interface changed in gridfactory

dune/multimesh/mmgridfactory.hh

@@ -8,6 +8,8 @@
 #include <vector>
 
 #include <dune/common/hybridutilities.hh>
+#include <dune/common/to_unique_ptr.hh>
+#include <dune/common/version.hh>
 #include <dune/common/std/type_traits.hh>
 #include <dune/grid/common/gridfactory.hh>
 
@@ -147,6 +149,7 @@ namespace Dune
      * Create n copies of the grid and store it in unique_pointers
      * inside the multimesh grid.
      **/
+#if DUNE_VERSION_LTE(DUNE_GRID,2,7)
     virtual Grid* createGrid () override
     {
       Grid* multimesh = new Grid{};
@@ -154,6 +157,15 @@ namespace Dune
         multimesh->grids_.emplace_back(gridFactory->createGrid());
       return multimesh;
     }
+#else
+    virtual ToUniquePtr<Grid> createGrid () override
+    {
+      std::unique_ptr<Grid> multimesh{std::make_unique<Grid>()};
+      for (auto& gridFactory : gridFactories_)
+        multimesh->grids_.emplace_back(gridFactory->createGrid());
+      return std::move(multimesh);
+    }
+#endif
 
   private:
     std::vector<std::unique_ptr<GridFactory<HostGrid>>> gridFactories_;