File indexing completed on 2024-05-12 15:57:02

 /*
  *  SPDX-FileCopyrightText: 2022 Dmitry Kazakov <dimula73@gmail.com>
  *
  *  SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #ifndef KISFILTEREDROLLINGMEAN_H
 #define KISFILTEREDROLLINGMEAN_H
 
 #include "kritaglobal_export.h"
 
 #include <vector>
 #include <boost/circular_buffer.hpp>
 #include <QtGlobal>
 
 /**
  * A special class that calculates a rolling mean of the
  * values stream, but filtering out random extreme deviations.
  *
  * On each step the algorithm sorts the entire sampling window
  * and drops a small portion of the lowest and the highest
  * values. The rest of the values are used to calculate the
  * mean of the window.
  *
  * Basically, it takes the median and a few surrounding values
  * to calculate the mean.
  *
  * PS:
  * The actualy implementation does a few optimizations. For
  * example, it doesn't sort the entire range. But the idea is
  * the same.
  */
 class KRITAGLOBAL_EXPORT KisFilteredRollingMean
 {
 public:
     /**
      * Creates a mean accumulator
      *
      * \p windowSize is the size of the samples window
      * \p effectivePortion the portion of the samples window
      *    that is used for actual mean calclulation. On each
      *    side of the sorted range (0.5 * (1.0 - effectivePortion) *
      *    windowSize) values are dropped and are not counted for
      *    the mean calculation.
      */
     KisFilteredRollingMean(int windowSize, qreal effectivePortion);
 
     /**
      * Adds a value for the rolling mean calculation. The
      * complexity of the call is O(1).
      */
     void addValue(qreal value);
 
     /**
      * Calculates the filtered mean value of the current range.
      * The function is slow, its complexity is O(N) + O(N*log(M)),
      * where N is the size of the rolling window, M is the number
      * of elements dropped from the window
      * (1.0 - effectivePortion) * windowSize).
      */
     qreal filteredMean() const;
 
     /**
      * Returns true if the accumulator has at least some value
      */
     bool isEmpty() const;
 
 private:
     boost::circular_buffer<qreal> m_values;
     qreal m_rollingSum;
     qreal m_effectivePortion;
     mutable std::vector<qreal> m_cutOffBuffer;
 };
 
 #endif // KISFILTEREDROLLINGMEAN_H