--- a/+time/Cdiff.m	Wed Apr 10 22:22:46 2019 +0200
+++ b/+time/Cdiff.m	Wed Apr 10 22:40:55 2019 +0200
@@ -3,7 +3,7 @@
         A, B, C
         AA, BB, CC
         G
-        k
+        dt
         t
         v, v_prev
         n
@@ -15,10 +15,10 @@
         %   A*v_tt + B*v_t + C*v = G(t)
         %   v(t0) = v0
         %   v_t(t0) = v0t
-        % starting at time t0 with timestep k
+        % starting at time t0 with timestep dt
         % Using
         % A*Dp*Dm*v_n + B*D0*v_n + C*v_n = G(t_n)
-        function obj = Cdiff(A, B, C, G, v0, v0t, k, t0)
+        function obj = Cdiff(A, B, C, G, v0, v0t, dt, t0)
             m = length(v0);
             default_arg('A', speye(m));
             default_arg('B', sparse(m,m));
@@ -31,14 +31,14 @@
             obj.G = G;
 
             % Rewrite as AA*v_(n+1) + BB*v_n + CC*v_(n-1) = G(t_n)
-            obj.AA =    A/k^2 + B/(2*k);
-            obj.BB = -2*A/k^2 + C;
-            obj.CC =    A/k^2 - B/(2*k);
+            obj.AA =    A/dt^2 + B/(2*dt);
+            obj.BB = -2*A/dt^2 + C;
+            obj.CC =    A/dt^2 - B/(2*dt);
 
-            obj.k = k;
+            obj.dt = dt;
             obj.v_prev = v0;
-            obj.v = v0 + k*v0t;
-            obj.t = t0+k;
+            obj.v = v0 + dt*v0t;
+            obj.t = t0+dt;
             obj.n = 1;
         end
 
@@ -48,14 +48,14 @@
         end
 
         function [vt,t] = getVt(obj)
-            vt = (obj.v-obj.v_prev)/obj.k; % Could be improved using u_tt = f(u))
+            vt = (obj.v-obj.v_prev)/obj.dt; % Could be improved using u_tt = f(u))
             t = obj.t;
         end
 
         function E = getEnergy(obj)
             v  = obj.v;
             vp = obj.v_prev;
-            vt = (obj.v - obj.v_prev)/obj.k;
+            vt = (obj.v - obj.v_prev)/obj.dt;
 
             E = vt'*obj.A*vt + v'*obj.C*vp;
         end
@@ -65,7 +65,7 @@
 
             obj.v_prev = obj.v;
             obj.v      = v_next;
-            obj.t = obj.t + obj.k;
+            obj.t = obj.t + obj.dt;
             obj.n = obj.n + 1;
         end
     end