CRNFuzzyLogic.cpp

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/* Copyright 2008-2016 INSA-Lyon, ENS-Lyon
 * 
 * This file is part of libcrn.
 * 
 * libcrn 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.
 * 
 * libcrn 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 libcrn.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * file: FuzzyLogic.cpp
 * \author Jean DUONG, Yann LEYDIER
 */

#include <CRNMath/CRNFuzzyLogic.h>
#include <CRNMath/CRNRealToRealFunction.h>

using namespace crn;

RealToRealFunction FuzzyLogic::MakeCompatibility(const RealToRealFunction& f, const RealToRealFunction& g, size_t nbBins)
{
    RealToRealFunction c;
    c.SetImageSize(nbBins);

    double delta = 1.0 / double(nbBins - 1);
    double x = 0.0;

    for (size_t k = 0; k < nbBins; k++)
    {
        double sup = 0.0;
        try
        {
            MatrixDouble preF = f.MakePreimage(x);
            for (size_t i = 0; i < preF.GetCols(); i++)
            {
                double y = g.Evaluate(preF.At(0, i));

                if (y > sup)
                {
                    sup = y;
                }
            }   
        }
        catch (ExceptionNotFound&) { }
        c.SetElement(k, sup);
        x += delta;
    }

    c.SetLeftEndpoint(0.0);
    c.SetRightEndpoint(1.0);

    return c;
}

double FuzzyLogic::DefuzzificationCOG(double min, double max, const RealToRealFunction& f)
{
    double denominator = f.TrapezoidIntegral();

    if (denominator != 0.0)
    {
        URealToRealFunction newF = CloneAs<RealToRealFunction>(f);

        size_t n = newF->GetImageSize();
        double x = 0.0;
        double delta = 1.0 / double(n - 1);

        for (size_t k = 0; k < n; k++)
        {
            newF->SetElement(k, newF->At(k) * x);
            x += delta;
        }

        return newF->TrapezoidIntegral() / denominator;
    }
    else
    {
        return 0.0;
    }
}