/usr/share/octave/packages/control-2.6.2/@lti/mpower.m is in octave-control 2.6.2-1build1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 | ## Copyright (C) 2009-2014 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 @acronym{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
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