Use a cheaper call.

The functions in question take an IndexSet argument that can either mean
something, or if it is empty, is ignored. In the places where an empty
IndexSet is passed, it actually has size zero, not just zero elements,
but in the existing code, we test whether 'indices.n_elements()==0'.
It turns out that 'n_elements()' is a pretty expensive function to call.
What we really wanted, of course, was 'indices.size()==0', and this
patch makes that change.

I ran all multigrid tests (the functions in question are multigrid
related), and they all succeed.

diff --git a/source/dofs/dof_handler_policy.cc b/source/dofs/dof_handler_policy.cc
index 8bf34a09189fb73c1cda19b6fbc3cafe002e091d..704486901dcd5338653fd27b45ea2935a6c73a1e 100644 (file)
--- a/source/dofs/dof_handler_policy.cc
+++ b/source/dofs/dof_handler_policy.cc
@@ -561,7 +561,7 @@ namespace internal
 
                   if (idx != DoFHandler<1>::invalid_dof_index)
                     i->set_index (level, d,
-                                  (indices.n_elements() == 0)?
+                                  (indices.size() == 0)?
                                   (new_numbers[idx]) :
                                   (new_numbers[indices.index_within_set(idx)]));
                 }
@@ -575,7 +575,7 @@ namespace internal
               if (*i != DoFHandler<1>::invalid_dof_index)
                 {
                   Assert(*i<new_numbers.size(), ExcInternalError());
-                  *i = (indices.n_elements() == 0)?
+                  *i = (indices.size() == 0)?
                        (new_numbers[*i]) :
                        (new_numbers[indices.index_within_set(*i)]);
                 }
@@ -602,7 +602,7 @@ namespace internal
                i=dof_handler.vertex_dofs.begin();
                i!=dof_handler.vertex_dofs.end(); ++i)
             if (*i != DoFHandler<2,spacedim>::invalid_dof_index)
-              *i = (indices.n_elements() == 0)?
+              *i = (indices.size() == 0)?
                    (new_numbers[*i]) :
                    (new_numbers[indices.index_within_set(*i)]);
             else if (check_validity)
@@ -618,7 +618,7 @@ namespace internal
                i=dof_handler.faces->lines.dofs.begin();
                i!=dof_handler.faces->lines.dofs.end(); ++i)
             if (*i != DoFHandler<2,spacedim>::invalid_dof_index)
-              *i = ((indices.n_elements() == 0) ?
+              *i = ((indices.size() == 0) ?
                     new_numbers[*i] :
                     new_numbers[indices.index_within_set(*i)]);
 
@@ -628,7 +628,7 @@ namespace internal
                    i=dof_handler.levels[level]->dof_object.dofs.begin();
                    i!=dof_handler.levels[level]->dof_object.dofs.end(); ++i)
                 if (*i != DoFHandler<2,spacedim>::invalid_dof_index)
-                  *i = ((indices.n_elements() == 0) ?
+                  *i = ((indices.size() == 0) ?
                         new_numbers[*i] :
                         new_numbers[indices.index_within_set(*i)]);
             }
@@ -667,7 +667,7 @@ namespace internal
 
                   if (idx != DoFHandler<1>::invalid_dof_index)
                     i->set_index (level, d/*, dof_handler.get_fe().dofs_per_vertex*/,
-                                  ((indices.n_elements() == 0) ?
+                                  ((indices.size() == 0) ?
                                    new_numbers[idx] :
                                    new_numbers[indices.index_within_set(idx)]));
                 }
@@ -701,7 +701,7 @@ namespace internal
                             Assert(idx != DoFHandler<2>::invalid_dof_index, ExcInternalError ());
 
