Use dynamic category

dune/perftool/matrixfreeistlbackends.hh

@@ -18,8 +18,6 @@ namespace Dune {
       typedef Y range_type;
       typedef typename X::field_type field_type;
 
-      enum { category = Dune::SolverCategory::sequential };
-
       NonlinearOnTheFlyOperator(const GO& go)
         : go_(go)
         , u_(static_cast<X*>(0))
@@ -46,6 +44,11 @@ namespace Dune {
         y.axpy(alpha,temp);
       }
 
+      virtual Dune::SolverCategory::Category category() const
+      {
+        return Dune::SolverCategory::sequential;
+      }
+
     private :
       const GO& go_;
       const X* u_;