UnityScaler.h

#ifndef _theplu_yat_normalizer_unity_scaler_
#define _theplu_yat_normalizer_unity_scaler_

// $Id: UnityScaler.h 4164 2022-03-13 22:47:56Z peter $

/*
  Copyright (C) 2020, 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 "RangeNormalizer.h"
#include "yat/statistics/AveragerWeighted.h"
#include "yat/utility/DataIterator.h"

#include <functional>
#include <numeric>

namespace theplu {
namespace yat {
namespace normalizer {

  namespace detail {
    class UnityScalerFactor
    {
    public:
      // return the inverse of the sum of range [first, last)
      template<typename Iterator>
      double operator()(Iterator first, Iterator last) const
      {
        using traits = typename utility::weighted_iterator_traits<Iterator>;
        return calculate(first, last, typename traits::type());
      }

    private:

      template<typename Iterator>
      double calculate(Iterator first, Iterator last,
                       utility::unweighted_iterator_tag tag) const
      {
        return 1.0 / std::accumulate(utility::data_iterator(first),
                                     utility::data_iterator(last),
                                     0.0);
      }


      template<typename Iterator>
      double calculate(Iterator first, Iterator last,
                       utility::weighted_iterator_tag tag) const
      {
        statistics::AveragerWeighted averager;
        add(averager, first, last);
        return 1.0 / averager.sum_wx();
      }
    };
  }


  using UnityScaler =
    RangeNormalizer<detail::UnityScalerFactor, std::multiplies<double>>;

}}} // end of namespace normalizer, yat and thep
#endif