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

// "TwoOptIncrEval.cpp"

// (c) OPAC Team, LIFL, 2003

/* 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: cahon@lifl.fr
*/

#include "two_opt_incr_eval.h"
#include "graph.h"

float TwoOptIncrEval :: operator () (const TwoOpt & __move, const Route & __route) {
  
  // From
  unsigned v1 = __route [__move.first], v1_next = __route [__move.first + 1] ;
  
  // To
  unsigned v2 = __route [__move.second], v2_next = __route [__move.second + 1] ;
  
  return __route.fitness () - Graph :: distance (v1, v2) - Graph :: distance (v1_next, v2_next) + Graph :: distance (v1, v1_next) + Graph :: distance (v2, v2_next)  ;
}