Compare by first PID and then element ID

Author: lindsayad

include/base/dof_object.h

@@ -1380,6 +1380,23 @@ struct CompareDofObjectsByID
   }
 };
 
+struct CompareDofObjectsByPIDAndThenID
+{
+  bool operator()(const DofObject * a,
+                  const DofObject * b) const
+  {
+    libmesh_assert (a);
+    libmesh_assert (b);
+
+    if (a->processor_id() < b->processor_id())
+      return true;
+    if (b->processor_id() < a->processor_id())
+      return false;
+
+    return a->id() < b->id();
+  }
+};
+
 } // namespace libMesh
 
 

include/base/ghosting_functor.h

@@ -229,7 +229,7 @@ class GhostingFunctor : public ReferenceCountedObject<GhostingFunctor>
    * What elements do we care about and what variables do we care
    * about on each element?
    */
-  typedef std::map<const Elem*, const CouplingMatrix*, CompareDofObjectsByID> map_type;
+  typedef std::map<const Elem*, const CouplingMatrix*, CompareDofObjectsByPIDAndThenID> map_type;
 
   /**
    * For the specified range of active elements, what other elements