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--- /dev/null
+++ b/scripts/control/parallel.m
@@ -0,0 +1,62 @@
+# Copyright (C) 1996 A. Scottedward Hodel 
+#
+# This file is part of Octave. 
+#
+# Octave is free software; you can redistribute it and/or modify it 
+# under the terms of the GNU General Public License as published by the 
+# Free Software Foundation; either version 2, or (at your option) any 
+# later version. 
+# 
+# Octave is distributed in the hope that it will be useful, but WITHOUT 
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License 
+# for more details.
+# 
+# You should have received a copy of the GNU General Public License 
+# along with Octave; see the file COPYING.  If not, write to the Free 
+# Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. 
+ 
+function sysp = parallel(Asys,Bsys)
+# function sysp = parallel(Asys,Bsys)
+# Forms the parallel connection of two systems.
+#
+#              ____________________
+#              |      ________    |
+#     u  ----->|----> | Asys |--->|----> y1
+#         |    |      --------    |
+#         |    |      ________    |
+#         |--->|----> | Bsys |--->|----> y2
+#              |      --------    |
+#              --------------------
+#                   Ksys
+
+# Written by David Clem August 15, 1994
+# completely rewritten Oct 1996 a s hodel
+# SYS_INTERNAL accesses members of system structure
+# $Revision: 1.1.1.1 $
+
+  if(nargin != 2)
+    usage("sysp = parallel(Asys,Bsys)");
+  endif
+  if(! is_struct(Asys) )
+    error("1st input argument is not a system data structure")
+  elseif (! is_struct(Bsys) )
+    error("2nd input argument is not a system data structure")
+  endif
+  mA = rows(Asys.inname);
+  mB = rows(Bsys.inname);
+  if(mA != mB)
+    error(["Asys has ",num2str(mA)," inputs, Bsys has ",num2str(mB)," inputs"]);
+  endif
+  sysp = sysgroup(Asys,Bsys);
+  sysD = ss2sys([],[],[],[eye(mA);eye(mA)]);
+  
+  #disp("sysp=")
+  #sysout(sysp)
+  #disp("sysD")
+  #sysout(sysD)
+
+  sysp = sysmult(sysp,sysD);
+  sysp = syschnames(sysp,"in",1:mA,Asys.inname);
+  
+endfunction