chaos.hpp

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#pragma once

 
#include <algorithm>
#include <cmath>
#include <cstdint>
 
namespace pulp::signal {

template <typename SampleType = float>
class LogisticMapT {
public:
    static constexpr double kMinR = 3.5;
    static constexpr double kMaxR = 4.0;

    static constexpr double kEpsilon = 1.0e-6;
 
    void set_r(double r) { r_ = std::clamp(r, kMinR, kMaxR); }
    double r() const { return r_; }

    void seed(double x0) {
        seed_ = std::clamp(x0, kEpsilon, 1.0 - kEpsilon);
        x_ = seed_;
    }
 
    void reset() { x_ = seed_; }

    SampleType next() {
        x_ = std::clamp(r_ * x_ * (1.0 - x_), kEpsilon, 1.0 - kEpsilon);
        return static_cast<SampleType>(x_);
    }

    SampleType next_bipolar() { return static_cast<SampleType>(2.0) * next() - static_cast<SampleType>(1); }
 
    SampleType current() const { return static_cast<SampleType>(x_); }
 
private:
    double r_ = 3.9;
    double x_ = 0.5;
    double seed_ = 0.5;
};
 
using LogisticMap = LogisticMapT<float>;
using LogisticMap64 = LogisticMapT<double>;
 
} // namespace pulp::signal