/*

* This file is part of the GreasePad distribution (https://github.com/FraunhoferIOSB/GreasePad).

* Copyright (c) 2022-2026 Jochen Meidow, Fraunhofer IOSB

*

* 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 3 of the License, or

* (at your option) any later version.

*

* This program 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 this program. If not, see <https://www.gnu.org/licenses/>.

*/

#ifndef QUANTILES_H

#define QUANTILES_H

#include "statistics/chisquared.h"

#include "statistics/exponential.h"

#include "statistics/normal.h"

#include "statistics/prob.h"

//! Quantiles for recognition and snapping

namespace Quantiles {

//! Quantiles for snapping of end-points

struct Snapping

{

public:

//! Get quantile of standard normal distribution

[[nodiscard]] double quantile_stdNormDistr() const { return quantile_snd_; }

//! Get quantile of chi-square distribution with two degree of freedom

[[nodiscard]] double quantile_chi2_1dof() const { return quantile_chi2_1_; }

//! Set significance level alpha

void setAlpha( Stats::Prob alpha ) {

quantile_snd_ = Stats::StandardNormal::icdf( alpha.complement() );

quantile_chi2_1_ = distr_chi2_1_.icdf( alpha.complement() );

}

private:

double quantile_snd_{}; // Quantile of standard normal distribution N(0,1)

double quantile_chi2_1_{}; // Quantile of chi-squared distribution with 1 degree of freedom

const Stats::ChiSquared distr_chi2_1_{1};

// const Stats::StandardNormal distr_snd_;

};

//! Quantiles for recognition of geometric relations

struct Recognition

{

public:

//! Get quantile of chi-square distribution with one degree of freedom

[[nodiscard]] double quantile_chi2_1dof() const { return quantile_chi2_1dof_; }

//! Get quantile of chi-square distribution with two degree of freedom

[[nodiscard]] double quantile_chi2_2dof() const { return quantile_chi2_2dof_; }

//! Set significance level alpha

void setAlpha( Stats::Prob alpha ) {

quantile_chi2_1dof_ = distr_chi2_1_.icdf( alpha.complement() );

quantile_chi2_2dof_ = distr_Exp_0p5_.icdf( alpha.complement() );

}

private:

double quantile_chi2_1dof_{};

double quantile_chi2_2dof_{};

const Stats::ChiSquared distr_chi2_1_{1};

const Stats::Exponential distr_Exp_0p5_{0.5};

};

} // namespace Quantiles

#endif // QUANTILES_H