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/*
Copyright (C) 2007, 2008, 2009, 2010, 2011 Her Majesty the Queen in
Right of Canada (Communications Research Center Canada)
Copyright (C) 2017
Matthias P. Braendli, matthias.braendli@mpb.li
Andreas Steger, andreas.steger@digris.ch
http://opendigitalradio.org
This block implements a memoryless polynom for digital predistortion.
For better performance, multiplying is done in another thread, leading
to a pipeline delay of two calls to MemlessPoly::process
*/
/*
This file is part of ODR-DabMod.
ODR-DabMod 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.
ODR-DabMod 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 ODR-DabMod. If not, see <http://www.gnu.org/licenses/>.
*/
#include "MemlessPoly.h"
#include "PcDebug.h"
#include "Utils.h"
#include <stdio.h>
#include <stdexcept>
#include <array>
#include <iostream>
#include <fstream>
#include <memory>
using namespace std;
#define NUM_COEFS 5
// By default the signal is unchanged
static const std::array<complexf, 8> default_coefficients({{
1, 0.0, 0.0, 0.0,
0.0, 0.0, 0.0, 0.0
}});
MemlessPoly::MemlessPoly(const std::string& coefs_file) :
PipelinedModCodec(),
RemoteControllable("memlesspoly"),
m_coefs_file(coefs_file)
{
PDEBUG("MemlessPoly::MemlessPoly(%s) @ %p\n",
coefs_file.c_str(), this);
RC_ADD_PARAMETER(ncoefs, "(Read-only) number of coefficients.");
RC_ADD_PARAMETER(coeffile, "Filename containing coefficients. When written to, the new file gets automatically loaded.");
load_coefficients(m_coefs_file);
start_pipeline_thread();
}
void MemlessPoly::load_coefficients(const std::string &coefFile)
{
std::vector<complexf> coefs;
if (coefFile == "default") {
std::copy(default_coefficients.begin(), default_coefficients.end(),
std::back_inserter(coefs));
}
else {
std::ifstream coef_fstream(coefFile.c_str());
if (!coef_fstream) {
throw std::runtime_error("MemlessPoly: Could not open file with coefs!");
}
int n_coefs;
coef_fstream >> n_coefs;
if (n_coefs <= 0) {
throw std::runtime_error("MemlessPoly: coefs file has invalid format.");
}
else if (n_coefs != NUM_COEFS) {
throw std::runtime_error("MemlessPoly: invalid number of coefs: " +
std::to_string(coefs.size()));
}
etiLog.log(debug, "MemlessPoly: Reading %d coefs...", n_coefs);
coefs.resize(n_coefs);
for (int n = 0; n < n_coefs; n++) {
float a, b;
coef_fstream >> a;
coef_fstream >> b;
coefs[n] = complexf(a, b);
if (coef_fstream.eof()) {
etiLog.log(error, "MemlessPoly: file %s should contains %d coefs, "
"but EOF reached after %d coefs !",
coefFile.c_str(), n_coefs, n);
throw std::runtime_error("MemlessPoly: coefs file invalid !");
}
}
}
{
std::lock_guard<std::mutex> lock(m_coefs_mutex);
m_coefs = coefs;
}
}
int MemlessPoly::internal_process(Buffer* const dataIn, Buffer* dataOut)
{
dataOut->setLength(dataIn->getLength());
const complexf* in = reinterpret_cast<const complexf*>(dataIn->getData());
complexf* out = reinterpret_cast<complexf*>(dataOut->getData());
size_t sizeOut = dataOut->getLength() / sizeof(complexf);
{
std::lock_guard<std::mutex> lock(m_coefs_mutex);
for (size_t i = 0; i < sizeOut; i += 1) {
/* Implement
a0 + a1*x + a2*x^2 + a3*x^3 + a4*x^4 + a5*x^5;
with less multiplications:
a0 + x*(a1 + x*(a2 + x*(a3 + x*(a3 + x*(a4 + a5*x)))));
*/
/* Make sure to adapt NUM_COEFS when you change this */
out[i] =
m_coefs[0] + in[i] *
( m_coefs[1] + in[i] *
( m_coefs[2] + in[i] *
( m_coefs[3] + in[i] *
( m_coefs[4] + in[i] *
( m_coefs[5] + in[i] )))));
}
}
return dataOut->getLength();
}
void MemlessPoly::set_parameter(const string& parameter, const string& value)
{
stringstream ss(value);
ss.exceptions ( stringstream::failbit | stringstream::badbit );
if (parameter == "ncoefs") {
throw ParameterError("Parameter 'ncoefs' is read-only");
}
else if (parameter == "coeffile") {
try {
load_coefficients(value);
m_coefs_file = value;
}
catch (std::runtime_error &e) {
throw ParameterError(e.what());
}
}
else {
stringstream ss;
ss << "Parameter '" << parameter <<
"' is not exported by controllable " << get_rc_name();
throw ParameterError(ss.str());
}
}
const string MemlessPoly::get_parameter(const string& parameter) const
{
stringstream ss;
if (parameter == "ncoefs") {
ss << m_coefs.size();
}
else if (parameter == "coefFile") {
ss << m_coefs_file;
}
else {
ss << "Parameter '" << parameter <<
"' is not exported by controllable " << get_rc_name();
throw ParameterError(ss.str());
}
return ss.str();
}
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