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eodev/eo/src/es/eoSBXcross.h
2004-06-23 23:19:17 +00:00

133 lines
3.9 KiB
C++

// -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
//-----------------------------------------------------------------------------
// eoSBXcross.h
// (c) Maarten Keijzer 2000 - Marc Schoenauer 2001
/*
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: Marc.Schoenauer@polytechnique.fr
mak@dhi.dk
*/
//-----------------------------------------------------------------------------
#include <algorithm> // swap_ranges
#include <utils/eoParser.h>
#include <utils/eoRNG.h>
#include <es/eoReal.h>
#include <utils/eoRealBounds.h>
#include <utils/eoRealVectorBounds.h>
template<class EOT> class eoSBXCrossover: public eoQuadOp<EOT>
{
public:
/****
* (Default) Constructor.
* The bounds are initialized with the global object that says: no bounds.
*
*
*/
eoSBXCrossover(const double& _eta = 1.0) :
bounds(eoDummyVectorNoBounds), eta(_eta), range(1) {}
//////////////////////////////////////////////
/**
* Constructor with bounds
* @param _bounds an eoRealVectorBounds that contains the bounds
* @param _alphaMin the amount of exploration OUTSIDE the parents
* as in BLX-alpha notation (Eshelman and Schaffer)
* 0 == contractive application
* Must be positive
*/
eoSBXCrossover(eoRealVectorBounds & _bounds,
const double& _eta = 1.0) :
bounds(_bounds), eta(_eta), range(1) {}
///////////////////////////////////////////////
//////////////////////////////////////////////
/**
* Constructor from a parser. Will read from the argument parser
* eoRealVectorBounds that contains the bounds
* eta, the SBX parameter
*/
eoSBXCrossover(eoParser & _parser) :
// First, decide whether the objective variables are bounded
// Warning, must be the same keywords than other possible objectBounds elsewhere
bounds (_parser.getORcreateParam(eoDummyVectorNoBounds, "objectBounds", "Bounds for variables", 'B', "Variation Operators").value()) ,
// then get eta value
eta (_parser.getORcreateParam(1.0, "eta", "SBX eta parameter", '\0', "Variation Operators").value()) ,
range(1) {}
/// The class name.
virtual std::string className() const { return "eoSBXCrossover"; }
/*****************************************
* SBX crossover - modifies both parents *
* @param _eo1 The first parent *
* @param _eo2 The first parent *
*****************************************/
bool operator()(EOT& _eo1, EOT& _eo2)
{
unsigned i;
double r1, r2, beta;
for (i=0; i<_eo1.size(); i++)
{
double u = rng.uniform(range) ;
if ( u <= 0.5 )
beta = exp( (1/(eta+1))*log(2*u));
else
beta = exp((1/(eta+1))*log(1/(2*(1-u))));
r1=_eo1[i];
r2=_eo2[i];
_eo1[i] =0.5*((1+beta)*r1+(1-beta)*r2);
_eo2[i] =0.5*((1-beta)*r1+(1+beta)*r2);
if(!(bounds.isInBounds(i,_eo1[i])))
bounds.foldsInBounds(i,_eo1[i]);
if(!(bounds.isInBounds(i,_eo2[i])))
bounds.foldsInBounds(i,_eo2[i]);
}
return true;
}
protected:
eoRealVectorBounds & bounds;
double eta;
double range; // == 1
};