--- a/+rv/+time/RungekuttaExteriorRV.m	Fri Dec 07 13:11:53 2018 +0100
+++ b/+rv/+time/RungekuttaExteriorRV.m	Tue Dec 11 16:29:21 2018 +0100
@@ -6,17 +6,26 @@
         v       % Solution vector
         n       % Time level
         coeffs  % The coefficents used for the RK time integration
-        RV      % Residual Viscosity
-        v_prev  % Solution vector at previous time levels, used for the RV update
-        DvDt    % Function for computing the time deriative used for the RV update
-        lowerBdfOrder % Orders of the approximation of the time deriative, used for the RV update.
-                      % dictates which accuracy the boot-strapping should start from.
-        upperBdfOrder % Orders of the approximation of the time deriative, used for the RV update.
-                      % Dictates the order of accuracy used once the boot-strapping is complete.
+        
+        % Properties related to the residual viscositys
+        RV              % Residual Viscosity operator
+        viscosity       % Viscosity vector
+        v_prev          % Solution vector at previous time levels, used for the RV evaluation
+        DvDt            % Function for computing the time deriative used for the RV evaluation
+        lowerBdfOrder   % Orders of the approximation of the time deriative, used for the RV evaluation.
+                        % dictates which accuracy the boot-strapping should start from.
+        upperBdfOrder   % Orders of the approximation of the time deriative, used for the RV evaluation.
+                        % Dictates the order of accuracy used once the boot-strapping is complete.
+        
+        % Convenience properties. Only for plotting
+        residual
+        dvdt
+        Df
     end
     methods
 
-        function obj = RungekuttaExteriorRV(F, k, t0, v0, RV, rkOrder, bdfOrders)
+        % TODO: Decide on how to compute dvdt.
+        function obj = RungekuttaExteriorRV(F, k, t0, v0, RV, DvDt, rkOrder, bdfOrders)
             obj.F = F;
             obj.k = k;
             obj.t = t0;
@@ -34,11 +43,21 @@
             %       If it is moved here, then multiple branching stages can be removed in step()
             %       but this will effectively result in a plotted simulation starting from n = upperBdfOrder.
             %       In addition, the properties lowerBdfOrder and upperBdfOrder can be removed.
-            obj.lowerBdfOrder = bdfOrders.lowerBdfOrder;
-            obj.upperBdfOrder = bdfOrders.upperBdfOrder;
-            assert((obj.lowerBdfOrder >= 1) && (obj.upperBdfOrder <= 6));
-            obj.v_prev = [];
-            obj.DvDt = rv.time.BdfDerivative();
+            % obj.lowerBdfOrder = bdfOrders.lowerBdfOrder;
+            % obj.upperBdfOrder = bdfOrders.upperBdfOrder;
+            % assert((obj.lowerBdfOrder >= 1) && (obj.upperBdfOrder <= 6));
+            % obj.v_prev = [];
+            % obj.DvDt = rv.time.BdfDerivative();
+            % obj.viscosity = zeros(size(v0));
+            % obj.residual = zeros(size(v0));
+            % obj.dvdt = zeros(size(v0));
+            % obj.Df = zeros(size(v0));
+
+            % Using the ODE:
+            obj.DvDt = DvDt;
+            obj.dvdt = obj.DvDt(obj.v);
+            [obj.viscosity, obj.Df] = RV.evaluate(obj.v,obj.dvdt);
+            obj.residual = obj.dvdt + obj.Df;
         end
 
         function [v, t] = getV(obj)
@@ -47,30 +66,36 @@
         end
 
         function state = getState(obj)
-            [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);
+            state = struct('v', obj.v, 'residual', obj.residual, 'dvdt', obj.dvdt, 'Df', obj.Df, 'viscosity', obj.viscosity, 't', obj.t);
         end
 
         function obj = step(obj)
-            % Store current time level
-            numStoredStages = size(obj.v_prev,2);
-            if (numStoredStages < obj.upperBdfOrder)
-                obj.v_prev = [obj.v, obj.v_prev];
-                numStoredStages = numStoredStages+1;
-            else
-                obj.v_prev(:,2:end) = obj.v_prev(:,1:end-1);
-                obj.v_prev(:,1) = obj.v;
-            end    
+            % Store current time level and update v_prev
+            % numStoredStages = size(obj.v_prev,2);
+            % if (numStoredStages < obj.upperBdfOrder)
+            %     obj.v_prev = [obj.v, obj.v_prev];
+            %     numStoredStages = numStoredStages+1;
+            % else
+            %     obj.v_prev(:,2:end) = obj.v_prev(:,1:end-1);
+            %     obj.v_prev(:,1) = obj.v;
+            % end
+            
+            obj.dvdt = obj.DvDt(obj.v);
+            [obj.viscosity, obj.Df] = obj.RV.evaluate(obj.v,obj.dvdt);
+            obj.residual = obj.dvdt + obj.Df;
+
             % Fix the viscosity of the RHS function F
-            F_visc = @(v,t) obj.F(v,t,obj.RV.getViscosity()); %TBD: Remove state in RV?
+            F_visc = @(v,t) obj.F(v,t,obj.viscosity);
             obj.v = time.rk.rungekutta(obj.v, obj.t, obj.k, F_visc, obj.coeffs);
             obj.t = obj.t + obj.k;
             obj.n = obj.n + 1;
-            % Calculate dvdt and update RV for the new time level
-            if ((numStoredStages >=  obj.lowerBdfOrder) && (numStoredStages <= obj.upperBdfOrder))
-                dvdt = obj.DvDt.evaluate(obj.v, obj.v_prev, obj.k);
-                obj.RV.update(obj.v,dvdt);
-            end
+
+            % %Calculate dvdt and evaluate RV for the new time level
+            % if ((numStoredStages >=  obj.lowerBdfOrder) && (numStoredStages <= obj.upperBdfOrder))
+            %     obj.dvdt = obj.DvDt.evaluate(obj.v, obj.v_prev, obj.k);
+            %     [obj.viscosity, obj.Df] = obj.RV.evaluate(obj.v,obj.dvdt);
+            %     obj.residual = obj.dvdt + obj.Df;
+            % end
         end
     end
 end
\ No newline at end of file