[assembler.local.codim0] add LocalOperatorApplicator

dune/gdt/assembler/local/codim0.hh

@@ -20,6 +20,7 @@
 #include <dune/stuff/grid/walker/wrapper.hh>
 #include <dune/stuff/la/container/interfaces.hh>
 
+#include <dune/gdt/discretefunction/default.hh>
 #include <dune/gdt/localoperator/interface.hh>
 #include <dune/gdt/localoperator/interfaces.hh>
 #include <dune/gdt/localfunctional/interface.hh>
@@ -169,6 +170,49 @@ private:
 }; // class LocalVolumeTwoFormAccumulator
 
 
+template <class GridViewType, class LocalOperatorType, class SourceType, class RangeType>
+class LocalOperatorApplicator : public Stuff::Grid::internal::Codim0Object<GridViewType>
+{
+  static_assert(is_local_operator<LocalOperatorType>::value,
+                "LocalOperatorType has to be derived from LocalOperatorInterface!");
+  static_assert(Stuff::is_localizable_function<SourceType>::value,
+                "SourceType has to be derived from Stuff::LocalizableFunctionInterface!");
+  static_assert(is_discrete_function<RangeType>::value, "RangeType has to be a DiscreteFunctionDefault!");
+  typedef Stuff::Grid::internal::Codim0Object<GridViewType> BaseType;
+
+public:
+  using typename BaseType::EntityType;
+
+  LocalOperatorApplicator(const GridViewType& grid_view, const LocalOperatorType& local_operator,
+                          const SourceType& source, RangeType& range,
+                          const Stuff::Grid::ApplyOn::WhichEntity<GridViewType>& where)
+    : grid_view_(grid_view)
+    , local_operator_(local_operator)
+    , source_(source)
+    , range_(range)
+    , where_(where)
+  {
+  }
+
+  virtual bool apply_on(const GridViewType& grid_view, const EntityType& entity) const
+  {
+    return where_.apply_on(grid_view, entity);
+  }
+
+  virtual void apply_local(const EntityType& entity)
+  {
+    local_operator_.apply(source_, *range_.local_discrete_function(entity));
+  }
+
+private:
+  const GridViewType& grid_view_;
+  const LocalOperatorType& local_operator_;
+  const SourceType& source_;
+  RangeType& range_;
+  const Stuff::Grid::ApplyOn::WhichEntity<GridViewType>& where_;
+}; // class LocalOperatorApplicator
+
+
 namespace LocalAssembler {