MovingAverage.h

/*
 * MovingAverage.h
 *
 * Tool for moving averages.
 *
 * This file is part of Qualia https://github.com/sofian/qualia
 *
 * (c) 2011 Sofian Audry -- info(@)sofianaudry(.)com
 * Inspired by code by Karsten Kutza
 * http://www.ip-atlas.com/pub/nap/nn-src/bpn.txt
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef MOVINGAVERAGE_H_
#define MOVINGAVERAGE_H_
 
#include <Arduino.h>
#include <limits.h>
#include <float.h>
 
namespace pq {
 
class MovingAverage {
public:
  MovingAverage();
 
  MovingAverage(float timeWindow);
 
  virtual ~MovingAverage() {}
 
  void infiniteTimeWindow();
 
  void timeWindow(float seconds);
 
  float timeWindow() const { return _smoothTime; }
 
  bool timeWindowIsInfinite() const;
 
  void cutoff(float hz);
 
  float cutoff() const;
 
  float alpha(float sampleRate) const;
 
  void reset();
 
  virtual float update(float v, float sampleRate=1, bool forceAlpha=false);
 
  float get() { return _value; }
  float constGet() const { return _value; }
 
  unsigned int nSamples() const { return _nSamples; }
 
  void amendUpdate(float previousValue, float newValue, float sampleRate=1, bool forceAlpha=false);
 
  static void applyUpdate(float& runningValue, float newValue, float alpha);
 
  static void applyAmendUpdate(float& runningValue, float previousValue, float newValue, float alpha);
 
  static float computeUpdate(float runningValue, float newValue, float alpha);
 
  static float alpha(float sampleRate, float timeWindow, unsigned int nSamples=UINT_MAX);
 
protected:
  // The smoothing window (in seconds).
  float _smoothTime;
 
  // The current value of the exponential moving average.
  float _value;
 
  // Number of samples that have been processed thus far.
  unsigned int _nSamples;
};
 
} // namespace pq
 
#endif /* MOVINGAVERAGE_H_ */