Index: mttroot/mtt/lib/control/PPP/ppp_lin.m
==================================================================
--- mttroot/mtt/lib/control/PPP/ppp_lin.m
+++ mttroot/mtt/lib/control/PPP/ppp_lin.m
@@ -1,7 +1,10 @@
 function [k_x,k_w,K_x,K_w,Us0,J_uu,J_ux,J_uw,J_xx,J_xw,J_ww,y_u,cond_uu] = ppp_lin(A,B,C,D,A_u,A_w,tau,Q,R,P,max_cond);
-  ## usage:   [k_x,k_w,K_x,K_w,Us0,J_uu,J_ux,J_uw,J_xx,J_xw,J_ww,y_u,cond_uu] = ppp_lin(A,B,C,D,A_u,A_w,tau,Q,R,P,max_cond)
+  ## usage:
+  ## [k_x,k_w,K_x,K_w,Us0,J_uu,J_ux,J_uw,J_xx,J_xw,J_ww,y_u,cond_uu] =
+  ##  ppp_lin(A,B,C,D,A_u,A_w,tau,Q,R,P,max_cond)
+
   ##
   ## Linear PPP (Predictive pole-placement) computation 
   ## INPUTS:
   ## A,B,C,D: system matrices
   ## A_u: composite system matrix for U* generation 
@@ -11,11 +14,11 @@
   ## A_u: square system matrix for U* generation 
   ##      same square matrix for each system input.
   ## A_w: composite system matrix for W* generation 
   ##      one square matrix (A_wi) row for each system output
   ##      each A_wi generates W*' for ith system output.
-  ## t: row vector of times for optimisation (equispaced in time)
+  ## tau: row vector of times for optimisation (equispaced in time)
   ## Q column vector of output weights (defaults to unity)
   ## OR
   ## Q matrix,  each row corresponds to time-varying weight compatible with t
   ## max_cond: Maximum condition number of J_uu (def 1/eps)
   ## OUTPUTS:
@@ -32,11 +35,11 @@
   ## Check some dimensions
   [n_x,n_u,n_y] = abcddim(A,B,C,D);
   if (n_x==-1)
     return
   endif
-
+  
   ## Default Q (output weight)
   if nargin<8
     Q = ones(n_y,1);
   endif