eoStat.h

// -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-

//-----------------------------------------------------------------------------
// eoStat.h
// (c) Marc Schoenauer, Maarten Keijzer and GeNeura Team, 2000
/*
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Contact: todos@geneura.ugr.es, http://geneura.ugr.es
             Marc.Schoenauer@polytechnique.fr
             mkeijzer@dhi.dk
 */
//-----------------------------------------------------------------------------

#ifndef _eoStat_h
#define _eoStat_h

#include <numeric> // accumulate

#include <eoFunctor.h>
#include <utils/eoParam.h>
#include <eoPop.h>
#include <eoParetoFitness.h>

template <class EOT>
class eoStatBase : public eoUF<const eoPop<EOT>&, void>
{
public:
  virtual void lastCall(const eoPop<EOT>&) {}
  virtual std::string className(void) const { return "eoStatBase"; }
};

template <class EOT, class T>
class eoStat : public eoValueParam<T>, public eoStatBase<EOT>
{
public:

    eoStat(T _value, std::string _description)
        : eoValueParam<T>(_value, _description)
        {}

    virtual std::string className(void) const
        { return "eoStat"; }
};



template <class EOT>
class eoSortedStatBase : public eoUF<const std::vector<const EOT*>&, void>
{
public:
  virtual void lastCall(const std::vector<const EOT*>&) {}
  virtual std::string className(void) const { return "eoSortedStatBase"; }
};

template <class EOT, class ParamType>
class eoSortedStat : public eoSortedStatBase<EOT>, public eoValueParam<ParamType>
{
public :
  eoSortedStat(ParamType _value, std::string _desc) : eoValueParam<ParamType>(_value, _desc) {}
  virtual std::string className(void) const { return "eoSortedStat"; }
};

#ifdef _MSC_VER
template <class EOT> class eoAverageStat : public eoStat<EOT, EOT::Fitness>
#else
template <class EOT> class eoAverageStat : public eoStat<EOT, typename EOT::Fitness>
#endif
{
public :

    using eoStat<EOT, typename EOT::Fitness>::value;

    typedef typename EOT::Fitness Fitness;

    eoAverageStat(std::string _description = "Average Fitness")
      : eoStat<EOT, Fitness>(Fitness(), _description) {}

    static Fitness sumFitness(double _sum, const EOT& _eot){
        _sum += _eot.fitness();
        return _sum;
    }

    eoAverageStat(double _value, std::string _desc) : eoStat<EOT, double>(_value, _desc) {}

    virtual void operator()(const eoPop<EOT>& _pop){
      doit(_pop, Fitness()); // specializations for scalar and std::vector
    }

  virtual std::string className(void) const { return "eoAverageStat"; }

private :

    // Specialization for pareto fitness
    template <class T>
    void doit(const eoPop<EOT>& _pop, eoParetoFitness<T>)
    {
      value().clear();
      value().resize(_pop[0].fitness().size(), 0.0);

      for (unsigned o = 0; o < value().size(); ++o)
      {
        for (unsigned i = 0; i < _pop.size(); ++i)
        {
          value()[o] += _pop[i].fitness()[o];
        }

        value()[o] /= _pop.size();
      }
    }

    // Default behavior
    template <class T>
    void doit(const eoPop<EOT>& _pop, T)
    {
        Fitness v = std::accumulate(_pop.begin(), _pop.end(), Fitness(0.0), eoAverageStat::sumFitness);

        value() = v / _pop.size();
    }

};

template <class EOT>
class eoSecondMomentStats : public eoStat<EOT, std::pair<double, double> >
{
public :

    using eoStat<EOT, std::pair<double, double> >::value;

    typedef typename EOT::Fitness fitness_type;

    typedef std::pair<double, double> SquarePair;

    eoSecondMomentStats(std::string _description = "Average & Stdev")
        : eoStat<EOT, SquarePair>(std::make_pair(0.0,0.0), _description)
        {}

    static SquarePair sumOfSquares(SquarePair _sq, const EOT& _eo)
    {
        double fitness = _eo.fitness();

        _sq.first += fitness;
        _sq.second += fitness * fitness;
        return _sq;
    }

    virtual void operator()(const eoPop<EOT>& _pop)
    {
        SquarePair result = std::accumulate(_pop.begin(), _pop.end(), std::make_pair(0.0, 0.0), eoSecondMomentStats::sumOfSquares);

        double n = _pop.size();
        value().first = result.first / n; // average
        value().second = sqrt( (result.second - n * value().first * value().first) / (n - 1.0)); // stdev
    }

  virtual std::string className(void) const { return "eoSecondMomentStats"; }
};

#ifdef _MSC_VER
template <class EOT>
class eoNthElementFitnessStat : public eoSortedStat<EOT, EOT::Fitness >
#else
template <class EOT>
class eoNthElementFitnessStat : public eoSortedStat<EOT, typename EOT::Fitness >
#endif
{
public :
    using eoSortedStat<EOT, typename EOT::Fitness >::value;

    typedef typename EOT::Fitness Fitness;

    eoNthElementFitnessStat(unsigned _whichElement, std::string _description = "nth element fitness")
      : eoSortedStat<EOT, Fitness>(Fitness(), _description), whichElement(_whichElement) {}

    virtual void operator()(const std::vector<const EOT*>& _pop)
    {
        if (whichElement > _pop.size())
            throw std::logic_error("fitness requested of element outside of pop");

        doit(_pop, Fitness());
    }

  virtual std::string className(void) const { return "eoNthElementFitnessStat"; }
private :

    struct CmpFitness
    {
      CmpFitness(unsigned _whichElement, bool _maxim) : whichElement(_whichElement), maxim(_maxim) {}

      bool operator()(const EOT* a, const EOT* b)
      {
        if (maxim)
          return a->fitness()[whichElement] > b->fitness()[whichElement];

        return a->fitness()[whichElement] < b->fitness()[whichElement];
      }

      unsigned whichElement;
      bool maxim;
    };

