Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / communications-1.1.1 / bsc.m

diff --git a/octave_packages/communications-1.1.1/bsc.m b/octave_packages/communications-1.1.1/bsc.m
new file mode 100644 (file)
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+++ b/octave_packages/communications-1.1.1/bsc.m
@@ -0,0 +1,39 @@
+## Copyright (C) 2007 Sylvain Pelissier <sylvain.pelissier@gmail.com>
+##
+## This program 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.
+##
+## This program 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
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{y} =} bsc (@var{data}, @var{p})
+## Send @var{data} into a binary symetric channel with probability
+## @var{p} of error one each symbol.
+## @end deftypefn
+
+function [ndata] = bsc(data,p)
+       if (nargin < 1); usage('ndata = bsc(data,p)'); end
+       
+       if(isscalar(p) ~= 1 || p > 1 || p < 0)
+               error('p muste be a positive scalar less than one');
+               exit;
+       end
+       if(any(data(:) ~= floor(data(:))) || any(data(:) > 1) || any(data(:) < 0))
+               error('data must be a binary sequence');
+               exit;
+       end
+       
+       ndata = data;
+       ndata(find(data == 0)) = randsrc(size(ndata(find(data == 0)),1),size(ndata(find(data == 0)),2),[-1 -2;1-p p]);
+       ndata(find(data == 1)) = randsrc(size(ndata(find(data == 1)),1),size(ndata(find(data == 1)),2),[1 0;1-p p]);
+       ndata(find(ndata == -1)) = 0;
+       ndata(find(ndata == -2)) = 1;
+