Fix quadratic complexity inside p::d::Tria::fill_vertices_with_ghost_neighbors

diff --git a/doc/news/changes.h b/doc/news/changes.h
index e8afbbf7ea2cb7103bea88ca00e43e1ff6585eb3..506d671b47e63d8257bd13c57cdef2be263c1698 100644 (file)
--- a/doc/news/changes.h
+++ b/doc/news/changes.h
@@ -451,6 +451,16 @@ inconvenience this causes.
 
 
 <ol>
+  <li> Improved: The method
+  parallel::distributed::Triangulation::fill_vertices_with_ghost_neighbors
+  that is used for distributing DoFs on parallel triangulations previously
+  exhibited quadratic complexity in the number of coarse grid cells. This has
+  been changed into linear complexity calls (apart from a few issues
+  inside p4est).
+  <br>
+  (Martin Kronbichler, 2015/12/05)
+  </li>
+
   <li> Fixed: The constructor of SymmetricTensor that takes an array
   of initializing elements led to a compiler error. This is now
   fixed.

diff --git a/source/distributed/tria.cc b/source/distributed/tria.cc
index c05b7dd64c5d8f460cd425b7af9a0b53f03bc04a..160f40ea625863aca62284cec8a9668325dd98cb 100644 (file)
--- a/source/distributed/tria.cc
+++ b/source/distributed/tria.cc
@@ -4810,8 +4810,8 @@ namespace parallel
     {
       int i, l = quad.level;
       int child_id;
-      const std::vector<types::global_dof_index> perm = triangulation->get_p4est_tree_to_coarse_cell_permutation ();
-      types::global_dof_index dealii_index = perm[treeidx];
+      types::global_dof_index dealii_index =
+        triangulation->get_p4est_tree_to_coarse_cell_permutation()[treeidx];
 
       for (i = 0; i < l; i++)
         {