    // Specialization for eoParetoFitness
    template <class T>
    void doit(const eoPop<EOT>& _pop, eoParetoFitness<T>)
    {
      typedef typename EOT::Fitness::fitness_traits traits;

      value().resize(traits::nObjectives());

      // copy of pointers, what the heck
      std::vector<const EOT*> tmp_pop = _pop;

      for (unsigned o = 0; o < value().size(); ++o)
      {
        typename std::vector<const EOT*>::iterator nth = tmp_pop.begin() + whichElement;
        std::nth_element(tmp_pop.begin(), nth, tmp_pop.end(), CmpFitness(o, traits::maximizing(o)));
        value()[o] = (*nth)->fitness()[o];
      }
    }

    // for everything else
    template <class T>
    void doit(const std::vector<const EOT*>& _pop, T)
    {
      value() = _pop[whichElement]->fitness();
    }

    unsigned whichElement;
};

/* Actually, you shouldn't need to sort the population to get the best fitness
   MS - 17/11/00

   But then again, if another stat needs sorted fitness anyway, getting the best
   out would be very fast.
   MK - 09/01/03

template <class EOT>
class eoBestFitnessStat : public eoStat<EOT, typename EOT::Fitness >
{
public :
    typedef typename EOT::Fitness Fitness;

    eoBestFitnessStat(std::string _description = "Best Fitness") :
      eoStat<EOT, Fitness>(Fitness(), _description) {}

    virtual void operator()(const eoPop<EOT>& _pop)
    {
        value() = _pop.nth_element_fitness(0);
    }

};
*/

#ifdef _MSC_VER
template <class EOT>
class eoBestFitnessStat : public eoStat<EOT, EOT::Fitness>
#else
template <class EOT>
class eoBestFitnessStat : public eoStat<EOT, typename EOT::Fitness>
#endif
{
public:

    using eoStat<EOT, typename EOT::Fitness>::value;

    typedef typename EOT::Fitness Fitness;

    eoBestFitnessStat(std::string _description = "Best ")
        : eoStat<EOT, Fitness>(Fitness(), _description)
        {}

    void operator()(const eoPop<EOT>& _pop) {
        doit(_pop, Fitness() ); // specializations for scalar and std::vector
    }

    virtual std::string className(void) const { return "eoBestFitnessStat"; }


private :

    struct CmpFitness
    {
      CmpFitness(unsigned _which, bool _maxim) : which(_which), maxim(_maxim) {}

      bool operator()(const EOT& a, const EOT& b)
      {
        if (maxim)
          return a.fitness()[which] < b.fitness()[which];

        return a.fitness()[which] > b.fitness()[which];
      }

      unsigned which;
      bool maxim;
    };

    // Specialization for pareto fitness
    template <class T>
    void doit(const eoPop<EOT>& _pop, eoParetoFitness<T>)
    {
      typedef typename EOT::Fitness::fitness_traits traits;
      value().resize(traits::nObjectives());

      for (unsigned o = 0; o < traits::nObjectives(); ++o)
      {
        typename eoPop<EOT>::const_iterator it = std::max_element(_pop.begin(), _pop.end(), CmpFitness(o, traits::maximizing(o)));
        value()[o] = it->fitness()[o];
      }
    }

    // default
    template<class T>
    void doit(const eoPop<EOT>& _pop, T)
    { // find the largest elements
      value() = _pop.best_element().fitness();
    }

};

template <class EOT>
class eoDistanceStat : public eoStat<EOT, double>
{
public:

    using eoDistanceStat< EOT >::value;

    eoDistanceStat(std::string _name = "distance")
        : eoStat<EOT, double>(0.0, _name)
        {}

    template <class T>
    double distance(T a, T b)
    {
        T res = a-b;
        return res < 0? -res : res;
    }

    double distance(bool a, bool b)
    {
        return (a==b)? 0 : 1;
    }

    void operator()(const eoPop<EOT>& _pop)
    {
        double& v = value();
        v = 0.0;

        for (unsigned i = 0; i < _pop.size(); ++i)
        {
            for (unsigned j = 0; j < _pop.size(); ++j)
            {
                for (unsigned k = 0; k < _pop[i].size(); ++k)
                {
                    v += distance(_pop[i][k], _pop[j][k]);
                }
            }
        }

        double sz = _pop.size();
        v /= sz * sz * _pop[0].size();
    }
  virtual std::string className(void) const { return "eoDistanceStat"; }

};



/*
template <class EOT>
class eoStdevStat : public eoStat<EOT, double >
{
public :
    typedef typename eoSecondMomentStats<EOT>::SquarePair SquarePair;

    eoStdevStat(std::string _description = "Stdev") : eoStat<EOT, double>(0.0, _description) {}

    virtual void operator()(const eoPop<EOT>& _pop)
    {
        SquarePair result = std::accumulate(pop.begin(), pop.end(), std::make_pair(0.0, 0.0), eoSecondMomentStats::sumOfSquares);

        double n = pop.size();
        value() = sqrt( (result.second - (result.first / n)) / (n - 1.0)); // stdev
    }
};
*/
#endif

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