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diff --git a/source/dofs/dof_renumbering.cc b/source/dofs/dof_renumbering.cc
index cf5649bdc672b41af0352f89d98d4785ec5471cc..2d320265e3fa7a37c50c159b313f8db0ca548ebf 100644 (file)
--- a/source/dofs/dof_renumbering.cc
+++ b/source/dofs/dof_renumbering.cc
@@ -1215,6 +1215,14 @@ namespace DoFRenumbering
         }
       else
         {
+          // this is a terminal cell. we need to renumber its DoF indices. there
+          // are now three cases to decide:
+          // - this is a sequential triangulation: we can just go ahead and number
+          //   the DoFs in the order in which we encounter cells. in this case,
+          //   all cells are actually locally owned
+          // - if this is a parallel::distributed::Triangulation, then we only
+          //   need to work on the locally owned cells since they contain
+          //   all locally owned DoFs.
           if (cell->is_locally_owned())
             {
               // first get the existing DoF indices