EMA.hpp

Go to the documentation of this file.

/* ✔ */
 
#pragma once
 
#include <AH/Settings/Warnings.hpp>
AH_DIAGNOSTIC_WERROR() // Enable errors on warnings
 
#include <stdint.h>
 
template <uint8_t K, class uint_t>
class EMA {
  public:
    EMA(uint_t initial = 0)
     : filtered((initial << K) - initial) {}
 
    void reset(uint_t value = 0) {
        filtered = (value << K) - value;
    }
 
    uint_t filter(uint_t input) {
        filtered += input;
        uint_t output = (filtered + fixedPointAHalf) >> K;
        filtered -= output;
        return output;
    }
 
    uint_t operator()(uint_t value) { return filter(value); }
 
    static_assert(
        uint_t(0) < uint_t(-1), // Check that `uint_t` is an unsigned type
        "Error: the uint_t type should be an unsigned integer, otherwise, "
        "the division using bit shifts is invalid.");
 
  private:
    uint_t filtered = 0;
    constexpr static uint_t fixedPointAHalf = K > 0 ? 1 << (K - 1) : 0;
};
 
// -------------------------------------------------------------------------- //
 
class EMA_f {
  public:
    EMA_f(float pole) : alpha(1 - pole) {}
 
    float filter(float value) {
        filtered += (value - filtered) * alpha;
        return filtered;
    }
 
    float operator()(float value) { return filter(value); }
 
  private:
    float alpha;
    float filtered = 0;
};
 
AH_DIAGNOSTIC_POP()