git-svn-id: svn://scm.gforge.inria.fr/svnroot/paradiseo@34 331e1502-861f-0410-8da2-ba01fb791d7f

trunk/paradiseo-mo/src/moRandImprSelect.h

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+// -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
+
+// "moRandImprSelect.h"
+
+// (c) OPAC Team, LIFL, 2003-2006
+
+/* LICENCE TEXT
+   
+   Contact: paradiseo-help@lists.gforge.inria.fr
+*/
+
+#ifndef __moRandImprSelect_h
+#define __moRandImprSelect_h
+
+#include <vector>
+
+#include <utils/eoRNG.h>
+#include "moMoveSelect.h"
+
+//! One of the possible moMove selector (moMoveSelect)
+/*!
+  All the neighbors are considered. 
+  One of them that enables an improvment of the objective function is choosen.
+*/
+template < class M > class moRandImprSelect:public moMoveSelect < M >
+{
+
+public:
+
+  //! Alias for the fitness
+  typedef typename M::EOType::Fitness Fitness;
+
+  //!Procedure which all that needs a moRandImprSelect
+  /*!
+     Give a value to the initialise fitness.
+     Clean the move and fitness vectors.
+
+     \param __fit the current best fitness
+   */
+  void init (const Fitness & __fit)
+  {
+    init_fit = __fit;
+    vect_better_fit.clear ();
+    vect_better_moves.clear ();
+  }
+
+  //! Function that updates the fitness and move vectors
+  /*!
+     if a move give a better fitness than the initial fitness, 
+     it is saved and the fitness too.
+
+     \param __move a new move.
+     \param __fit a new fitness associated to the new move.
+     \return TRUE.
+   */
+  bool update (const M & __move, const Fitness & __fit)
+  {
+
+    if (__fit > init_fit)
+      {
+
+	vect_better_fit.push_back (__fit);
+	vect_better_moves.push_back (__move);
+      }
+
+    return true;
+  }
+
+  //! The move selection
+  /*!
+     One the saved move is randomly chosen.
+
+     \param __move the reference of the move that can be initialised by the function.
+     \param __fit the reference of the fitness that can be initialised by the function.
+     \throws EmptySelection If no move which improves the current fitness are found.
+   */
+  void operator   () (M & __move, Fitness & __fit) throw (EmptySelection)
+  {
+
+    if (!vect_better_fit.empty ())
+      {
+
+	unsigned n = rng.random (vect_better_fit.size ());
+
+	__move = vect_better_moves[n];
+	__fit = vect_better_fit[n];
+      }
+    else
+      throw EmptySelection ();
+  }
+
+private:
+
+  //! Fitness of the current solution.
+  Fitness init_fit;
+
+  //! Candidate fitnesse vector.
+  std::vector < Fitness > vect_better_fit;
+
+  //! Candidate move vector.
+  std::vector < M > vect_better_moves;
+};
+
+#endif