/*
  <moDistanceStat.h>
  Copyright (C) DOLPHIN Project-Team, INRIA Lille - Nord Europe, 2006-2010

  Sébastien Verel, Arnaud Liefooghe, Jérémie Humeau

  This software is governed by the CeCILL license under French law and
  abiding by the rules of distribution of free software.  You can  use,
  modify and/ or redistribute the software under the terms of the CeCILL
  license as circulated by CEA, CNRS and INRIA at the following URL
  "http://www.cecill.info".

  As a counterpart to the access to the source code and  rights to copy,
  modify and redistribute granted by the license, users are provided only
  with a limited warranty  and the software's author,  the holder of the
  economic rights,  and the successive licensors  have only  limited liability.

  In this respect, the user's attention is drawn to the risks associated
  with loading,  using,  modifying and/or developing or reproducing the
  software by the user in light of its specific status of free software,
  that may mean  that it is complicated to manipulate,  and  that  also
  therefore means  that it is reserved for developers  and  experienced
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  encouraged to load and test the software's suitability as regards their
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  The fact that you are presently reading this means that you have had
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  ParadisEO WebSite : http://paradiseo.gforge.inria.fr
  Contact: paradiseo-help@lists.gforge.inria.fr
*/

#ifndef moDistanceStat_h
#define moDistanceStat_h

#include <utils/eoDistance.h>
#include <continuator/moStat.h>

/**
 * The statistic gives the distance to a reference solution
 * The reference solution could be the global optimum, or the best knowed solution
 * It allows to compute the Fitness-Distance correlation (FDC)
 */
template <class EOT, class T = double>
class moDistanceStat : public moStat<EOT, T>
{
public :
    using moStat< EOT, T >::value;

    /**
     * Constructor
     * @param _dist a distance
     * @param _ref the reference solution
     */
    moDistanceStat(eoDistance<EOT> & _dist, EOT & _ref): moStat<EOT, T>(0, "distance"), dist(_dist), refSolution(_ref) {}

    /**
     * Compute distance between the first solution and the reference solution
     * @param _sol the first solution
     */
    virtual void init(EOT & _sol) {
        value() = dist(_sol, refSolution);
    }

    /**
     * Compute distance between a solution and the reference solution
     * @param _sol a solution
     */
    virtual void operator()(EOT & _sol) {
        value() = dist(_sol, refSolution);
    }

    /**
     * @return name of the class
     */
    virtual std::string className(void) const {
        return "moDistanceStat";
    }

private:
    /** the distance */
    eoDistance<EOT> & dist;
    /**
     * the reference solution does not change during the run
     * it could be the best solution knowed of the problem
     */
    EOT refSolution;

};

#endif