add do_not_produce_unrefined_islands flag, new smoothing option

git-svn-id: https://svn.dealii.org/trunk@2303 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/deal.II/include/grid/tria.h b/deal.II/deal.II/include/grid/tria.h
index 4afca25a99694b428c8f76d476946b8e41309330..c4fa6611ee8ff65e3fd5a35d72fdfbec4297d719 100644 (file)
--- a/deal.II/deal.II/include/grid/tria.h
+++ b/deal.II/deal.II/include/grid/tria.h
@@ -24,11 +24,14 @@ enum MeshSmoothing {
 
       eliminate_refined_inner_islands    = 0x100,
       eliminate_refined_boundary_islands = 0x200,
+      do_not_produce_unrefined_islands   = 0x400,
       
       smoothing_on_refinement            = (limit_level_difference_at_vertices |
                                            eliminate_unrefined_islands),
       smoothing_on_coarsening            = (eliminate_refined_inner_islands |
-                                           eliminate_refined_boundary_islands),
+                                           eliminate_refined_boundary_islands |
+                                           do_not_produce_unrefined_islands),
+      
       maximum_smoothing                  = 0xffff
 };
 
@@ -1016,6 +1019,11 @@ struct TriaNumberCache<3> : public TriaNumberCache<2>
  *     refines the mesh according to a criterion associated with a boundary
  *     integral or if one has rough boundary data.
  *
+ *   \item #do_not_produce_unrefined_islands#:
+ *     This flag prevents the occurence of unrefined islands. In more detail:
+ *     It prohibits the coarsening of a cell if 'most of the neighbors' will
+ *     be refined after the step.
+ *
  *   \item #smoothing_on_refinement#:
  *     This flag sums up all smoothing algorithms which may be performed upon
  *     refinement by flagging some more cells for refinement.