source: trunk/yat/normalizer/Centralizer.h @ 2146

#ifndef _theplu_yat_normalizer_centralizer_
#define _theplu_yat_normalizer_centralizer_

// $Id: Centralizer.h 2146 2010-01-15 23:32:09Z peter $

/*
  Copyright (C) 2008 Jari Häkkinen, Peter Johansson
  Copyright (C) 2009 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/statistics/Average.h"
#include "yat/utility/DataIterator.h"
#include "yat/utility/iterator_traits.h"
#include "yat/utility/WeightIterator.h"

#include <boost/concept_check.hpp>

#include <algorithm>
#include <functional>

namespace theplu {
namespace yat {
namespace normalizer {

  /**
     \brief Centralize a range

     The center is calculated and then that value is subtracted from
     each element. By default the center is defined as the arithmetic
     mean, but this can be changed by providing a suitable
     UnaryFunction.

     \since New in yat 0.5
   */
  template<class UnaryFunction = statistics::Average>
  class Centralizer
  {
  public:
    /**
       \brief default constructor

       Internal UnaryFunction is created using its default
       constructor.
     */
    Centralizer(void){}

    /**
       \param uf unary function defining the center.
     */
    Centralizer(const UnaryFunction& uf)
      : func_(uf) {}

    /**
       Calculates the center \a c of the range [first, last) using
       UnaryFunction. This value, \a c, is then subtracted from each
       element in the range [first, last) and assigned to the
       corresponding element in range [result, result + (last-first) ).

       It is possible to centralize a range "in place"; it is
       permissible for the iterators \a first and \a result to be the
       same. 

       \see std::transform
     */
    template<class InputIterator, class OutputIterator>
    void operator()(InputIterator first, InputIterator last,
                    OutputIterator result) const
    {
      boost::function_requires<boost::InputIterator<InputIterator> >();
      typename utility::weighted_iterator_traits<InputIterator>::type tag;
      normalize(first, last, result, tag);
    }

  private:
    UnaryFunction func_;

    // unweighted version
    template<class InputIterator, class OutputIterator>
    void normalize(InputIterator first,InputIterator last,OutputIterator result,
                   utility::unweighted_iterator_tag tag) const
    {
      std::transform(first, last, result, 
                     std::bind2nd(std::minus<double>(), func_(first, last)));
    }


    // weighted version
    template<class InputIterator, class OutputIterator>
    void normalize(InputIterator first,InputIterator last,OutputIterator result,
                   utility::weighted_iterator_tag tag) const
    {
      std::copy(utility::weight_iterator(first), 
                utility::weight_iterator(last), 
                utility::weight_iterator(result));
      std::transform(utility::data_iterator(first), 
                     utility::data_iterator(last), 
                     utility::data_iterator(result),
                     std::bind2nd(std::minus<double>(),func_(first, last)));
    }

  };

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