added EntitySet as public type in DiscreteFunction

src/amdis/gridfunctions/DiscreteFunction.hpp

@@ -36,9 +36,11 @@ namespace AMDiS
     using NodeToRangeEntry = Dune::Functions::DefaultNodeToRangeMap<SubTree>;
 
     using GridView = typename GlobalBasis::GridView;
-    using EntitySet = Dune::Functions::GridViewEntitySet<GridView, 0>;
 
   public:
+    /// Set of entities the DiscreteFunction is defined on
+    using EntitySet = Dune::Functions::GridViewEntitySet<GridView, 0>;
+
     /// Global coordinates of the EntitySet
     using Domain = typename EntitySet::GlobalCoordinate;