MinMaxScaler.h

/*
 * MinMaxScaler.h
 *
 * (c) 2015 Sofian Audry        :: info(@)sofianaudry(.)com
 * (c) 2015 Thomas O Fredericks :: tof(@)t-o-f(.)info
 *
 * 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 MIN_MAX_SCALER_H_
#define MIN_MAX_SCALER_H_
 
#include "PqCore.h"
#include "MovingFilter.h"
 
namespace pq {
 
class MinMaxScaler : public MovingFilter {
public:
  MinMaxScaler(Engine& engine = Engine::primary());
 
  MinMaxScaler(float timeWindow, Engine& engine = Engine::primary());
 
  virtual ~MinMaxScaler() {}
 
  float minValue() const { return _smoothedMinValue; }
 
  float maxValue() const { return _smoothedMaxValue; }
 
  virtual void reset();
 
  virtual void reset(float estimatedMeanValue);
 
  virtual void reset(float estimatedMinValue, float estimatedMaxValue);
 
  virtual float put(float value);
 
  virtual float filter(float value);
 
public:
  virtual void step();
 
  // Minimum value ever put (decays over time if time window is finite).
  float _minValue;
 
  // Maximum value ever put (decays over time if time window is finite).
  float _maxValue;
 
  // Smoothed minimum value.
  float _smoothedMinValue;
 
  // Smoothed minimum value.
  float _smoothedMaxValue;
 
private:
  // Internal use: Helper functions used to compute alpha values.
  float _alphaMinMax() const;
  float _alphaSmoothed(bool finiteTimeWindow) const;
  float _smoothedTimeWindow(bool finiteTimeWindow) const;
};
 
}
 
#endif