Make code somewhat cleaner and dimension independent. Document better what

exactly we do.

git-svn-id: https://svn.dealii.org/trunk@23014 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/source/fe/mapping_q1.cc b/deal.II/source/fe/mapping_q1.cc
index 3dee5dbf4e3149f13c9e24fb2dbf9750b8cb5a23..200ed752ac4bbcb54abe237b68e7f64ca9a86316 100644 (file)
--- a/deal.II/source/fe/mapping_q1.cc
+++ b/deal.II/source/fe/mapping_q1.cc
@@ -804,59 +804,45 @@ MappingQ1<dim,spacedim>::fill_fe_values (
                  }
                else
                  {
+                   data.contravariant[point]=transpose(data.contravariant[point]);
+
+                                                    // compute the normal
+                                                    // vector to this cell
+                                                    // and put it into the
+                                                    // last row of
+                                                    // data.contravariant
                    if ( (dim==1) && (spacedim==2) )
-                     {
-                       data.contravariant[point] = transpose(data.contravariant[point]);
-                       JxW_values[point]
-                         = data.contravariant[point][0].norm()*weights[point];
-                       if (update_flags & update_normal_vectors)
-                         {
-                           normal_vectors[point][0]
-                             = -(data.contravariant[point][0][1]
-                                 /
-                                 data.contravariant[point][0].norm());
-                           normal_vectors[point][1]
-                             = (data.contravariant[point][0][0]
-                                /
-                                data.contravariant[point][0].norm());
-
-                           if (cell->direction_flag() == false)
-                             normal_vectors[point] *= -1.;
-                         }
-                     }
+                     cross_product(data.contravariant[point][1],
+                                   -data.contravariant[point][0]);
+                   else if ( (dim==2) && (spacedim==3) )
+                     cross_product(data.contravariant[point][2],
+                                   data.contravariant[point][0],
+                                   data.contravariant[point][1]);
                    else
+                     Assert (false, ExcNotImplemented());
+
+                                                    // det(J) is now the norm
+                                                    // of the cross product
+                                                    // of all the mapped unit
+                                                    // tangential vectors
+                   JxW_values[point]
+                     = data.contravariant[point][spacedim-1].norm()*weights[point];
+
+                                                    // in order to compute
+                                                    // the normal vector,
+                                                    // normalize the cross
+                                                    // product of mapped unit
+                                                    // vectors
+                   data.contravariant[point][spacedim-1]
+                     /= data.contravariant[point][spacedim-1].norm();
+                   
+                   if (update_flags & update_normal_vectors)
                      {
-                       if ( (dim==2) && (spacedim==3) )
-                         {
-                           data.contravariant[point]=transpose(data.contravariant[point]);
-                           cross_product(data.contravariant[point][2],
-                                         data.contravariant[point][0],
-                                         data.contravariant[point][1]);
-                           JxW_values[point]
-                             = data.contravariant[point][2].norm()*weights[point];
-
-                                                            // the cell
-                                                            // normal
-                                                            // vector
-                                                            // (normal
-                                                            // to the
-                                                            // surface)
-                                                            // is
-                                                            // stored
-                                                            // in the
-                                                            // 3d
-                                                            // subtensor
-                                                            // of the
-                                                            // contravariant
-                                                            // tensor
-                           data.contravariant[point][2] /= data.contravariant[point][2].norm();
-                           if (update_flags & update_normal_vectors)
-                             {
-                               normal_vectors[point]=data.contravariant[point][2];
-                               if (cell->direction_flag() == false)
-                                 normal_vectors[point] *= -1.;
-                             }
-                         }
+                       normal_vectors[point]
+                         = data.contravariant[point][spacedim-1];
+                       
+                       if (cell->direction_flag() == false)
+                         normal_vectors[point] *= -1.;
                      }
                  }
              }