Fix a thinko.

git-svn-id: https://svn.dealii.org/trunk@30076 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/source/grid/tria.cc b/deal.II/source/grid/tria.cc
index 37a764938dcddd02854dcda33a8e24ef40cbfb0e..b12116a191a832d380e579367700dc9bd00c6af1 100644 (file)
--- a/deal.II/source/grid/tria.cc
+++ b/deal.II/source/grid/tria.cc
@@ -12206,8 +12206,9 @@ void Triangulation<dim, spacedim>::execute_coarsening ()
   // deleted (if the latter are on a
   // higher level for example)
   //
-  // cells on level 0 are never coarsened, so we can skip it
-  for (unsigned int level = n_levels()-1; level>=1; --level)
+  // since we delete teh *children* of cells, we only need to start
+  // considering cells on the second highest level, n_levels()-2.
+  for (unsigned int level = n_levels()-2; level>=0; --level)
     for (cell = begin(level); cell!=end(level); ++cell)
       if (cell->user_flag_set())
         // use a separate function,