X-Git-Url: https://git.creatis.insa-lyon.fr/pubgit/?p=CreaPhase.git;a=blobdiff_plain;f=octave_packages%2Fcontrol-2.3.52%2F%40tf%2F__sys_inverse__.m;fp=octave_packages%2Fcontrol-2.3.52%2F%40tf%2F__sys_inverse__.m;h=8268c7c343784d94bd2807c7ceb1b271ca8c5bfc;hp=0000000000000000000000000000000000000000;hb=f5f7a74bd8a4900f0b797da6783be80e11a68d86;hpb=1705066eceaaea976f010f669ce8e972f3734b05

diff --git a/octave_packages/control-2.3.52/@tf/__sys_inverse__.m b/octave_packages/control-2.3.52/@tf/__sys_inverse__.m
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+++ b/octave_packages/control-2.3.52/@tf/__sys_inverse__.m
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+## Copyright (C) 2009, 2011   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 -*-
+## Inversion of TF models.
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: October 2009
+## Version: 0.2
+
+function sys = __sys_inverse__ (sys)
+
+  nvec = size (sys);
+  num = sys.num;
+  den = sys.den;
+
+  if (all (nvec == 1))      # SISO
+    if (num{1,1} == 0)      # catch case num = 0
+      sys.num(1,1) = tfpoly (0);
+      sys.den(1,1) = tfpoly (1);
+    else
+      sys.num = den;
+      sys.den = num;
+    endif
+  elseif (all (nvec == 2))  # 2x2 MIMO
+    sys.num(1,1) = -den{1,1}*den{1,2}*den{2,1}*num{2,2};
+    sys.num(1,2) = den{1,1}*den{2,1}*den{2,2}*num{1,2};
+    sys.num(2,1) = den{1,1}*den{1,2}*den{2,2}*num{2,1};
+    sys.num(2,2) = -den{1,2}*den{2,1}*den{2,2}*num{1,1};  
+    sys.den(:) = den{1,1}*den{2,2}*num{1,2}*num{2,1} - den{1,2}*den{2,1}*num{1,1}*num{2,2};
+  else
+    ## I've calculated 3x3 systems with sage but the formula is quite long
+    [num, den] = tfdata (inv (ss (sys)), "tfpoly");
+    sys.num = num;
+    sys.den = den;
+  endif
+
+endfunction