--- a/+time/+expint/Magnus_mp.m	Mon Jun 26 19:23:19 2017 +0200
+++ b/+time/+expint/Magnus_mp.m	Mon Jun 26 20:15:54 2017 +0200
@@ -1,16 +1,21 @@
 % Takes one time step of size k using the magnus midpoinr
 % starting from v_0 and where the function F(v,t) gives the
 % time derivatives.
-function v = Magnus_mp(v,D, t , k)
+function v = Magnus_mp(v,D, t , k,matrixexp,tol)
 
 if isa(D,'function_handle')
-   % v = krylov(k*D(t +k/2*t),v);
-%   v = expm(k*D(t +k/2))*v;
-      toler = 10^(-5);
-   expm_Arnoldi(-D,v,k,toler,100)
+    Omega = D(t +k/2);
 else
-   %v = krylov(k*D,v);
-   % v = expm(k*D)*v;
+    Omega = D;
 end
 
+switch matrixexp
+    case 'expm'
+        v = expm(k*Omega)*v;
+    case 'Arnoldi'
+        v = time.expint.expm_Arnoldi(-Omega,v,k,tol,100);
+    otherwise
+        error('No such matrix exponential evaluation')
+        
+end
 end
\ No newline at end of file