/*-------------------------------------------------------------------------------------*/
/*  NOMAD - Nonlinear Optimization by Mesh Adaptive Direct search - version 3.6.1        */
/*                                                                                     */
/*  Copyright (C) 2001-2012  Mark Abramson        - the Boeing Company, Seattle        */
/*                           Charles Audet        - Ecole Polytechnique, Montreal      */
/*                           Gilles Couture       - Ecole Polytechnique, Montreal      */
/*                           John Dennis          - Rice University, Houston           */
/*                           Sebastien Le Digabel - Ecole Polytechnique, Montreal      */
/*                           Christophe Tribes    - Ecole Polytechnique, Montreal      */
/*                                                                                     */
/*  funded in part by AFOSR and Exxon Mobil                                            */
/*                                                                                     */
/*  Author: Sebastien Le Digabel                                                       */
/*                                                                                     */
/*  Contact information:                                                               */
/*    Ecole Polytechnique de Montreal - GERAD                                          */
/*    C.P. 6079, Succ. Centre-ville, Montreal (Quebec) H3C 3A7 Canada                  */
/*    e-mail: nomad@gerad.ca                                                           */
/*    phone : 1-514-340-6053 #6928                                                     */
/*    fax   : 1-514-340-5665                                                           */
/*                                                                                     */
/*  This program 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 3 of the License, or (at your option) any later         */
/*  version.                                                                           */
/*                                                                                     */
/*  This program 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 program. If not, see <http://www.gnu.org/licenses/>.                     */
/*                                                                                     */
/*  You can find information on the NOMAD software at www.gerad.ca/nomad               */
/*-------------------------------------------------------------------------------------*/
/**
  \file   Speculative_Search.cpp
  \brief  Speculative search (implementation)
  \author Sebastien Le Digabel
  \date   2010-04-12
  \see    Speculative.hpp
*/
#include "Speculative_Search.hpp"

/*-------------------------------------------------------------*/
/*                     MADS speculative search                 */
/*-------------------------------------------------------------*/
/*  x_k = x_{k-1} + \Delta^m_{k-1} d                           */
/*  s_k = x_{k-1} +        \Delta^m_k d  if l_{k-1} > 0        */
/*    or  x_{k-1} + \tau * \Delta^m_k d  otherwise             */
/*-------------------------------------------------------------*/
/*  the directions that we use already contain \Delta^m:       */
/*     dir = \Delta^m_{k-1} d                                  */
/*-------------------------------------------------------------*/
/*  the test ' if (new_feas_inc || new_infeas_inc ) ' is true  */
/*  and has already been made in Mads.cpp                      */
/*-------------------------------------------------------------*/
void NOMAD::Speculative_Search::search ( NOMAD::Mads              & mads           ,
					 int                      & nb_search_pts  ,
					 bool                     & stop           ,
					 NOMAD::stop_type         & stop_reason    ,
					 NOMAD::success_type      & success        ,
					 bool                     & count_search   ,
					 const NOMAD::Eval_Point *& new_feas_inc   ,
					 const NOMAD::Eval_Point *& new_infeas_inc   )
{
  // new_feas_inc and new_infeas_inc are used as inputs,
  // so do not initialize them to NULL here

  nb_search_pts = 0;
  success       = NOMAD::UNSUCCESSFUL;
  count_search  = !stop;

  if ( stop )
    return;
  
  const NOMAD::Display    & out = _p.out();
  NOMAD::dd_type display_degree = out.get_search_dd();
  if ( display_degree == NOMAD::FULL_DISPLAY ) {
    std::ostringstream oss;
    oss << NOMAD::SPEC_SEARCH;
    out << std::endl << NOMAD::open_block ( oss.str() ) << std::endl;
  }

  int                       lkm1;  // l_{k-1}
  int                       lk;    // l_k
  int                       n;
  NOMAD::Signature        * signature;
  NOMAD::Point              delta_m_k;
  NOMAD::Point              delta_m_km1;
  NOMAD::Point              factor;
  NOMAD::Point              xkm1;
  NOMAD::Eval_Point       * sk;
  const NOMAD::Eval_Point * x[2];
  x[0] = new_feas_inc;
  x[1] = new_infeas_inc;
  
