Index: mttroot/mtt/lib/control/PPP/ppp_indices.m
==================================================================
--- mttroot/mtt/lib/control/PPP/ppp_indices.m
+++ mttroot/mtt/lib/control/PPP/ppp_indices.m
@@ -1,31 +1,48 @@
-function indices = ppp_indices (names,sympar)
+function indices = ppp_indices (names,sympar,sympars)
 
   ## usage:  indices = ppp_indices (names,sympar)
   ##
   ## names: column vector of component names
-  ## sympar: mtt-generated data structure od symbolic parameters
+  ## sympar symbolic parameter structure for system
+  ## sympars symbolic parameter structure for sensitivity system
+ 
+
+  ## Returns a matrix indices with 3 columns, one row per name
+  ## First  col: index of ith parameter of sensitivity system
+  ## Second col: index of ith sensitivity parameter of sensitivity system
+  ## Third col : index of ith parameter of system
+  ## Copyright (C) 2002 by Peter J. Gawthrop
 
-
+  ## Sanity check
+  if nargin<3
+    printf("Usage: ppp_indices (names,sympar,sympars)\n");
+    return
+  endif
+  
   ## Set up the
   indices = [];
   [n,m] = size(names);
   for i = 1:n
     p_name = deblank(names(i,:));
     s_name = sprintf("%ss", p_name);
-    if struct_contains(sympar, p_name)
-      i_p = eval(sprintf("sympar.%s;", p_name));
-      if struct_contains(sympar, s_name)
-	i_s = eval(sprintf("sympar.%s;", s_name));
-	indices_i = eval(sprintf("[%i,%i];", i_p, i_s));
-	indices = [indices; indices_i];
+    if struct_contains(sympars, p_name)
+      i_ps = eval(sprintf("sympars.%s;", p_name));
+      if struct_contains(sympars, s_name)
+	i_s = eval(sprintf("sympars.%s;", s_name));
+	if struct_contains(sympar, p_name)
+	  i_p = eval(sprintf("sympar.%s;", p_name));
+	  indices_i = eval(sprintf("[%i,%i,%i];", i_ps, i_s, i_p));
+	  indices = [indices; indices_i];
+	else
+	  printf("Parameter %s does not exist in sympar: ignoring\n", p_name)
+	endif
       else
-	printf("Sensitivity parameter %s does not exist: ignoring \
+	printf("Sensitivity parameter %s does not exist in sympars: ignoring \
 	parameter %s\n", s_name, p_name);
       endif
     else
-      printf("Parameter %s does not exist: ignoring\n", p_name)
+      printf("Parameter %s does not exist in sympars: ignoring\n", p_name)
     endif
   endfor
-  
 
 endfunction

Index: mttroot/mtt/lib/control/PPP/ppp_ippp.m
==================================================================
--- mttroot/mtt/lib/control/PPP/ppp_ippp.m
+++ mttroot/mtt/lib/control/PPP/ppp_ippp.m
@@ -1,15 +1,15 @@
 function i_ppp = ppp_ippp (n_ppp,sympar,sympars)
 
   ## usage:  i_ppp = ppp_ippp (n_ppp,sympar,sympars)
   ## nppp   number of ppp parameters
-  ## sympar symbolic parameter structure for system
+  ## sympars symbolic parameter structure for system
   ## sympar symbolic parameter structure for sensitivity system
   ## Returns a matrix i_ppp with n_ppp rows and 3 columns
   ## First  col: index of ith ppp parameter of sensitivity system
   ## Second col: index of ith ppp sensitivity parameter of sensitivity system
-  ## Third col : index of ith ppp sensitivity parameter of system
+  ## Third col : index of ith ppp  parameter of system
   ## Copyright (C) 2002 by Peter J. Gawthrop
 
   i_ppp = [];
   for i=1:n_ppp
     i_ppp_i = eval(sprintf("[sympars.ppp_%i, sympars.ppp_%is \