Fix test

dune/solvers/test/multigridtest.cc

@@ -44,7 +44,7 @@ struct MultigridTestSuite
         bool passed = true;
 
         using Problem =
-            SymmetricSampleProblem<1, typename GridType::LevelGridView>;
+            SymmetricSampleProblem<blocksize, typename GridType::LevelGridView>;
         Problem p(grid.levelGridView(grid.maxLevel()));
 
         typedef typename Problem::Vector Vector;