Archive.cpp

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/*!
 * 
 *
 * \brief       Demonstration of the archive fitness function wrapper.
 * 
 * 
 *
 * \author      Tobias Glasmachers
 * \date        2013
 *
 *
 * \par Copyright 1995-2017 Shark Development Team
 * 
 * <BR><HR>
 * This file is part of Shark.
 * <http://shark-ml.org/>
 * 
 * Shark 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 3 of the License, or
 * (at your option) any later version.
 * 
 * Shark 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 Shark.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include <shark/Algorithms/DirectSearch/CMA.h>
#include <shark/ObjectiveFunctions/Benchmarks/Benchmarks.h>
#include <shark/ObjectiveFunctions/EvaluationArchive.h>


using namespace shark;
using namespace std;


int main() {
    cout.setf( ios_base::scientific );
    cout.precision( 10 );

    // Instantiate the problem
    Sphere sphere( 2 );
    sphere.setNumberOfVariables( 2 );

    // Create an archive object as a wrapper around the problem
    typedef EvaluationArchive< RealVector, double> ArchiveType;
    typedef EvaluationArchive< RealVector, double>::PointResultPairConstIterator ArchiveIteratorType;
    ArchiveType wrapper(&sphere);

    // Initialize the optimizer for the objective function instance.
    CMA cma;
    wrapper.init();
    cma.init( wrapper );

    // Iterate the optimizer until a solution of sufficient quality is found.
    const double target = 1e-4;
    cout << "Optimize the sphere benchmark problem to target accuracy " << target << endl;
    do {
        // Note the use of the wrapper instead of the fitness function:
        cma.step( wrapper );

        // Report information on the optimizer state and the current solution to the console.
        cout << sphere.evaluationCounter() << " "
            << cma.solution().value << " "
            << cma.solution().point << " "
            << cma.sigma() << endl;
    } while (cma.solution().value > target);

    // output archive contents (all visited search points)
    size_t N = wrapper.size();
    cout << endl;
    cout << "The archive contains " << N << " evaluated search points:" << endl;
    for (ArchiveIteratorType it=wrapper.begin(); it != wrapper.end(); ++it)
    {
        RealVector const& x = it->point;
        double fx = it->result;
        cout << "   f( " << x << " ) = " << fx << endl;
    }
}