elo.h

/*
    This file is part of Cute Chess.
    Copyright (C) 2008-2018 Cute Chess authors
 
    Cute Chess 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.
 
    Cute Chess 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 Cute Chess.  If not, see <http://www.gnu.org/licenses/>.
*/
 
#ifndef ELO_H
#define ELO_H
 
#include <QtGlobal>

class LIB_EXPORT Elo
{
    public:
        Elo(int wins, int losses, int draws);

        qreal diff() const;
        qreal errorMargin() const;
        qreal pointRatio() const;
        qreal drawRatio() const;
        qreal LOS() const;
 
    private:
        int m_wins;
        int m_losses;
        int m_draws;
        qreal m_mu;
        qreal m_stdev;
 
        // Elo difference
        static qreal diff(qreal p);
        // Inverted error function
        static qreal erfInv(qreal x);
        // Quantile function for the standard Gaussian law:
        // probability -> quantile
        static qreal phiInv(qreal p);
};
 
#endif // ELO_H