1 files changed, 48 insertions, 0 deletions
diff --git a/modules/cacsd/macros/dscr.sci b/modules/cacsd/macros/dscr.sci
new file mode 100755
index 000000000..ce3e4e879
--- /dev/null
+++ b/modules/cacsd/macros/dscr.sci
@@ -0,0 +1,48 @@
+// 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 [f,r]=dscr(a,dt,m)
+
+    [lhs,rhs]=argn(0);
+    if type(dt)<>1 then
+        error(msprintf(gettext("%s: Wrong type for input argument #%d: A real expected.\n"),"dscr",2))
+    end
+    if size(dt,"*")<>1 then
+        error(msprintf(gettext("%s: Wrong size for input argument #%d: A scalar expected.\n"),"dscr",2))
+    end
+    if ~isreal(dt) then
+        error(msprintf(gettext("%s: Input argument #%d must be real.\n"),"dscr",2))
+    end
+
+    if dt<=0 then
+        error(msprintf(gettext("%s: Input argument #%d must be strictly positive.\n"),"dscr",2))
+    end
+
+    select typeof(a)
+    case "rational" then
+        a=tf2ss(a);
+        [a,b,c,d,x0,dom]=a(2:7);
+    case "state-space" then
+        [a,b,c,d,x0,dom]=a(2:7)
+    else
+        error(97,1),
+    end;
+    if dom<>"c" then
+        warning(msprintf(gettext("%s: Input argument %d is assumed continuous time.\n"),"dscr",1))
+    end
+    [n1,m1]=size(b),
+    s=expm([a,b;0*ones(m1,n1+m1)]*dt),
+    f=s(1:n1,1:n1);g=s(1:n1,n1+1:n1+m1);
+    if rhs==3 then
+        s=expm([-a,m;0*a a']*dt),
+        r=f*s(1:n1,n1+1:n1+n1),
+    end;
+    f=syslin(dt,f,g,c,d,x0)
+endfunction