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

//-----------------------------------------------------------------------------
// eoReduceSplit.h
//   Base class for population-reducing classes - retaining the poor losers
// (c) GeNeura Team, 1998, Marc Schoenauer, 2002
/*
   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: Marc.Schoenauer@inria.fr
 */
//-----------------------------------------------------------------------------

#ifndef eoReduceSplit_h
#define eoReduceSplit_h

//-----------------------------------------------------------------------------

#include <iostream>

// EO includes
#include <eoPop.h>     // eoPop
#include <eoFunctor.h>  // eoReduce
#include <utils/selectors.h>

/** @addtogroup Replacors
 * @{
 */

/**
 * eoReduceSplit: reduce the pop to the specified size
 *                  AND eventually returns the eliminated guys
*/
template<class EOT> class eoReduceSplit: public eoBF<eoPop<EOT>&, eoPop<EOT> &, void >
{};

/** deterministic truncation method using sort */
template <class EOT>
class eoTruncateSplit : public eoReduceSplit<EOT>
{
public:
  /** Ctor: must provide amount of reduction,
      and whether or not you need to return the eliminated guys
  */
  eoTruncateSplit(eoHowMany _howMany, bool _returnEliminated = false):
    howMany(_howMany), returnEliminated(_returnEliminated) {}

  /** do the jonb */
  void operator()(eoPop<EOT>& _newgen, eoPop<EOT> & _eliminated)
  {
    unsigned popSize = _newgen.size();
    unsigned eliminated = howMany(popSize);
    if (!eliminated)   // nothing to do
      return ;
    unsigned newsize = popSize - eliminated;
    if (newsize < 0)
      throw std::logic_error("eoTruncateSplit: Cannot truncate to a larger size!\n");

    _newgen.nth_element(newsize);

    // save poor losers if necessary
    if (returnEliminated)
      for (unsigned i=0; i<eliminated; i++)
        _eliminated.push_back(_newgen[newsize+i]);
    // truncate
    _newgen.resize(newsize);
    return ;
  }

private:
  eoHowMany howMany;
  bool returnEliminated;
};

/** a ReduceSplit class that does not sort, but repeatidely kills the worse.
To be used in SSGA-like replacements (e.g. see eoSSGAWorseReplacement)
*/
template <class EOT>
class eoLinearTruncateSplit : public eoReduceSplit<EOT>
{
public:
  /** Ctor: must provide amount of reduction,
      and whether or not you need to return the eliminated guys
  */
  eoLinearTruncateSplit(eoHowMany _howMany, bool _returnEliminated = false):
    howMany(_howMany), returnEliminated(_returnEliminated) {}

  /** do the job */
  void operator()(eoPop<EOT>& _newgen, eoPop<EOT> & _eliminated)
  {
    unsigned popSize = _newgen.size();
    unsigned eliminated = howMany(popSize);
    if (!eliminated)   // nothing to do
      return ;
    long newsize = static_cast<long>(popSize) - static_cast<long>(eliminated);
    if (newsize < 0)
      throw std::logic_error("eoLinearTruncateSplit: Cannot truncate to a larger size!\n");

    _eliminated.reserve(_eliminated.size()+eliminated); //in case not empty?
    for (unsigned i=0; i<eliminated; i++)
      {
        typename eoPop<EOT>::iterator it = _newgen.it_worse_element();
        if (returnEliminated)
          _eliminated.push_back(*it);
        _newgen.erase(it);
      }
  }

private:
  eoHowMany howMany;
  bool returnEliminated;
};

/** random truncation - batch version */
template <class EOT>
class eoRandomSplit : public eoReduceSplit<EOT>
{
public:
  /** Ctor: must provide amount of reduction,
      and whether or not you need to return the eliminated guys
  */
  eoRandomSplit(eoHowMany _howMany, bool _returnEliminated = false):
    howMany(_howMany), returnEliminated(_returnEliminated) {}

  /** do the job */
  void operator()(eoPop<EOT>& _newgen, eoPop<EOT> & _eliminated)
  {
    unsigned popSize = _newgen.size();
    unsigned eliminated = howMany(popSize);
    if (!eliminated)   // nothing to do
      return ;
    unsigned newsize = popSize - eliminated;
    if (newsize < 0)
      throw std::logic_error("eoRandomSplit: Cannot truncate to a larger size!\n");

    _newgen.shuffle();

    // save poor losers if necessary
    if (returnEliminated)
      for (unsigned i=0; i<eliminated; i++)
        _eliminated.push_back(_newgen[newsize+i]);
    // truncate
    _newgen.resize(newsize);
    return ;
  }

private:
  eoHowMany howMany;
  bool returnEliminated;
};


/** random truncation - linear version */
template <class EOT>
class eoLinearRandomSplit : public eoReduceSplit<EOT>
{
public:
  /** Ctor: must provide amount of reduction,
      and whether or not you need to return the eliminated guys
  */
  eoLinearRandomSplit(eoHowMany _howMany, bool _returnEliminated = false):
    howMany(_howMany), returnEliminated(_returnEliminated) {}

