--- /dev/null
+## Copyright (C) 2009 Lukas F. Reichlin
+##
+## This file is part of LTI Syncope.
+##
+## LTI Syncope 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 3 of the License, or
+## (at your option) any later version.
+##
+## LTI Syncope 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 LTI Syncope. If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## Matrix power of LTI objects. The exponent must be an integer.
+## Used by Octave for "sys^int".
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: October 2009
+## Version: 0.1
+
+function retsys = mpower (sys, e)
+
+ if (nargin != 2) # prevent sys = mpower (a, b, c, ...)
+ error ("lti: mpower: this is a binary operator");
+ endif
+
+ if (! is_real_scalar (e) || e != round (e))
+ error ("lti: mpower: exponent must be an integer");
+ endif
+
+ [p, m] = size (sys);
+
+ if (p != m)
+ error ("lti: mpower: system must be square");
+ endif
+
+ ex = round (abs (e)); # make sure ex is a positive integer
+
+ switch (sign (e))
+ case -1 # lti^-ex
+ sys = inv (sys);
+ retsys = sys;
+ case 0 # lti^0
+ retsys = eye (p);
+ return;
+ case 1 # lti^ex
+ retsys = sys;
+ endswitch
+
+ for k = 2 : ex
+ retsys = retsys * sys;
+ endfor
+
+endfunction