  // Evaluator_Control:
  NOMAD::Evaluator_Control & ev_control = mads.get_evaluator_control();

  for ( int i = 0 ; i < 2 ; ++i ) {    
    if ( x[i] && x[i]->get_mesh_index() ) {

      const NOMAD::Direction * dir = x[i]->get_direction();
      if ( dir && ( dir->is_mads() || dir->get_type()==NOMAD::MODEL_SEARCH_DIR ) ) {

	// get the x_k's signature:
	signature = x[i]->get_signature();
	if ( !signature )
	  throw NOMAD::Exception ( "Speculative_Search.cpp" , __LINE__ ,
	  "Speculative_Search::search(): could not get the signature" );
      
	xkm1 = *x[i] - *dir;
      
	lk = lkm1 = *x[i]->get_mesh_index();
	NOMAD::Mesh::update ( NOMAD::FULL_SUCCESS , lk );
      
	n           = signature->get_n();
	delta_m_k   = NOMAD::Point ( n );
	delta_m_km1 = NOMAD::Point ( n );
	factor      = NOMAD::Point ( n );

	signature->get_mesh().get_delta_m ( delta_m_k   , lk   );
	signature->get_mesh().get_delta_m ( delta_m_km1 , lkm1 );
      
	// multiplicative factor: takes into account the fact that
	// the direction contains \Delta^m_k:
	try {

	  // factor = delta_m_k / delta_m_km1 :
	  for ( int k = 0 ; k < n ; ++k ) {
	    if ( delta_m_k[k].is_defined()   && delta_m_km1[k].is_defined() &&
		 delta_m_k[k].value() != 0.0 && delta_m_km1[k].value() != 0.0 )
	      factor[k] = delta_m_k[k] / delta_m_km1[k];
	    else
	      factor[k] = 0.0;
	  }
	}
	catch ( NOMAD::Double::Invalid_Value & ) {
	  if ( display_degree == NOMAD::FULL_DISPLAY )
	    out << "could not compute " << _type << " point: stop" << std::endl
		<< NOMAD::close_block ( "end of speculative search" );
	  stop        = true;
	  stop_reason = NOMAD::MESH_PREC_REACHED;
	  return;
	}
      
	if ( lkm1 <= 0 )
	  factor *= NOMAD::Mesh::get_mesh_update_basis();
      
	// speculative search point:
	NOMAD::Direction new_dir ( n , 0.0 , dir->get_type() );
	new_dir.Point::operator = ( factor * *dir );
      
	sk = new NOMAD::Eval_Point;
	sk->set ( n , _p.get_bb_nb_outputs() );
	sk->set_signature  ( signature );
	sk->set_direction  ( &new_dir );
	sk->set_mesh_index ( &lk );
      
	sk->Point::operator = ( xkm1 + new_dir );

	if ( display_degree == NOMAD::FULL_DISPLAY ) {
	  out << "trial point #" << sk->get_tag()
	      << ": ( ";
	  sk->Point::display ( out ," " , 2 , NOMAD::Point::get_display_limit() );
	  out << " )" << std::endl;
	}
      
	// add the new point to the list of search trial points:
	ev_control.add_eval_point ( sk                      ,
				    display_degree          ,
				    _p.get_snap_to_bounds() ,
				    NOMAD::Double()         ,
				    NOMAD::Double()         ,
				    NOMAD::Double()         ,
				    NOMAD::Double()           );
      }
    }
  }
  
  nb_search_pts = ev_control.get_nb_eval_points();
  
  // eval_list_of_points:
  // --------------------
  new_feas_inc = new_infeas_inc = NULL;

  ev_control.eval_list_of_points ( _type                   ,
				   mads.get_true_barrier() ,
				   mads.get_sgte_barrier() ,
				   mads.get_pareto_front() ,
				   stop                    ,
				   stop_reason             ,
				   new_feas_inc            ,
				   new_infeas_inc          ,
				   success                   );

  if ( display_degree == NOMAD::FULL_DISPLAY ) {
    std::ostringstream oss;
    oss << "end of speculative search (" << success << ")";
    out << NOMAD::close_block ( oss.str() ) << std::endl;
  }
}
