[d6dad2]: inst / bsc.m Maximize Restore History

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bsc.m    42 lines (35 with data), 1.6 kB

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## 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 symmetric channel with probability
## @var{p} of error one each symbol.
## @end deftypefn
function ndata = bsc (data, p)
if (nargin < 1)
print_usage ();
endif
if (isscalar (p) ~= 1 || p > 1 || p < 0)
error ("p must be a positive scalar less than one");
endif
if (any (data(:) ~= floor (data(:))) || any (data(:) > 1) || any (data(:) < 0))
error ("data must be a binary sequence");
endif
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;
endfunction