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

// "moSA.h"

// (c) OPAC Team, LIFL, 2003-2006

/* LICENCE TEXT
   
   Contact: paradiseo-help@lists.gforge.inria.fr
*/

#ifndef __moSA_h
#define __moSA_h

#include <unistd.h>

#include <eoOp.h>
#include <eoEvalFunc.h>

#include "moAlgo.h"
#include "moRandMove.h"
#include "moMoveIncrEval.h"
#include "moCoolingSchedule.h"
#include "moSolContinue.h"

#include <math.h>

//! Simulated Annealing (SA)
/*!
  Class that describes a Simulated Annealing algorithm.
*/
template < class M > class moSA:public moAlgo < typename M::EOType >
{

  //! Alias for the type
  typedef
    typename
    M::EOType
    EOT;

  //! Alias for the fitness
  typedef
    typename
    EOT::Fitness
    Fitness;

public:

  //! SA constructor
  /*!
     All the boxes used by a SA need to be given.

     \param __move_rand a move generator (generally randomly).
     \param __incr_eval a (generaly) efficient evaluation function 
     \param __cont a stopping criterion.
     \param __init_temp the initial temperature.
     \param __cool_sched a cooling schedule, describes how the temperature is modified.
     \param __full_eval a full evaluation function.
   */
  moSA (moRandMove < M > &__move_rand,
	moMoveIncrEval < M > &__incr_eval,
	moSolContinue < EOT > &__cont,
	double __init_temp,
	moCoolingSchedule & __cool_sched, eoEvalFunc < EOT > &__full_eval):
  move_rand (__move_rand),
  incr_eval (__incr_eval),
  cont (__cont),
  init_temp (__init_temp),
  cool_sched (__cool_sched),
  full_eval (__full_eval)
  {

  }

  //! function that launches the SA algorithm.
  /*!
     As a moTS or a moHC, the SA can be used for HYBRIDATION in an evolutionary algorithm.

     \param __sol a solution to improve.
     \return TRUE.
   */
  bool operator   ()(EOT & __sol)
  {

    if (__sol.invalid ())
      {
	full_eval (__sol);
      }

    double
      temp = init_temp;

    M move;

    EOT best_sol = __sol;

    do
      {

	cont.init ();
	do
	  {

	    move_rand (move);

	    Fitness delta_fit = incr_eval (move, __sol) - __sol.fitness ();

	    if (delta_fit > 0 || rng.uniform () < exp (delta_fit / temp))
	      {

		__sol.fitness (incr_eval (move, __sol));
		move (__sol);

		/* Updating the best solution found
		   until now ? */
		if (__sol.fitness () > best_sol.fitness ())
		  best_sol = __sol;
	      }

	  }
	while (cont (__sol));

      }
    while (cool_sched (temp));

    __sol = best_sol;

    return true;
  }

private:

  //! A move generator (generally randomly)
  moRandMove < M > &move_rand;

  //! A (generally) efficient evaluation function.
  moMoveIncrEval < M > &incr_eval;

  //! Stopping criterion before temperature update
  moSolContinue < EOT > &cont;

  //! Initial temperature
  double
    init_temp;

  //! The cooling schedule
  moCoolingSchedule & cool_sched;

  //! A full evaluation function.
  eoEvalFunc < EOT > &full_eval;	// Full evaluator.
};

#endif