ZScoreCalculator.h

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//# Copyright (C) 2000,2001
//# Associated Universities, Inc. Washington DC, USA.
//#
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//# under the terms of the GNU Library General Public License as published by
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//# $Id: HostInfoDarwin.h 21521 2014-12-10 08:06:42Z gervandiepen $

#ifndef SCIMATH_ZSCORECALCULATOR_H
#define SCIMATH_ZSCORECALCULATOR_H

#include <casacore/casa/aips.h>

#include <map>
#include <set>
#include <math.h>

namespace casacore {

/*
 * This class contains static methods related to z-scores. A z-score is the number of
 * standard deviations from the mean in a normal distribution.
 */

class ZScoreCalculator {
public:

        // compute the maximum expected zscore given the number of points
        // in a sample.
        static Double getMaxZScore(uInt64 npts);

        // Get the minimum number of points in a Gaussian distribution, such that the
        // probability that the maximum of the distribution having the specified zscore
        // is 0.5. <src>zscore</src> should be non-negative.
        static inline uInt64 zscoreToNpts(Double zscore) {
                return (uInt64)(0.5/erfc(zscore/sqrt(2)));
        }

private:
        static std::map<uInt64, Double> _nptsToMaxZScore;

};

}

#endif