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diff --git a/modules/cacsd/macros/balreal.sci b/modules/cacsd/macros/balreal.sci
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+// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
+// Copyright (C) INRIA -
+//
+// This file must be used under the terms of the CeCILL.
+// This source file is licensed as described in the file COPYING, which
+// you should have received as part of this distribution.  The terms
+// are also available at
+// http://www.cecill.info/licences/Licence_CeCILL_V2.1-en.txt
+
+
+function [slb,u]=balreal(a)
+
+    [lhs,rhs]=argn(0)
+
+    if typeof(a)<>"state-space" then error(91,1),end
+    [a,b,c,d,x0,dom]=a(2:7);
+    if dom==[] then error(96,1),end
+    domain="c";
+    if dom<>"c" then domain="d",end
+    wc=lyap(a',-b*b',domain)
+    wo=lyap(a,-c'*c,domain)
+    r=chol(wo);x=r*wc*r';[u,s,v]=svd(x);s=diag(s);
+    ns=size(s,"*");
+    lli=sqrt(sqrt(s));ll=ones(ns,1)./lli
+    ri=inv(r)*v;r=v'*r;
+    a=r*a*ri;b=r*b;c=c*ri
+    a=diag(ll)*a*diag(lli)
+    b=diag(ll)*b
+    c=c*diag(lli)
+    slb=syslin(dom,a,b,c,d,diag(ll)*r*x0),
+    if lhs==2 then u=ri*diag(lli),end
+endfunction