From b151ca140d7032bff9cebfecac5145ad40de29f2 Mon Sep 17 00:00:00 2001
From: verel <verel@mariner.home>
Date: Mon, 10 Nov 2014 15:58:56 +0100
Subject: [PATCH] Add incremental evaluation of NK landscape when several bits
 could be modified

---
 .../eval/moNKlandscapesBitsIncrEval.h         | 146 ++++++++++++++++++
 1 file changed, 146 insertions(+)
 create mode 100644 mo/src/problems/eval/moNKlandscapesBitsIncrEval.h

diff --git a/mo/src/problems/eval/moNKlandscapesBitsIncrEval.h b/mo/src/problems/eval/moNKlandscapesBitsIncrEval.h
new file mode 100644
index 000000000..c9a0ff0f3
--- /dev/null
+++ b/mo/src/problems/eval/moNKlandscapesBitsIncrEval.h
@@ -0,0 +1,146 @@
+/*
+ <moNKlandscapesBitsIncrEval.h>
+ Copyright (C) DOLPHIN Project-Team, INRIA Lille - Nord Europe, 2006-2010
+ 
+ Sebastien Verel, Arnaud Liefooghe, Jeremie Humeau
+ 
+ This software is governed by the CeCILL license under French law and
+ abiding by the rules of distribution of free software.  You can  ue,
+ 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".
+ 
+ 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 _moNKlandscapesBitsIncrEval_H
+#define _moNKlandscapesBitsIncrEval_H
+
+#include <eval/moEval.h>
+#include <eval/nkLandscapesEval.h>
+#include <vector>
+
+/**
+ *
+ * Incremental evaluation function (1 bit flip, Hamming distance 1)
+ * for the NK-landscapes problem
+ *
+ *
+ */
+template< class Neighbor >
+class moNKlandscapesBitsIncrEval : public moEval<Neighbor>
+{
+public:
+    typedef typename Neighbor::EOT EOT;
+    
+    /*
+     * Constructor
+     *
+     * @param _nk fitness function of the NK landscapes
+     */
+    moNKlandscapesBitsIncrEval(nkLandscapesEval<EOT> & _nk) : nk(_nk) {
+        inverseLinks = new std::vector<unsigned>[ nk.N ];
+        
+        // compute the contributions which are modified by flipping one bit
+        for(unsigned int i = 0; i < nk.N; i++)
+            for(unsigned int j = 0; j < nk.K + 1; j++) {
+                inverseLinks[ nk.links[i][j] ].push_back(i);
+            }
+    }
+    
+    /*
+     * Destructor
+     *
+     */
+    ~moNKlandscapesBitsIncrEval() {
+        delete [] inverseLinks;
+    }
+    
+    /*
+     * incremental evaluation of the neighbor for the oneMax problem
+     * @param _solution the solution to move (bit string)
+     * @param _neighbor the neighbor to consider (of type moBitNeigbor)
+     */
+    virtual void operator()(EOT & _solution, Neighbor & _neighbor) {
+        unsigned int b;
+
+        unsigned sig, nonSig;
+        unsigned i;
+        
+        double delta = 0 ;
+        
+        for(unsigned k = 0; k < _neighbor.nBits; k++) {
+            b = _neighbor.bits[k];
+
+            for(unsigned int j = 0; j < inverseLinks[b].size(); j++) {
+                i = inverseLinks[b][j];
+                sigma(_solution, i, b, sig, nonSig);
+                delta += nk.tables[i][nonSig] - nk.tables[i][sig];
+            }
+            
+            // move the solution on this bit
+            _solution[b] = !_solution[b];
+        }
+
+        // move back the solution
+        for(unsigned k = 0; k < _neighbor.nBits; k++) {
+            b = _neighbor.bits[k];
+            _solution[b] = !_solution[b];
+        }
+        //std::cout << delta << std::endl;
+        
+        _neighbor.fitness(_solution.fitness() + delta / (double) nk.N);
+    }
+    
+private:
+    // Original nk fitness function
+    nkLandscapesEval<EOT> & nk;
+    
+    // give the list of contributions which are modified when the corresponding bit is flipped
+    std::vector<unsigned> * inverseLinks;
+    
+    /**
+     * Compute the mask of the linked bits, and the mask when the bit is flipped
+     *
+     * @param _solution the solution to evaluate
+     * @param i the bit of the contribution
+     * @param _bit the bit to flip
+     * @param sig value of the mask of contribution i
+     * @param nonSig value of the mask of contribution i when the bit _bit is flipped
+     */
+    void sigma(EOT & _solution, int i, unsigned _bit, unsigned & sig, unsigned & nonSig) {
+        sig    = 0;
+        nonSig = 0;
+        
+        unsigned int n = 1;
+        for(int j = 0; j < nk.K + 1; j++) {
+            if (_solution[ nk.links[i][j] ] == 1)
+                sig = sig | n;
+            
+            if (nk.links[i][j] == _bit)
+                nonSig = n;
+            
+            n = n << 1;
+        }
+        
+        nonSig = sig ^ nonSig;
+    }
+    
+};
+
+#endif
+