1 ## Copyright (C) 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 ## @deftypefn {Function File} {@var{str} =} tfpoly2str (@var{p})
20 ## @deftypefnx {Function File} {@var{str} =} tfpoly2str (@var{p}, @var{tfvar})
21 ## Return the string of a polynomial with string @var{tfvar} as variable.
24 ## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
28 function str = tfpoly2str (p, tfvar = "x")
30 ## TODO: simplify this ugly code
36 if (lp > 0) # first element (lowest order)
37 idx = find (p); # first non-zero element
53 str = [cs, num2str(abs (a), 4)];
56 str = [cs, __variable__(tfvar, idx-1)];
58 str = [cs, __coefficient__(a), " ", __variable__(tfvar, idx-1)];
62 if (lp > idx) # remaining elements of higher order
74 str = [str, cs, __variable__(tfvar, k-1)];
76 str = [str, cs, __coefficient__(a), " ", __variable__(tfvar, k-1)];
87 function str = __coefficient__ (a)
100 function str = __variable__ (tfvar, n)
102 str = [tfvar, "^-", num2str(n)];