1 ## Copyright (C) 2009, 2010, 2012 Lukas F. Reichlin
3 ## This file is part of LTI Syncope.
5 ## LTI Syncope is free software: you can redistribute it and/or modify
6 ## it under the terms of the GNU General Public License as published by
7 ## the Free Software Foundation, either version 3 of the License, or
8 ## (at your option) any later version.
10 ## LTI Syncope is distributed in the hope that it will be useful,
11 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 ## GNU General Public License for more details.
15 ## You should have received a copy of the GNU General Public License
16 ## along with LTI Syncope. If not, see <http://www.gnu.org/licenses/>.
19 ## Inversion of SS models.
21 ## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
22 ## Created: October 2009
25 function sys = __sys_inverse__ (sys)
33 if (! isempty (e) || rcond (d) < eps) # dss or strictly proper ss
36 m = columns (b); # p = m (square system)
38 if (isempty (e)) # avoid testing twice?
43 sys.b = [zeros(n, m); -eye(m)];
44 sys.c = [zeros(m, n), eye(m)];
46 sys.e = [e, zeros(n, m); zeros(m, n+m)];
48 sys.stname = repmat ({""}, n+m, 1);