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

//-----------------------------------------------------------------------------
// eoRandomSelect.h
// (c) GeNeura Team, 1998 - EEAAX 1999, Maarten Keijzer 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
             mak@dhi.dk
 */
//-----------------------------------------------------------------------------

#ifndef eoRandomSelect_h
#define eoRandomSelect_h

//-----------------------------------------------------------------------------
/** This file contains straightforward selectors:
 * eoRandomSelect          returns an individual uniformly selected
 * eoBestSelect            always return the best individual
 * eoSequentialSelect      returns all individuals in turn
 */

#include <utils/eoRNG.h>
#include <eoSelectOne.h>

//-----------------------------------------------------------------------------
/** eoRandomSelect: a selection method that selects ONE individual randomly */
//-----------------------------------------------------------------------------

template <class EOT> class eoRandomSelect: public eoSelectOne<EOT>
{
 public:

  /// not a big deal!!!
  virtual const EOT& operator()(const eoPop<EOT>& _pop)
  {
    return _pop[eo::rng.random(_pop.size())] ;
  }
};

//-----------------------------------------------------------------------------
/** eoBestSelect: a selection method that always return the best
 *                (mainly for testing purposes) */
//-----------------------------------------------------------------------------

template <class EOT> class eoBestSelect: public eoSelectOne<EOT>
{
 public:

  /// not a big deal!!!
  virtual const EOT& operator()(const eoPop<EOT>& _pop)
  {
    return _pop.best_element() ;
  }
};

//-----------------------------------------------------------------------------
/** eoSequentialSelect: returns all individual in order
 *       looping back to the beginning when exhasuted
 * can be from best to worse, or in random order
 *
 * It is the eoSelectOne equivalent of eoDetSelect -
 *    though eoDetSelect always returns individuals from best to worst
 */
//-----------------------------------------------------------------------------

template <class EOT> class eoSequentialSelect: public eoSelectOne<EOT>
{
 public:
  /** Ctor: sets the current pter to MAXINT so init will take place first time
      not very elegant, maybe ...
  */
  eoSequentialSelect(bool _ordered = true):
    ordered(_ordered), current(MAXINT) {}

  void setup(const eoPop<EOT>& _pop)
  {
    eoPters.resize(_pop.size());
    if (ordered)    // probably we could have a marker to avoid re-sorting
	    _pop.sort(eoPters);
    else
      _pop.shuffle(eoPters);
    current=0;
  }

  virtual const EOT& operator()(const eoPop<EOT>& _pop)
  {
    if (current >= _pop.size())
      setup(_pop);

    unsigned eoN = current;
    current++;
    return *eoPters[eoN] ;
  }
private:
  bool ordered;
  unsigned current;
  vector<const EOT*> eoPters;
};

#endif eoRandomSelect_h