dither.hpp

// Copyright (c) 2009, Willow Garage, Inc.
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// \author Kevin Watts
 
#ifndef CONTROL_TOOLBOX__DITHER_HPP_
#define CONTROL_TOOLBOX__DITHER_HPP_
 
#include <math.h>
#include <cstdlib>
#include <ctime>
#include <random>
 
#include "rcutils/logging_macros.h"
 
namespace control_toolbox
{
/***************************************************/
class Dither
{
public:
  Dither();
 
  double update();
 
  /*
  *\brief Dither gets an amplitude, must be >0 to initialize
  *
  *\param amplitude Amplitude of white noise output
  *\param seed Random seed for white noise
  */
  bool init(const double & amplitude, const double & seed)
  {
    if (amplitude < 0.0) {
      RCUTILS_LOG_ERROR("Dither amplitude not set properly. Amplitude must be >0.");
      return false;
    }
 
    amplitude_ = amplitude;
 
    // seed generator for reproducible sequence of random numbers
    generator_.seed(static_cast<unsigned int>(seed));
 
    return true;
  }
 
  /*
  *\brief Generate a random number with random_device for non-deterministic random numbers
  */
  static double generateRandomSeed()
  {
    std::random_device rdev{};
    return static_cast<double>(rdev());
  }
 
private:
  double amplitude_; 
  double saved_value_;
  bool has_saved_value_;
  std::mt19937 generator_; 
};
}  // namespace control_toolbox
 
#endif  // CONTROL_TOOLBOX__DITHER_HPP_