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/* -*- c++ -*- */
/*
* Copyright 2015 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio 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, or (at your option)
* any later version.
*
* GNU Radio 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 GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include <scl_list.h>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <volk/volk.h>
namespace gr {
namespace fec {
namespace code {
namespace polar {
scl_list::scl_list(const unsigned int size,
const unsigned int block_size,
const unsigned int block_power):
d_list_size(size),
d_num_buff_elements(block_size * (block_power + 1))
{
for(unsigned int i = 0; i < 2 * size; i++){
d_path_list.push_back(new path());
}
for(unsigned int i = 0; i < size; i++){
d_path_list[i]->llr_vec = (float*) volk_malloc(sizeof(float) * d_num_buff_elements, volk_get_alignment());
memset(d_path_list[i]->llr_vec, 0, sizeof(float) * d_num_buff_elements);
d_path_list[i]->u_vec = (unsigned char*) volk_malloc(sizeof(unsigned char) * d_num_buff_elements, volk_get_alignment());
memset(d_path_list[i]->u_vec, 0, sizeof(unsigned char) * d_num_buff_elements);
d_path_list[i]->owns_vectors = true;
}
d_path_list[0]->is_active = true;
d_active_path_counter = 1;
d_active_pos = 0;
}
scl_list::~scl_list()
{
for(unsigned int i = 0; i < d_path_list.size(); i++){
delete d_path_list[i];
}
}
const path*
scl_list::optimal_path()
{
const path* temp = *std::min_element(d_path_list.begin(), d_path_list.begin() + d_active_path_counter, path_compare);
reset();
return temp;
}
void
scl_list::reset()
{
// leave 0th element active for next iteration
d_path_list[0]->path_metric = 0.0f;
for(unsigned int i = 1; i < d_path_list.size(); i++){
d_path_list[i]->is_active = false;
d_path_list[i]->path_metric = 0.0f;
}
d_active_path_counter = 1;
d_active_pos = 0;
}
void
scl_list::set_info_bit(const int bit_pos)
{
if(d_active_path_counter < d_list_size) {
const int offset = d_active_path_counter;
for(int i = 0; i < offset; i++) {
duplicate_path(d_path_list[i + offset], d_path_list[i]);
d_path_list[i]->path_metric = update_path_metric(d_path_list[i]->path_metric,
d_path_list[i]->llr_vec[bit_pos], 0);
d_path_list[i + offset]->path_metric = update_path_metric
(d_path_list[i + offset]->path_metric, d_path_list[i + offset]->llr_vec[bit_pos], 1);
d_path_list[i]->u_vec[bit_pos] = 0;
d_path_list[i + offset]->u_vec[bit_pos] = 1;
}
}
else {
for(unsigned int i = 0; i < d_list_size; i++) {
branch_paths(d_path_list[i + d_list_size], d_path_list[i], d_path_list[i]->llr_vec[bit_pos]);
}
std::sort(d_path_list.begin(), d_path_list.end(), path_compare);
for(unsigned int i = 0; i < d_list_size; i++) {
if(!d_path_list[i]->owns_vectors) {
int t_pos = d_list_size;
while(!d_path_list[t_pos]->owns_vectors) {
t_pos++;
}
steal_vector_ownership(d_path_list[i], d_path_list[t_pos]);
d_path_list[i]->u_vec[bit_pos] = 1;
}
else{
d_path_list[i]->u_vec[bit_pos] = 0;
}
}
}
d_active_pos = 0;
}
void
scl_list::branch_paths(path* target, path* original, const float llr)
{
target->path_metric = update_path_metric(original->path_metric, llr, 1);
original->path_metric = update_path_metric(original->path_metric, llr, 0);
target->llr_vec = original->llr_vec;
target->u_vec = original->u_vec;
}
void
scl_list::steal_vector_ownership(path* target, path* original)
{
memcpy(original->llr_vec, target->llr_vec, sizeof(float) * d_num_buff_elements);
memcpy(original->u_vec, target->u_vec, sizeof(unsigned char) * d_num_buff_elements);
target->llr_vec = original->llr_vec;
target->u_vec = original->u_vec;
target->owns_vectors = true;
original->owns_vectors = false;
}
void
scl_list::duplicate_path(path* target, const path* original)
{
memcpy(target->llr_vec, original->llr_vec, sizeof(float) * d_num_buff_elements);
memcpy(target->u_vec, original->u_vec, sizeof(unsigned char) * d_num_buff_elements);
target->path_metric = original->path_metric;
d_active_path_counter++;
target->is_active = true;
}
float
scl_list::update_path_metric(const float last_pm, const float llr,
const float ui) const
{
if((ui == 0 && llr > 0.0f) || (ui == 1 && llr < 0.0f)){
// if(ui == (unsigned char) (0.5 * 1 - copysignf(1.0f, llr))){
return last_pm;
}
return last_pm + fabs(llr);
}
void
scl_list::set_frozen_bit(const unsigned char frozen_bit, const int bit_pos)
{
for(unsigned int i = 0; i < d_active_path_counter; i++){
d_path_list[i]->u_vec[bit_pos] = frozen_bit;
d_path_list[i]->path_metric = update_path_metric(d_path_list[i]->path_metric,
d_path_list[i]->llr_vec[bit_pos],
frozen_bit);
}
d_active_pos = 0;
}
path::path():
path_metric(0.0f), owns_vectors(false), is_active(false), llr_vec(NULL), u_vec(NULL)
{
}
path::~path(){
if(owns_vectors){
volk_free(llr_vec);
volk_free(u_vec);
}
}
} /* namespace polar */
} /* namespace code */
} /* namespace fec */
} /* namespace gr */
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