  /** do the job */
  void operator()(eoPop<EOT>& _newgen, eoPop<EOT> & _eliminated)
  {
    unsigned popSize = _newgen.size();
    unsigned eliminated = howMany(popSize);
    if (!eliminated)   // nothing to do
      return ;
    unsigned newsize = popSize - eliminated;
    if (newsize < 0)
      throw std::logic_error("eoLinearRandomSplit: Cannot truncate to a larger size!\n");

    _eliminated.reserve(_eliminated.size()+eliminated); //in case not empty?
    for (unsigned i=0; i<eliminated; i++)
      {
        unsigned loser=random(_newgen.size());
        typename eoPop<EOT>::iterator it = _newgen.begin()+loser;
        if (returnEliminated)
          _eliminated.push_back(*it);
        _newgen.erase(it);
      }
    return ;
  }

private:
  eoHowMany howMany;
  bool returnEliminated;
};


/** a ReduceSplit class based on a repeated deterministic (reverse!) tournament
To be used in SSGA-like replacements (e.g. see eoSSGADetTournamentReplacement)
*/
template <class EOT>
class eoDetTournamentTruncateSplit : public eoReduceSplit<EOT>
{
public:
  /** Ctor: must provide amount of reduction,
      and whether or not you need to return the eliminated guys
  */
  eoDetTournamentTruncateSplit(unsigned _t_size, eoHowMany _howMany,
                      bool _returnEliminated = false):
    t_size(_t_size), howMany(_howMany),
    returnEliminated(_returnEliminated)
  {
    if (t_size < 2)
      {
          eo::log << eo::warnings << "Warning, Size for eoDetTournamentTruncateSplit adjusted to 2" << std::endl;
        t_size = 2;
      }
  }

  /** Performs repeated inverse_deterministic_tournament on the pop */
  void operator()(eoPop<EOT>& _newgen, eoPop<EOT> & _eliminated)
  // BUG???  void operator()(eoPop<EOT>& _newgen, unsigned _newsize)
  {
    unsigned popSize = _newgen.size();
    unsigned eliminated = howMany(popSize);
    if (!eliminated)   // nothing to do
      return ;
    unsigned newsize = popSize - eliminated;
    if (newsize < 0)
      throw std::logic_error("eoDetTournamentTruncateSplit: Cannot truncate to a larger size!\n");


    _eliminated.reserve(_eliminated.size()+eliminated); //in case not empty?
    for (unsigned i=0; i<eliminated; i++)
      {
        typename eoPop<EOT>::iterator it = inverse_deterministic_tournament(_newgen.begin(), _newgen.end(), t_size);
        if (returnEliminated)
          _eliminated.push_back(*it);
        _newgen.erase(it);
      }
  }

private:
  unsigned t_size;
  eoHowMany howMany;
  bool returnEliminated;
};

/** a ReduceSplit class based on a repeated deterministic (reverse!) tournament
To be used in SSGA-like replacements (e.g. see eoSSGAStochTournamentReplacement)
*/
template <class EOT>
class eoStochTournamentTruncateSplit : public eoReduce<EOT>
{
public:
  /** Ctor: must provide amount of reduction,
      and whether or not you need to return the eliminated guys
  */
  eoStochTournamentTruncateSplit(double _t_rate, eoHowMany _howMany,
                      bool _returnEliminated = false):
    t_rate(_t_rate), howMany(_howMany),
    returnEliminated(_returnEliminated)
  {
    if (t_rate <= 0.5)
      {
          eo::log << eo::warnings << "Warning, Rate for eoStochTournamentTruncateSplit adjusted to 0.51" << std::endl;
        t_rate = 0.51;
      }
    if (t_rate > 1)
      {
          eo::log << eo::warnings << "Warning, Rate for eoStochTournamentTruncateSplit adjusted to 1" << std::endl;
        t_rate = 1;
      }
  }

  /** Performs repeated inverse_stochastic_tournament on the pop */
  void operator()(eoPop<EOT>& _newgen, eoPop<EOT> & _eliminated)
  //BUG???  void operator()(eoPop<EOT>& _newgen, unsigned _newsize)
  {
    /* old version
    if (!_eliminated.size())       // nothing to do
      return;
    unsigned oldSize = _newgen.size();
    unsigned newSize = oldSize - _eliminated.size();
    unsigned eliminated = howMany(popSize);
    if (newSize < 0)
      throw std::logic_error("eoStochTournamentTruncateSplit: Cannot truncate to a larger size!\n");

end of old version    */

    unsigned popSize = _newgen.size();
    unsigned eliminated = howMany(popSize);
    if (!eliminated)   // nothing to do
      return ;
    unsigned newsize = popSize - eliminated;
    if (newsize < 0)
      throw std::logic_error("eoDetTournamentTruncateSplit: Cannot truncate to a larger size!\n");



    _eliminated.reserve(_eliminated.size()+eliminated); //in case not empty?
    for (unsigned i=0; i<_eliminated.size(); i++)
      {
        typename eoPop<EOT>::iterator it = inverse_stochastic_tournament(_newgen.begin(), _newgen.end(), t_rate);
        if (returnEliminated)
          _eliminated.push_back(*it);
        _newgen.erase(it);
      }
  }


private:
  double t_rate;
  eoHowMany howMany;
  bool returnEliminated;
};

//-----------------------------------------------------------------------------

/** @} */
#endif