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/* -*- c++ -*- */
/*
* Copyright 2020 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifndef INCLUDED_DIGITAL_ADAPTIVE_ALGORITHM_H
#define INCLUDED_DIGITAL_ADAPTIVE_ALGORITHM_H
#include <gnuradio/digital/api.h>
#include <gnuradio/digital/constellation.h>
#include <gnuradio/math.h>
#include <algorithm>
#include <cmath>
#include <vector>
namespace gr {
namespace digital {
enum class adaptive_algorithm_t { LMS, NLMS, CMA };
class adaptive_algorithm;
typedef std::shared_ptr<adaptive_algorithm> adaptive_algorithm_sptr;
class DIGITAL_API adaptive_algorithm
: public std::enable_shared_from_this<adaptive_algorithm>
{
protected:
const adaptive_algorithm_t d_algorithm_type;
const constellation_sptr d_constellation;
public:
virtual ~adaptive_algorithm() {}
adaptive_algorithm(adaptive_algorithm_t alg_type, constellation_sptr cons)
: d_algorithm_type(alg_type), d_constellation(cons)
{
}
adaptive_algorithm_sptr base() { return shared_from_this(); }
virtual void initialize_taps(std::vector<gr_complex>& taps)
{
std::fill(taps.begin(), taps.end(), gr_complex(0.0, 0.0));
taps[0] = gr_complex(1.0, 0.0); // default weights, overridden by derived classes
}
virtual gr_complex error_dd(gr_complex& wu, gr_complex& decision) const
{
// The `map_to_points` function will treat `decision` as an array pointer.
// This call is "safe" because `map_to_points` is limited by the
// dimensionality of the constellation. This class calls the
// `constellation` class default constructor, which initializes the
// dimensionality value to `1`. Thus, Only the single `gr_complex` value
// will be dereferenced.
d_constellation->map_to_points(d_constellation->decision_maker(&wu), &decision);
return decision - wu;
}
virtual gr_complex error_tr(const gr_complex& wu, const gr_complex& d_n) const
{
return d_n - wu;
}
virtual gr_complex update_tap(const gr_complex tap,
const gr_complex& in,
const gr_complex error,
const gr_complex decision) = 0;
virtual void update_taps(gr_complex* taps,
const gr_complex* in,
const gr_complex error,
const gr_complex decision,
unsigned int num_taps)
{
// default tap update until update_taps is implemented for all the alg types
// Performance can be improved in the derived algorithms by having a volk-ified
// update_taps method
for (unsigned i = 0; i < num_taps; i++) {
taps[i] = update_tap(taps[i], in[i], error, decision);
}
}
};
} // namespace digital
} // namespace gr
#endif
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