paradiseo/edo/src/edoSamplerNormalAdaptive.h
2012-07-18 13:41:43 +02:00

87 lines
2.7 KiB
C++

/*
The Evolving Distribution Objects framework (EDO) is a template-based,
ANSI-C++ evolutionary computation library which helps you to write your
own estimation of distribution algorithms.
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 2.1 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
Copyright (C) 2010 Thales group
*/
/*
Authors:
Johann Dréo <johann.dreo@thalesgroup.com>
Pierre Savéant <pierre.saveant@thalesgroup.com>
*/
#ifndef _edoSamplerNormalAdaptive_h
#define _edoSamplerNormalAdaptive_h
#include <cmath>
#include <limits>
#include <edoSampler.h>
/** Sample points in a multi-normal law defined by a mean vector, a covariance matrix, a sigma scale factor and
* evolution paths. This is a step of the CMA-ES algorithm.
*/
#ifdef WITH_EIGEN
template< class EOT, typename EOD = edoNormalAdaptive< EOT > >
class edoSamplerNormalAdaptive : public edoSampler< EOD >
{
public:
typedef typename EOT::AtomType AtomType;
typedef typename EOD::Vector Vector;
typedef typename EOD::Matrix Matrix;
edoSamplerNormalAdaptive( edoRepairer<EOT> & repairer )
: edoSampler< EOD >( repairer)
{}
EOT sample( EOD& distrib )
{
unsigned int N = distrib.size();
assert( N > 0);
// T = vector of size elements drawn in N(0,1)
Vector T( N );
for ( unsigned int i = 0; i < N; ++i ) {
T( i ) = rng.normal();
}
assert(T.innerSize() == N );
assert(T.outerSize() == 1);
// mean(N,1) + sigma * B(N,N) * ( D(N,1) .* T(N,1) )
Vector sol = distrib.mean()
+ distrib.sigma()
* distrib.coord_sys() * (distrib.scaling().cwiseProduct(T) ); // C * T = B * (D .* T)
assert( sol.size() == N );
/*Vector sol = distrib.mean() + distrib.sigma()
* distrib.coord_sys().dot( distrib.scaling().dot( T ) );*/
// copy in the EOT structure (more probably a vector)
EOT solution( N );
for( unsigned int i = 0; i < N; i++ ) {
solution[i]= sol(i);
}
return solution;
}
};
#endif // WITH_EIGEN
#endif // !_edoSamplerNormalAdaptive_h