--- a/+rv/+time/RungekuttaExteriorRvBdf.m	Mon Feb 18 09:00:00 2019 +0100
+++ b/+rv/+time/RungekuttaExteriorRvBdf.m	Tue Mar 05 10:53:34 2019 +0100
@@ -15,13 +15,6 @@
                         % 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
-        viscosity % Total viscosity
-        residualViscosity % Residual viscosity
-        firstOrderViscosity % first order viscosity
-        dvdt % Evaluated time derivative in residual
-        Df % Evaluated flux in residual
     end
     methods
         function obj = RungekuttaExteriorRvBdf(F, k, t0, v0, RV, rkOrder, bdfOrders)
@@ -36,22 +29,11 @@
             obj.coeffs = struct('s',s,'a',a,'b',b,'c',c);
         
             obj.RV = RV;
-            %  TBD: Decide on if the initialization of the previous stages used by
-            %       the BDF should be done here, or if it should be checked for each
-            %       step taken.
-            %       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.viscosity = zeros(size(v0));
-            obj.firstOrderViscosity = zeros(size(v0));
-            obj.residualViscosity = zeros(size(v0));
-            obj.dvdt = zeros(size(v0));
-            obj.Df = zeros(size(v0));
         end
 
         function [v, t] = getV(obj)
@@ -60,31 +42,42 @@
         end
 
         function state = getState(obj)
-            state = struct('v', obj.v, 'dvdt', obj.dvdt, 'Df', obj.Df, 'viscosity', obj.viscosity, 'residualViscosity', obj.residualViscosity, 'firstOrderViscosity', obj.firstOrderViscosity, 't', obj.t);
+            if (size(obj.v_prev,2) >=  obj.lowerBdfOrder)
+                dvdt = obj.DvDt.evaluate(obj.v, obj.v_prev, obj.k);
+                [viscosity, Df, firstOrderViscosity, residualViscosity] = obj.RV.evaluate(obj.v, dvdt);
+            else
+                viscosity = zeros(size(obj.v));
+                dvdt = zeros(size(obj.v));
+                Df = zeros(size(obj.v));
+                firstOrderViscosity = zeros(size(obj.v));
+                residualViscosity = zeros(size(obj.v));
+            end
+            state = struct('v', obj.v, 'dvdt', dvdt, 'Df', Df, 'viscosity', viscosity, 'residualViscosity', residualViscosity, 'firstOrderViscosity', firstOrderViscosity, 't', obj.t);
         end
 
         function obj = step(obj)
-            % Store current time level and update v_prev
-            numStoredStages = size(obj.v_prev,2);
-            if (numStoredStages < obj.upperBdfOrder)
+            nStoredStages = size(obj.v_prev,2);
+
+            %Calculate viscosity for the new time level
+            if (nStoredStages >=  obj.lowerBdfOrder)
+                viscosity = obj.RV.evaluateViscosity(obj.v, obj.DvDt.evaluate(obj.v, obj.v_prev, obj.k));
+            else
+                viscosity = zeros(size(obj.v));
+            end
+
+             % Store current time level and update v_prev
+            if (nStoredStages < 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
 
             % Fix the viscosity of the RHS function F
-            F_visc = @(v,t) obj.F(v,t,obj.viscosity);
+            F_visc = @(v,t) obj.F(v, t, 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 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.firstOrderViscosity, obj.residualViscosity] = obj.RV.evaluate(obj.v,obj.dvdt);
-            end
         end
     end
 end
\ No newline at end of file