Index: mttroot/mtt/lib/control/PPP/ppp_ustar.m
==================================================================
--- mttroot/mtt/lib/control/PPP/ppp_ustar.m
+++ mttroot/mtt/lib/control/PPP/ppp_ustar.m
@@ -1,15 +1,17 @@
-function Ustar = ppp_ustar (A_u,n_u,tau,order,packed)
+function Ustar = ppp_ustar (A_u,n_u,tau,order,packed,n_zero)
 
   ## usage:  Us = ppp_ustar(A_u,n_u,tau,order,packed)
   ##
   ## Computes the U* matrix at time tau in terms of A_u
   ## n_u : Number of system inputs
   ## If tau is a vector, computes U* at each tau and puts into a row vector:
   ## If packed==1
   ##     Ustar = [Ustar(tau_1) Ustar(tau_2) ...]
   ## else Ustar = [Ustar(tau_1); Ustar(tau_2) ...]
+  ## n_zero extra zero columns appended
+
   ## Copyright (C) 1999 by Peter J. Gawthrop
   ## 	$Id$	
 
   if nargin<2
     n_u = 1;
@@ -24,10 +26,14 @@
   endif
   
   if nargin<5
     packed=1;
   endif
+  
+  if nargin<6
+    n_zero=0;
+  endif
   
 
   [n,m] = size(A_u);		# Size of composite A_u matrix
   N = m;			# Number of U* functions per input  
   nm = n/m;
@@ -58,7 +64,11 @@
     else
       Ustar = [Ustar; ustar];
     endif
   endfor
 
-
+  if (n_zero>0)
+    [N,M] = size(Ustar);
+    Ustar = [Ustar zeros(N, n_zero)];
+  endif
+  
 endfunction