dither.h

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#ifndef CONTROL_TOOLBOX__DITHER_H
#define CONTROL_TOOLBOX__DITHER_H

#include <cstdlib>
#include <ctime>
#include <math.h>
#include <random>
#include <ros/ros.h>

namespace control_toolbox {

/***************************************************/
class Dither
{
public:

  Dither();

  ~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)
    {
      ROS_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_;
  double s_;
  double x_;
  std::mt19937 generator_;   
};
}

#endif