--- a/scripts/control/system/sysdimensions.m
+++ b/scripts/control/system/sysdimensions.m
@@ -80,13 +80,13 @@
   m = length(sysgetsignals(sys,"in"));
   p = length(sysgetsignals(sys,"out"));
   yd = sys.yd;
-  valid_options = list("all","cst","dst","st","in","out");
-  valid_values = list(n,n,nz,n+nz,m,p);
+  valid_options = {"all","cst","dst","st","in","out"};
+  valid_values = {n,n,nz,n+nz,m,p};
 
   valid_opt = 0;
   for ii=1:length(valid_options)
-    if(strcmp(nth(valid_options,ii),opt))
-      n = nth(valid_values,ii);
+    if(strcmp(valid_options{ii},opt))
+      n = valid_values{ii};
       valid_opt = 1;
       if(ii > 1 & nargout > 1)
         warning("opt=%s, %d output arguments requested",opt,nargout);