Refactoring and sanitization of the Metropolis-Hastings-related algorithms for more modularity/flexibility

mo/src/explorer/moSimpleMetropolisHastingsExplorer.h

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+/*
+  <moSimpleMetropolisHastingsExplorer.h>
+  Copyright (C) DOLPHIN Project-Team, INRIA Lille - Nord Europe, 2006-2010
+
+  Sébastien Verel, Arnaud Liefooghe, Jérémie Humeau, Lionel Parreaux
+
+  This software is governed by the CeCILL license under French law and
+  abiding by the rules of distribution of free software.  You can  use,
+  modify and/ or redistribute the software under the terms of the CeCILL
+  license as circulated by CEA, CNRS and INRIA at the following URL
+  "http://www.cecill.info".
+
+  As a counterpart to the access to the source code and  rights to copy,
+  modify and redistribute granted by the license, users are provided only
+  with a limited warranty  and the software's author,  the holder of the
+  economic rights,  and the successive licensors  have only  limited liability.
+
+  In this respect, the user's attention is drawn to the risks associated
+  with loading,  using,  modifying and/or developing or reproducing the
+  software by the user in light of its specific status of free software,
+  that may mean  that it is complicated to manipulate,  and  that  also
+  therefore means  that it is reserved for developers  and  experienced
+  professionals having in-depth computer knowledge. Users are therefore
+  encouraged to load and test the software's suitability as regards their
+  requirements in conditions enabling the security of their systems and/or
+  data to be ensured and,  more generally, to use and operate it in the
+  same conditions as regards security.
+  The fact that you are presently reading this means that you have had
+  knowledge of the CeCILL license and that you accept its terms.
+
+  ParadisEO WebSite : http://paradiseo.gforge.inria.fr
+  Contact: paradiseo-help@lists.gforge.inria.fr
+*/
+
+#ifndef _moSimpleMetropolisHastingsExplorer_h
+#define _moSimpleMetropolisHastingsExplorer_h
+/*
+#include <cstdlib>
+
+#include <explorer/moNeighborhoodExplorer.h>
+#include <comparator/moNeighborComparator.h>
+#include <comparator/moSolNeighborComparator.h>
+#include <neighborhood/moNeighborhood.h>
+
+#include <utils/eoRNG.h>*/
+#include <explorer/moMetropolisHastingsExplorer.h>
+
+
+/**
+ * Explorer for the Metropolis-Hasting Sampling.
+ * Only the symetric case is considered when Q(x,y) = Q(y,x)
+ * Fitness must be > 0
+ */
+template< class Neighbor >
+class moSimpleMetropolisHastingsExplorer
+: public moMetropolisHastingsExplorer< Neighbor, moSimpleMetropolisHastingsExplorer<Neighbor> >
+{
+public:
+    typedef typename Neighbor::EOT EOT ;
+    typedef moNeighborhood<Neighbor> Neighborhood ;
+    
+    using moNeighborhoodExplorer<Neighbor>::selectedNeighbor;
+    
+    /**
+     * Constructor for the simple MH explorer
+     * @param _neighborhood the neighborhood
+     * @param _eval the evaluation function
+     * @param _maxSteps maximum number of currentStepNb to do
+     * @param _solNeighborComparator a solution vs neighbor comparator
+     */
+    moSimpleMetropolisHastingsExplorer (
+        Neighborhood& _neighborhood,
+        moEval<Neighbor>& _eval,
+        unsigned int _maxSteps,
+        eoOptional< moSolNeighborComparator<Neighbor> > _comp = NULL
+    )
+    : moMetropolisHastingsExplorer< Neighbor, moSimpleMetropolisHastingsExplorer<Neighbor> >(_neighborhood, _eval, _comp)
+    , maxSteps(_maxSteps)
+    { }
+    
+    /**
+     * initialization of currentStepNb to be done here
+     * @param _solution unused
+     */
+    virtual void initParam(EOT & _solution) {
+        currentStepNb = 0;
+        //isAccept = true;
+    };
+    
+    /**
+     * increment currentStepNb
+     * @param _solution unused
+     */
+    virtual void updateParam(EOT & _solution) {
+        currentStepNb++;
+    };
+    
+    /**
+     * continue if there is a neighbor and it is remainds some steps to do
+     * @param _solution the solution
+     * @return true if there is still some steps to perform
+     */
+    virtual bool isContinue(EOT & _solution) {
+        return currentStepNb < maxSteps;
+    };
+    
+    /**
+     * alpha required by moMetropolisHastingsExplorer
+     * @param _solution the solution
+     * @return a real between 0 and 1 representing the probability of accepting a worse solution
+     */
+    double alpha(EOT & _solution) {
+        if (selectedNeighbor.fitness() == 0)
+            return selectedNeighbor.fitness() < (double) _solution.fitness() ? 1: 0;
+        return (double) _solution.fitness() / (double) selectedNeighbor.fitness();
+    }
+    
+private:
+    
+    // current number of steps
+    unsigned int currentStepNb;
+    
+    // maximum number of steps to perform
+    unsigned int maxSteps;
+    
+};
+
+
+#endif