/include/fe/mapping_q_eulerian.h
index 83a0563262..c5517c31f6 100644
--- a/deal.II/deal.II/include/fe/mapping_q_eulerian.h
+++ b/deal.II/deal.II/include/fe/mapping_q_eulerian.h
@@ -15,6 +15,7 @@
 #define __deal2__mapping_q_eulerian_h
 
 #include <base/smartpointer.h>
+#include <base/thread_management.h>
 #include <grid/tria_iterator.h>
 #include <dofs/dof_handler.h>
 #include <dofs/dof_accessor.h>
@@ -203,6 +204,12 @@ class MappingQEulerian : public MappingQ<dim, spacedim>
                                       */
     mutable FEValues<dim> fe_values;
 
+				     /**
+				      * A variable to guard access to
+				      * the fe_values variable.
+				      */
+    mutable Threads::ThreadMutex fe_values_mutex;
+    
                                      /**
                                       * Compute the positions of the
                                       * support points in the current
diff --git a/deal.II/deal.II/source/fe/mapping_q_eulerian.cc b/deal.II/deal.II/source/fe/mapping_q_eulerian.cc
index 4526338402..f12842a2cf 100644
--- a/deal.II/deal.II/source/fe/mapping_q_eulerian.cc
+++ b/deal.II/deal.II/source/fe/mapping_q_eulerian.cc
@@ -157,9 +157,13 @@ compute_mapping_support_points
 
   std::vector<Vector<double> > shift_vector(n_support_pts,Vector<double>(n_components));
 
-				   // fill shift vector for each support
-				   // point using an fe_values object.
-
+				   // fill shift vector for each
+				   // support point using an fe_values
+				   // object. make sure that the
+				   // fe_values variable isn't used
+				   // simulatenously from different
+				   // threads
+  Threads::ThreadMutex::ScopedLock lock(fe_values_mutex);
   fe_values.reinit(dof_cell);
   fe_values.get_function_values(euler_vector,shift_vector);
 
diff --git a/deal.II/doc/news/changes.h b/deal.II/doc/news/changes.h
index d2d4b0fee1..3481b17471 100644
--- a/deal.II/doc/news/changes.h
+++ b/deal.II/doc/news/changes.h
@@ -598,6 +598,13 @@ inconvenience this causes.
 <h3>deal.II</h3>
 
 <ol>
+  <li>
+  <p>
+  New: The MappingQEulerian function was not thread-safe. This is now fixed.
+  <br>
+  (WB 2008/12/16)
+  </p>
+
   <li>
   <p>
   New: The functions FETools::lexicographic_to_hierarchic_numbering and