RC

git-svn-id: svn://scm.gforge.inria.fr/svnroot/paradiseo@2710 331e1502-861f-0410-8da2-ba01fb791d7f

branches/rc2.0/eo/src/eoSigBinaryFlight.h

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+// -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
+
+//-----------------------------------------------------------------------------
+// eoSigBinaryFlight.h
+// (c) OPAC 2007, INRIA Futurs DOLPHIN
+/*
+    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: thomas.legrand@lifl.fr
+                 clive.canape@inria.fr
+ */
+//-----------------------------------------------------------------------------
+
+#ifndef EOSIGBINARYFLIGHT_H
+#define EOSIGBINARYFLIGHT_H
+
+//-----------------------------------------------------------------------------
+#include <eoBinaryFlight.h>
+//-----------------------------------------------------------------------------
+
+
+
+/**
+ *      Binary flight for particle swarm optimization based on the sigmoid function. Velocities are expected to be "double"
+ *  Consider Pi to be the i-th position of a particle and Vi to be the i-th velocity of the same particle :
+ *              if rand[0;1] < sig(Vi) (Vi <=> double)
+ *                      Pi=1
+ *          else
+ *                      Pi=0
+ *
+ *      @ingroup Variators
+ */
+template < class POT > class eoSigBinaryFlight:public eoBinaryFlight < POT >
+{
+
+public:
+
+    /**
+     * Constructor.
+     */
+    eoSigBinaryFlight (){slope = 1;}
+    eoSigBinaryFlight (unsigned _slope){slope = _slope;}
+
+
+    /**
+     * Sigmoid function
+     */
+    double sigmoid( double _value)
+    {
+        return(1/(1+ exp(- _value/slope)));
+
+    }
+
+    /**
+     * Apply the sigmoid binary flight to a particle.
+     *
+     */
+    void operator  () (POT & _po)
+    {
+
+        for (unsigned j = 0; j < _po.size (); j++)
+        {
+            double sigma=rng.uniform(1);
+
+            if (sigma < sigmoid(_po.velocities[j]))
+                _po[j]=1;
+            else
+                _po[j]=0;
+        }
+
+        // invalidate the fitness because the positions have changed
+        _po.invalidate();
+    }
+
+private :
+        unsigned slope;
+
+};
+
+
+
+#endif /*EOSIGBINARYFLIGHT_H */