Check whether a function call makes sense at the place where the function is called.

This is instead of returning early in the function. Check that the arguments are indeed
valid within the function.

diff --git a/source/dofs/dof_handler_policy.cc b/source/dofs/dof_handler_policy.cc
index c105f5b648145864701d30a9673dbf6c600199b9..4cd55706a0b1ff1d9e47f247de9d7361bf92c47a 100644 (file)
--- a/source/dofs/dof_handler_policy.cc
+++ b/source/dofs/dof_handler_policy.cc
@@ -537,6 +537,9 @@ namespace internal
                           const unsigned int                                  level,
                           const bool                                          check_validity)
         {
+          Assert (level<dof_handler.get_triangulation().n_levels(),
+                  ExcInternalError());
+
           for (typename std::vector<typename DoFHandler<1,spacedim>::MGVertexDoFs>::iterator
                i=dof_handler.mg_vertex_dofs.begin();
                i!=dof_handler.mg_vertex_dofs.end();
@@ -642,8 +645,8 @@ namespace internal
                           const unsigned int                                  level,
                           const bool                                          check_validity)
         {
-          if (level>=dof_handler.get_triangulation().n_levels())
-            return;
+          Assert (level<dof_handler.get_triangulation().n_levels(),
+                  ExcInternalError());
 
           for (typename std::vector<typename DoFHandler<2,spacedim>::MGVertexDoFs>::iterator i=dof_handler.mg_vertex_dofs.begin();
                i!=dof_handler.mg_vertex_dofs.end(); ++i)
@@ -791,8 +794,9 @@ namespace internal
                           const unsigned int                                  level,
                           const bool                                          check_validity)
         {
-          if (level>=dof_handler.get_triangulation().n_levels())
-            return;
+          Assert (level<dof_handler.get_triangulation().n_levels(),
+                  ExcInternalError());
+
           for (typename std::vector<typename DoFHandler<3,spacedim>::MGVertexDoFs>::iterator i=dof_handler.mg_vertex_dofs.begin();
                i!=dof_handler.mg_vertex_dofs.end(); ++i)
             // if the present vertex lives on the present level
@@ -2268,15 +2272,23 @@ namespace internal
         const unsigned int
         n_cpus = Utilities::MPI::n_mpi_processes (tr->get_communicator());
 
-        unsigned int n_levels = Utilities::MPI::max(dof_handler.get_triangulation().n_levels(), tr->get_communicator());
-
+        // loop over all levels that exist globally (across all
+        // processors), even if the current processor does not in fact
+        // have any cells on that level or if the local part of the
+        // Triangulation has fewer levels. we need to do this because
+        // we need to communicate across all processors on all levels
+        const unsigned int n_levels = Utilities::MPI::max(dof_handler.get_triangulation().n_levels(),
+                                                          tr->get_communicator());
         for (unsigned int level = 0; level < n_levels; ++level)
           {
             NumberCache &number_cache = number_caches[level];
 
             //* 1. distribute on own subdomain
             const unsigned int n_initial_local_dofs =
-              Implementation::distribute_dofs_on_level(0, tr->locally_owned_subdomain(), dof_handler, level);
+              Implementation::distribute_dofs_on_level(0,
+                                                       tr->locally_owned_subdomain(),
+                                                       dof_handler,
+                                                       level);
 
             //* 2. iterate over ghostcells and kill dofs that are not
             // owned by us
@@ -2284,7 +2296,7 @@ namespace internal
             for (dealii::types::global_dof_index i=0; i<renumbering.size(); ++i)
               renumbering[i] = i;
 
-            if (level<tr->n_levels())
+            if (level < tr->n_levels())
               {
                 std::vector<dealii::types::global_dof_index> local_dof_indices;
 
@@ -2345,9 +2357,16 @@ namespace internal
 
             // now re-enumerate all dofs to this shifted and condensed
             // numbering form.  we renumber some dofs as invalid, so
-            // choose the nocheck-version.
-            Implementation::renumber_mg_dofs (renumbering, IndexSet(0),
-                                              dof_handler, level, false);
+            // choose the nocheck-version of the function
+            //
+            // of course there is nothing for us to renumber if the
+            // level we are currently dealing with doesn't even exist
+            // within the current triangulation, so skip renumbering
+            // in that case
+            if (level < tr->n_levels())
+              Implementation::renumber_mg_dofs (renumbering, IndexSet(0),
+                                                dof_handler, level,
+                                                false);
 
             // now a little bit of housekeeping
             number_cache.n_global_dofs