                           if (idx != DoFHandler<1>::invalid_dof_index)
-                            cell->line(l)->set_mg_dof_index (level, d, ((indices.n_elements() == 0) ?
+                            cell->line(l)->set_mg_dof_index (level, d, ((indices.size() == 0) ?
                                                                         new_numbers[idx] :
                                                                         new_numbers[indices.index_within_set(idx)]));
                         }
@@ -717,7 +717,7 @@ namespace internal
               if (*i != DoFHandler<2>::invalid_dof_index)
                 {
                   Assert(*i<new_numbers.size(), ExcInternalError());
-                  *i = ((indices.n_elements() == 0) ?
+                  *i = ((indices.size() == 0) ?
                         new_numbers[*i] :
                         new_numbers[indices.index_within_set(*i)]);
                 }
@@ -744,7 +744,7 @@ namespace internal
                i=dof_handler.vertex_dofs.begin();
                i!=dof_handler.vertex_dofs.end(); ++i)
             if (*i != DoFHandler<3,spacedim>::invalid_dof_index)
-              *i = ((indices.n_elements() == 0) ?
+              *i = ((indices.size() == 0) ?
                     new_numbers[*i] :
                     new_numbers[indices.index_within_set(*i)]);
             else if (check_validity)
@@ -760,14 +760,14 @@ namespace internal
                i=dof_handler.faces->lines.dofs.begin();
                i!=dof_handler.faces->lines.dofs.end(); ++i)
             if (*i != DoFHandler<3,spacedim>::invalid_dof_index)
-              *i = ((indices.n_elements() == 0) ?
+              *i = ((indices.size() == 0) ?
                     new_numbers[*i] :
                     new_numbers[indices.index_within_set(*i)]);
           for (std::vector<types::global_dof_index>::iterator
                i=dof_handler.faces->quads.dofs.begin();
                i!=dof_handler.faces->quads.dofs.end(); ++i)
             if (*i != DoFHandler<3,spacedim>::invalid_dof_index)
-              *i = ((indices.n_elements() == 0) ?
+              *i = ((indices.size() == 0) ?
                     new_numbers[*i] :
                     new_numbers[indices.index_within_set(*i)]);
 
@@ -777,7 +777,7 @@ namespace internal
                    i=dof_handler.levels[level]->dof_object.dofs.begin();
                    i!=dof_handler.levels[level]->dof_object.dofs.end(); ++i)
                 if (*i != DoFHandler<3,spacedim>::invalid_dof_index)
-                  *i = ((indices.n_elements() == 0) ?
+                  *i = ((indices.size() == 0) ?
                         new_numbers[*i] :
                         new_numbers[indices.index_within_set(*i)]);
             }
@@ -815,7 +815,7 @@ namespace internal
 
                   if (idx != DoFHandler<3>::invalid_dof_index)
                     i->set_index (level, d,
-                                  ((indices.n_elements() == 0) ?
+                                  ((indices.size() == 0) ?
                                    new_numbers[idx] :
                                    new_numbers[indices.index_within_set(idx)]));
                 }
@@ -849,7 +849,7 @@ namespace internal
                             Assert(idx != DoFHandler<3>::invalid_dof_index, ExcInternalError ());
 
                           if (idx != DoFHandler<3>::invalid_dof_index)
-                            cell->line(l)->set_mg_dof_index (level, d, ((indices.n_elements() == 0) ?
+                            cell->line(l)->set_mg_dof_index (level, d, ((indices.size() == 0) ?
                                                                         new_numbers[idx] :
                                                                         new_numbers[indices.index_within_set(idx)]));
                         }
@@ -875,7 +875,7 @@ namespace internal
                             Assert(idx != DoFHandler<3>::invalid_dof_index, ExcInternalError ());
 
                           if (idx != DoFHandler<1>::invalid_dof_index)
-                            cell->quad(l)->set_mg_dof_index (level, d, ((indices.n_elements() == 0) ?
+                            cell->quad(l)->set_mg_dof_index (level, d, ((indices.size() == 0) ?
                                                                         new_numbers[idx] :
                                                                         new_numbers[indices.index_within_set(idx)]));
                         }
@@ -892,7 +892,7 @@ namespace internal
               if (*i != DoFHandler<3>::invalid_dof_index)
                 {
                   Assert(*i<new_numbers.size(), ExcInternalError());
-                  *i = ((indices.n_elements() == 0) ?
+                  *i = ((indices.size() == 0) ?
                         new_numbers[*i] :
                         new_numbers[indices.index_within_set(*i)]);
                 }