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/*!
* \file
* \brief BCH encoder/decoder class test program
* \author Pal Frenger, Steve Peters and Adam Piatyszek
*
* -------------------------------------------------------------------------
*
* IT++ - C++ library of mathematical, signal processing, speech processing,
* and communications classes and functions
*
* Copyright (C) 1995-2008 (see AUTHORS file for a list of contributors)
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* -------------------------------------------------------------------------
*/
#include <itpp/itcomm.h>
using namespace itpp;
using namespace std;
bvec set_errors(const bvec &input, const ivec errpos)
{
bvec output = input;
for (int i = 0; i < errpos.length(); i++)
output(errpos(i)) ^= 1;
return output ;
}
int main()
{
cout << "===================================" << endl;
cout << " Test of BCH encoder/decoder " << endl;
cout << "===================================" << endl;
{
BCH bch(31, 21, 2, "3 5 5 1");
bvec input = randb(21);
bvec encoded = bch.encode(input);
bvec err = set_errors(encoded, (ivec) "1 2"); // error positions
bvec decoded = bch.decode(err);
cout << "A two error case (should be corrected)" << endl;
cout << "input = " << input << endl ;
cout << "encoded = " << encoded << endl ;
cout << "err = " << err << endl ;
cout << "decoded = " << decoded << endl ;
input = randb(21);
encoded = bch.encode(input);
err = set_errors(encoded, (ivec) "1 2 27"); // error positions
decoded = bch.decode(err);
cout << "A three error case (will cause decoding errors)" << endl;
cout << "input = " << input << endl;
cout << "encoded = " << encoded << endl;
cout << "err = " << err << endl;
cout << "decoded = " << decoded << endl << endl;
}
cout << "========================================" << endl;
cout << " Systematic vs. non-systematic test " << endl;
cout << "========================================" << endl;
{
bmat u = "0 0 0 0; 0 0 0 1; 0 0 1 0; 0 0 1 1; 0 1 0 0; 0 1 0 1; 0 1 1 0";
bmat c(u.rows(), 7);
bmat y(u.rows(), 7);
bmat decoded(u.rows(), u.cols());
BCH bch_nsys(7, 4, 1, "1 3");
BCH bch_sys(7, 4, 1, "1 3", true);
bmat f = "1 0 0 0 0 0 0; 0 1 0 0 0 0 0; 0 0 1 0 0 0 0; 0 0 0 1 0 0 0; 0 0 0 0 1 0 0; 0 0 0 0 0 1 0; 0 0 0 0 0 0 1";
cout << "Non-systematic case" << endl;
cout << "-------------------" << endl;
for (int i = 0; i < u.rows(); i++) {
c.set_row(i, bch_nsys.encode(u.get_row(i)));
cout << "Encoded " << u.get_row(i) << " to " << c.get_row(i) << endl;
y.set_row(i, f.get_row(i) + c.get_row(i));
cout << "One error added: " << y.get_row(i) << endl;
decoded.set_row(i, bch_nsys.decode(y.get_row(i)));
cout << "Decoded to:" << decoded.get_row(i) << endl << endl;
}
cout << "Systematic case" << endl;
cout << "---------------" << endl;
for (int i = 0; i < u.rows(); i++) {
c.set_row(i, bch_sys.encode(u.get_row(i)));
cout << "Encoded " << u.get_row(i) << " to " << c.get_row(i) << endl;
y.set_row(i, f.get_row(i) + c.get_row(i));
cout << "One error added: " << y.get_row(i) << endl;
decoded.set_row(i, bch_sys.decode(y.get_row(i)));
cout << "Decoded to:" << decoded.get_row(i) << endl << endl;
}
}
return 0;
}
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