Merge pull request #16806 from drwells/remove-hardcoded-inverse-orien…

…tation

Remove hardcoded inverse orientation

include/deal.II/grid/reference_cell.h

@@ -1877,7 +1877,7 @@ ReferenceCell::face_to_cell_vertices(
   if (get_dimension() == 1)
     Assert(combined_face_orientation ==
              ReferenceCell::default_combined_face_orientation(),
-           ExcMessage("In 1D, all cells must have the default orientation."));
+           ExcMessage("In 1D, all faces must have the default orientation."));
   else
     AssertIndexRange(combined_face_orientation, n_face_orientations(face));
 
@@ -1988,9 +1988,13 @@ ReferenceCell::standard_to_real_face_vertex(
   switch (this->kind)
     {
       case ReferenceCells::Vertex:
-      case ReferenceCells::Line:
         DEAL_II_NOT_IMPLEMENTED();
         break;
+      case ReferenceCells::Line:
+        Assert(face_orientation == default_combined_face_orientation(),
+               ExcMessage(
+                 "In 1D, all faces must have the default orientation."));
+        return vertex;
       case ReferenceCells::Triangle:
       case ReferenceCells::Quadrilateral:
         return line_vertex_permutations[face_orientation][vertex];

source/grid/grid_tools.cc

@@ -4791,32 +4791,6 @@ namespace GridTools
     // 1) determine for each vertex a vertex it coincides with and
     //    put it into a map
     {
-      static const int lookup_table_2d[2][2] =
-        //           flip:
-        {
-          {0, 1}, // false
-          {1, 0}  // true
-        };
-
-      static const int lookup_table_3d[2][2][2][4] =
-        //                   orientation flip  rotation
-        {{{
-            {0, 2, 1, 3}, // false       false false
-            {2, 3, 0, 1}  // false       false true
-          },
-          {
-            {3, 1, 2, 0}, // false       true  false
-            {1, 0, 3, 2}  // false       true  true
-          }},
-         {{
-            {0, 1, 2, 3}, // true        false false
-            {1, 3, 0, 2}  // true        false true
-          },
-          {
-            {3, 2, 1, 0}, // true        true  false
-            {2, 0, 3, 1}  // true        true  true
-          }}};
-
       // loop over all periodic face pairs
       for (const auto &pair : tria.get_periodic_face_map())
         {
@@ -4826,34 +4800,22 @@ namespace GridTools
           const auto face_a = pair.first.first->face(pair.first.second);
           const auto face_b =
             pair.second.first.first->face(pair.second.first.second);
+          const auto reference_cell      = pair.first.first->reference_cell();
+          const auto face_reference_cell = face_a->reference_cell();
           const unsigned char combined_orientation = pair.second.second;
+          const unsigned char inverse_combined_orientation =
+            face_reference_cell.get_inverse_combined_orientation(
+              combined_orientation);
 
           AssertDimension(face_a->n_vertices(), face_b->n_vertices());
 
           // loop over all vertices on face
           for (unsigned int i = 0; i < face_a->n_vertices(); ++i)
             {
-              const auto [face_orientation, face_rotation, face_flip] =
-                ::dealii::internal::split_face_orientation(
-                  combined_orientation);
-
               // find the right local vertex index for the second face
-              unsigned int j = 0;
-              switch (dim)
-                {
-                  case 1:
-                    j = i;
-                    break;
-                  case 2:
-                    j = lookup_table_2d[face_flip][i];
-                    break;
-                  case 3:
-                    j = lookup_table_3d[face_orientation][face_flip]
-                                       [face_rotation][i];
-                    break;
-                  default:
-                    AssertThrow(false, ExcNotImplemented());
-                }
+              const unsigned int j =
+                reference_cell.standard_to_real_face_vertex(
+                  i, pair.first.second, inverse_combined_orientation);
 
               // get vertex indices and store in map
               const auto   vertex_a = face_a->vertex_index(i);

source/grid/tria.cc

@@ -1657,6 +1657,10 @@ namespace
     const FaceIterator face_1 = cell_1->face(n_face_1);
     const FaceIterator face_2 = cell_2->face(n_face_2);
 
+    const unsigned char inverse_orientation =
+      face_1->reference_cell().get_inverse_combined_orientation(orientation);
+
+#ifdef DEBUG
     const auto [face_orientation, face_rotation, face_flip] =
       internal::split_face_orientation(orientation);
 
@@ -1670,6 +1674,7 @@ namespace
            ExcMessage("The supplied orientation "
                       "(face_orientation, face_flip, face_rotation) "
                       "is invalid for 2d"));
+#endif
 
     Assert(face_1 != face_2, ExcMessage("face_1 and face_2 are equal!"));
 
@@ -1727,36 +1732,6 @@ namespace
       }
     else // dim == 2 || dim == 3
       {
-        // A lookup table on how to go through the child cells depending on the
-        // orientation:
-        // see Documentation of GeometryInfo for details
-
-        static const int lookup_table_2d[2][2] =
-          //               orientation:
-          {
-            {1, 0}, // false
-            {0, 1}  // true
-          };
-
-        static const int lookup_table_3d[2][2][2][4] =
-          //                           orientation flip  rotation
-          {{{
-              {0, 2, 1, 3}, // false       false false
-              {2, 3, 0, 1}  // false       false true
-            },
-            {
-              {3, 1, 2, 0}, // false       true  false
-              {1, 0, 3, 2}  // false       true  true
-            }},
-           {{
-              {0, 1, 2, 3}, // true        false false
-              {1, 3, 0, 2}  // true        false true
-            },
-            {
-              {3, 2, 1, 0}, // true        true  false
-              {2, 0, 3, 1}  // true        true  true
-            }}};
-
         if (cell_1->has_children())
           {
             if (cell_2->has_children())
@@ -1771,24 +1746,16 @@ namespace
                            GeometryInfo<dim>::max_children_per_face,
                        ExcNotImplemented());
 
+                const auto reference_cell = cell_1->reference_cell();
+
                 for (unsigned int i = 0;
                      i < GeometryInfo<dim>::max_children_per_face;
                      ++i)
                   {
                     // Lookup the index for the second face
-                    unsigned int j = 0;
-                    switch (dim)
-                      {
-                        case 2:
-                          j = lookup_table_2d[face_orientation][i];
-                          break;
-                        case 3:
-                          j = lookup_table_3d[face_orientation][face_flip]
-                                             [face_rotation][i];
-                          break;
-                        default:
-                          AssertThrow(false, ExcNotImplemented());
-                      }
+                    const unsigned int j =
+                      reference_cell.standard_to_real_face_vertex(
+                        i, n_face_1, inverse_orientation);
 
                     // find subcell ids that belong to the subface indices
                     unsigned int child_cell_1 =