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eodev/eo/src/eoSigBinaryFlight.h
2011-05-05 16:54:00 +02:00

94 lines
2.6 KiB
C++

// -*- 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 */