Chi2.h

#ifndef _theplu_yat_statistics_chi2_
#define _theplu_yat_statistics_chi2_

// $Id: Chi2.h 4207 2022-08-26 04:36:28Z peter $

/*
  Copyright (C) 2018, 2022 Peter Johansson

  This file is part of the yat library, http://dev.thep.lu.se/yat

  The yat library 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.

  The yat 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
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with yat. If not, see <http://www.gnu.org/licenses/>.
*/

#include <yat/utility/Matrix.h>

namespace theplu {
namespace yat {
namespace statistics {

  class Chi2
  {
  public:
    unsigned int dof(void) const;

    const utility::Matrix& expected(void) const;

    double p_value(void) const;

    double p_value(size_t N) const;

    double operator()(void);

    double operator()(const utility::MatrixBase& data);

  private:
    double chi2_;
    utility::Matrix expected_;
    utility::Vector rowsum_;
    utility::Vector colsum_;
    unsigned long int total_;

    void calculate_expected(const utility::MatrixBase& data);
    void calculate_rowsum(const utility::MatrixBase& data);
    void calculate_colsum(const utility::MatrixBase& data);

    // Create a matrix with non-negative integers such that the sum of
    // row r is rowsum_(r) and sum of column c is colsum_(c)
    utility::Matrix generate_random_data(void) const;

    double chi2sum(const utility::MatrixBase& data,
                   const utility::Matrix& expected) const;

    size_t draw(const utility::Vector& count, unsigned long int N) const;

    struct Calculator
    {
      double operator()(double x, double m) const;
    };
  };

}}} // of namespace statistics, yat, and theplu

#endif