]> https://gitweb.dealii.org/ - dealii-svn.git/commitdiff
Add some reasoning to the documentation of a mesh smoothing flag.
authorbangerth <bangerth@0785d39b-7218-0410-832d-ea1e28bc413d>
Sat, 16 Aug 2008 03:07:50 +0000 (03:07 +0000)
committerbangerth <bangerth@0785d39b-7218-0410-832d-ea1e28bc413d>
Sat, 16 Aug 2008 03:07:50 +0000 (03:07 +0000)
git-svn-id: https://svn.dealii.org/trunk@16573 0785d39b-7218-0410-832d-ea1e28bc413d

deal.II/deal.II/include/grid/tria.h

index 45fcc6da0cff612502bef2a4adf86ae1ba5c191c..90c9960edd0890266fe9b7ce6fc67c486b6a28ad 100644 (file)
@@ -816,6 +816,15 @@ namespace internal
  *     after creation of the triangulation. It follows that active
  *     cells on level 1 may not be coarsenend.
  *
+ *     The main use of this flag is to ensure that each cell has at least one
+ *     neighbor in each coordinate direction (i.e. each cell has at least a
+ *     left or right, and at least an upper or lower neighbor in 2d). This is
+ *     a necessary precondition for some algorihms that compute finite
+ *     differences between cells. The DerivativeApproximation class is one of
+ *     these algorithms that require that a triangulation is coarsest_level_1
+ *     unless all cells already have at least one neighbor in each coordinate
+ *     direction on the coarsest level.
+ *
  *   <li> @p smoothing_on_refinement:
  *     This flag sums up all smoothing algorithms which may be performed upon
  *     refinement by flagging some more cells for refinement.

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