Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / control-2.3.52 / @tfpoly / minus.m

diff --git a/octave_packages/control-2.3.52/@tfpoly/minus.m b/octave_packages/control-2.3.52/@tfpoly/minus.m
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+## 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 -*-
+## Subtraction of two polynomials.  For internal use only.
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: September 2009
+## Version: 0.1
+
+function a = minus (a, b)
+
+  if (! isa (a, "tfpoly"))
+    a = tfpoly (a);
+  endif
+
+  if (! isa (b, "tfpoly"))
+    b = tfpoly (b);
+  endif
+
+  [a, b] = __make_equally_long__ (a, b);
+
+  a.poly = a.poly - b.poly;
+
+  a = __remove_leading_zeros__ (a);
+
+endfunction
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