//# Copyright (C) 2000,2001
//# Associated Universities, Inc. Washington DC, USA.
//#
//# This library is free software; you can redistribute it and/or modify it
//# under the terms of the GNU Library General Public License as published by
//# the Free Software Foundation; either version 2 of the License, or (at your
//# option) any later version.
//#
//# This library 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 Library General Public
//# License for more details.
//#
//# You should have received a copy of the GNU Library General Public License
//# along with this library; if not, write to the Free Software Foundation,
//# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
//#
//# Correspondence concerning AIPS++ should be addressed as follows:
//#        Internet email: casa-feedback@nrao.edu.
//#        Postal address: AIPS++ Project Office
//#                        National Radio Astronomy Observatory
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//#

#ifndef SCIMATH_CHAUVENETCRITERIONSTATISTICS_H
#define SCIMATH_CHAUVENETCRITERIONSTATISTICS_H

#include <casacore/casa/aips.h>

#include <casacore/scimath/StatsFramework/ConstrainedRangeStatistics.h>

#include <set>
#include <utility>

namespace casacore {

// Class to calculate statistics using the so-called Chauvenet criterion. This
// method iteratively calculates statistics by discarding outliers on the basis
// of Chauvenet's criterion, until the specified maximum number of iterations is
// reached, or the final iteration results in no additional points being
// discarded. Alternatively, one can specify a z-score which indicates the
// number of standard deviations beyond which to discard points, which is held
// fixed while iterating.
//
// When instantiated, objects of this class use a
// ConstrainedRangeQuantileComputer object for computing quantile-like
// statistics. See class documentation for StatisticsAlgorithm for details of
// QuantileComputer classes.

template <
    class AccumType, class DataIterator, class MaskIterator=const Bool*,
    class WeightsIterator=DataIterator
>
class ChauvenetCriterionStatistics
    : public ConstrainedRangeStatistics<CASA_STATP> {
public:

    ChauvenetCriterionStatistics() = delete;

    // If <src>zscore</src> is not negative, use that value to discard outliers
    // beyond zscore standard deviations from the mean, and compute statistics
    // based on the remaining data. If <src>zscore</src> is negative, use
    // Chauvenet's Criterion to determine which outliers to discard.
    // <src>maxIterations</src> is the maximum number of iterations to use
    // before stopping. If negative, continue iterating until the set zscore or
    // Chauvenet's criterion is met (ie that there are no remaining outliers).
    ChauvenetCriterionStatistics(Double zscore=-1, Int maxIterations=0);

    ChauvenetCriterionStatistics(
        const ChauvenetCriterionStatistics<CASA_STATP>& other
    );

    virtual ~ChauvenetCriterionStatistics();

    // copy semantics
    ChauvenetCriterionStatistics<CASA_STATP>& operator=(
        const ChauvenetCriterionStatistics<CASA_STATP>& other
    );

    // Clone this instance
    virtual StatisticsAlgorithm<CASA_STATP>* clone() const;
 
    // get the algorithm that this object uses for computing stats
    virtual StatisticsData::ALGORITHM algorithm() const {
        return StatisticsData::CHAUVENETCRITERION;
    };

    // reset object to initial state. Clears all private fields including data,
    // accumulators, global range. It does not affect the fence factor (_f),
    // which was set at object construction.
    virtual void reset();

    // This class does not allow statistics to be calculated as datasets are
    // added, so an exception will be thrown if <src>c</src> is True.
    void setCalculateAsAdded(Bool c);

    // get the number of iterations
    uInt getNiter() const { return _niter; }

private:

    Double _zscore{-1};
    Int _maxIterations{0};
    Bool _rangeIsSet{False};
    uInt _niter{0};

    void _setRange();
};

}

#ifndef CASACORE_NO_AUTO_TEMPLATES
#include <casacore/scimath/StatsFramework/ChauvenetCriterionStatistics.tcc>
#endif

#endif
