Add to the documentation.

git-svn-id: https://svn.dealii.org/trunk@22967 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/include/deal.II/fe/mapping_q1.h b/deal.II/include/deal.II/fe/mapping_q1.h
index 9372ea6dbd98706ef2c1eb96d20b9935907909a0..796570fb7bbb64fa4f7efcf9a68cff62d11e4c91 100644 (file)
--- a/deal.II/include/deal.II/fe/mapping_q1.h
+++ b/deal.II/include/deal.II/fe/mapping_q1.h
@@ -228,6 +228,20 @@ class MappingQ1 : public Mapping<dim,spacedim>
                                          * boundary forms and normal
                                          * vectors.
                                          *
+                                         * This vector has
+                                         * (dim-1)*GeometryInfo<dim>::faces_per_cell
+                                         * entries. The first
+                                         * GeometryInfo<dim>::faces_per_cell
+                                         * contain the vectors in the first
+                                         * tangential direction for each
+                                         * face; the second set of
+                                         * GeometryInfo<dim>::faces_per_cell
+                                         * entries contain the vectors in the
+                                         * second tangential direction (only
+                                         * in 3d, since there we have 2
+                                         * tangential directions per face),
+                                         * etc.
+                                         *
                                          * Filled once.
                                          */
         std::vector<std::vector<Tensor<1,dim> > > unit_tangentials;