--- a/+time/RungekuttaRV.m	Thu Sep 27 09:30:21 2018 +0200
+++ b/+time/RungekuttaRV.m	Fri Oct 12 08:41:57 2018 +0200
@@ -29,17 +29,14 @@
         end
 
         function state = getState(obj)
-            [residual, u_t, f_x] = obj.RV.getResidual();
-            state = struct('v', obj.v, 'residual', residual, 'u_t', u_t, 'f_x', f_x, 'viscosity', obj.RV.getViscosity(), 't', obj.t);
+            [residual, u_t, grad_f] = obj.RV.getResidual();
+            state = struct('v', obj.v, 'residual', residual, 'u_t', u_t, 'grad_f', grad_f, 'viscosity', obj.RV.getViscosity(), 't', obj.t);
         end
 
         function obj = step(obj)
-            F = @(v,t) obj.F(v,t,obj.RV.getViscosity());
-            v_p = obj.v;
-            obj.v = time.rk.rungekutta(obj.v, obj.t, obj.k, F, obj.coeffs);
+            obj.v = time.rk.rungekuttaRV(obj.v, obj.t, obj.k, obj.F, obj.RV, obj.coeffs);
             obj.t = obj.t + obj.k;
             obj.n = obj.n + 1;
-            obj.RV.update(obj.v,v_p,obj.k);
         end
     end