qgsstatisticalsummary.h

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/***************************************************************************
  qgsstatisticalsummary.h
  --------------------------------------
  Date                 : May 2015
  Copyright            : (C) 2015 by Nyall Dawson
  Email                : nyall dot dawson at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   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 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#ifndef QGSSTATISTICALSUMMARY_H
#define QGSSTATISTICALSUMMARY_H

#include <QMap>
#include <QVariant>
#include <cmath>
#include "qgis_core.h"

/***************************************************************************
 * This class is considered CRITICAL and any change MUST be accompanied with
 * full unit tests in testqgsstatisticalsummary.cpp.
 * See details in QEP #17
 ****************************************************************************/

class CORE_EXPORT QgsStatisticalSummary
{
  public:

    enum Statistic
    {
      Count = 1,  
      CountMissing = 32770, 
      Sum = 2,  
      Mean = 4,  
      Median = 8, 
      StDev = 16, 
      StDevSample = 32, 
      Min = 64,  
      Max = 128,  
      Range = 256, 
      Minority = 512, 
      Majority = 1024, 
      Variety = 2048, 
      FirstQuartile = 4096, 
      ThirdQuartile = 8192, 
      InterQuartileRange = 16384, 
      All = Count | CountMissing | Sum | Mean | Median | StDev | Max | Min | Range | Minority | Majority | Variety | FirstQuartile | ThirdQuartile | InterQuartileRange
    };
    Q_DECLARE_FLAGS( Statistics, Statistic )

    
    QgsStatisticalSummary( QgsStatisticalSummary::Statistics stats = QgsStatisticalSummary::All );

    virtual ~QgsStatisticalSummary() = default;

    Statistics statistics() const { return mStatistics; }

    void setStatistics( QgsStatisticalSummary::Statistics stats );

    void reset();

    void calculate( const QList<double> &values );

    void addValue( double value );

    void addVariant( const QVariant &value );

    void finalize();

    double statistic( QgsStatisticalSummary::Statistic stat ) const;

    int count() const { return mCount; }

    int countMissing() const { return mMissing; }

    double sum() const { return mSum; }

    double mean() const { return mMean; }

    double median() const { return mMedian; }

    double min() const { return mMin; }

    double max() const { return mMax; }

    double range() const { return std::isnan( mMax ) || std::isnan( mMin ) ? std::numeric_limits<double>::quiet_NaN() : mMax - mMin; }

    double stDev() const { return mStdev; }

    double sampleStDev() const { return mSampleStdev; }

    int variety() const { return mValueCount.count(); }

    double minority() const { return mMinority; }

    double majority() const { return mMajority; }

    double firstQuartile() const { return mFirstQuartile; }

    double thirdQuartile() const { return mThirdQuartile; }

    double interQuartileRange() const { return std::isnan( mThirdQuartile ) || std::isnan( mFirstQuartile ) ? std::numeric_limits<double>::quiet_NaN() : mThirdQuartile - mFirstQuartile; }

    static QString displayName( QgsStatisticalSummary::Statistic statistic );

  private:

    Statistics mStatistics;

    int mCount;
    int mMissing;
    double mSum;
    double mMean;
    double mMedian;
    double mMin;
    double mMax;
    double mStdev;
    double mSampleStdev;
    double mMinority;
    double mMajority;
    double mFirstQuartile;
    double mThirdQuartile;
    QMap< double, int > mValueCount;
    QList< double > mValues;
    bool mRequiresAllValueStorage = false;
    bool mRequiresHisto = false;
};

Q_DECLARE_OPERATORS_FOR_FLAGS( QgsStatisticalSummary::Statistics )

#endif // QGSSTATISTICALSUMMARY_H