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/*!
* \file
* \brief LDPC class test program
* \author Erik G. Larsson
*
* -------------------------------------------------------------------------
*
* Copyright (C) 1995-2010 (see AUTHORS file for a list of contributors)
*
* This file is part of IT++ - a C++ library of mathematical, signal
* processing, speech processing, and communications classes and functions.
*
* IT++ 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.
*
* IT++ 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 IT++. If not, see <http://www.gnu.org/licenses/>.
*
* -------------------------------------------------------------------------
*/
#include <itpp/itcomm.h>
using std::cout;
using std::endl;
using namespace itpp;
int main()
{
LDPC_Parity_Regular H;
H.generate(200, 3, 6, "rand", "100 6");
int girth = H.cycle_removal_MGW(6);
cout << "girth=" << girth << endl;
LDPC_Generator_Systematic G;
G.construct(&H);
LDPC_Code C(&H, &G);
C.save_code("ldpc_test.codec");
LDPC_Code C1("ldpc_test.codec", &G);
cout << C << endl;
bvec bitsin = randb(C.get_nvar() - C.get_ncheck());
bvec bitsout;
C.encode(bitsin, bitsout);
it_assert(C.syndrome_check(bitsout), "syndrome check failed");
double EbN0db = 1.5;
double N0 = pow(10.0, -EbN0db / 10.0) / C.get_rate();
double sigma = sqrt(N0 / 2.0);
vec x = 1.0 + sigma * randn(C.get_nvar());
QLLRvec LLRin = C.get_llrcalc().to_qllr(2.0 * x / (N0 / 2.0));
QLLRvec LLRout(C.get_nvar());
C.bp_decode(LLRin, LLRout);
cout << LLRout.left(25) << endl;
// BLDPC code
{
cout.precision(5);
imat A = "0 -1 -1 0; -1 1 4 -1; -1 2 -1 6";
imat B = "1; -1; 2";
imat T = "0 -1 -1; 0 0 -1; -1 0 0";
imat C = "3 -1 5 -1";
imat D = "3";
imat E = "-1 -1 0";
// base matrix
imat H_b = concat_vertical(concat_horizontal(concat_horizontal(A, B), T),
concat_horizontal(concat_horizontal(C, D), E));
int Z = 4; // expansion factor
cout << endl;
cout << "expansion factor Z = " << Z << endl;
cout << "base matrix H_b =\n" << H_b << endl;
BLDPC_Parity H(H_b, Z);
cout << "expanded parity check matrix H =\n" << H.get_H() << endl;
BLDPC_Generator G(&H);
bvec in_bits = randb(H.get_nvar() - H.get_ncheck());
bvec codeword;
G.encode(in_bits, codeword);
cout << in_bits << endl << codeword << endl;
}
}
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