GEPChromosomeMutGauss.cpp

#include "GEPChromosomeMutGauss.h"
 
namespace GEPChromosome{
    void GEPChromosomeMutGauss::registerParameters(StateP state)
    {
        myGenotype_->registerParameter(state, "mut.gauss", (voidP) new double(0), ECF::DOUBLE);
    }
 
    bool GEPChromosomeMutGauss::initialize(StateP state)
    {
        voidP sptr = myGenotype_->getParameterValue(state, "mut.gauss");
        probability_ = *((double*)sptr.get());
        engine_.seed((uint)time(NULL));
        return true;
    }
 
    bool GEPChromosomeMutGauss::mutate(GenotypeP gene){
        GEPChromosome* chr = (GEPChromosome*)(gene.get());
        if (chr->dcLength > 0){
            // mutate a single random point in the Dc domain by adding Gaussian noise to it
            // Select a random gene
            uint iGene = state_->getRandomizer()->getRandomInteger(0, chr->genes - 1);
            uint geneOffset = iGene * chr->geneLength;
            uint constOffset = geneOffset + chr->headLength + chr->tailLength; // this is where the Dc of the selected gene begins
            // Select a random point in the Dc tail
            uint iPoint = constOffset + state_->getRandomizer()->getRandomInteger(0, (uint)(chr->dcLength) - 1);
 
            double oldValue;
            Tree::PrimitiveP oldPrim = chr->at(iPoint)->primitive_;
            chr->at(iPoint)->primitive_->getValue(&oldValue);
            std::string oldName = chr->at(iPoint)->primitive_->getName();
 
            // generate Gauss noise offset and add it
            boost::normal_distribution<double> N(0, 1);
            double offset = N.operator () < boost::lagged_fibonacci607 > (engine_);
            double newValue = oldValue + offset;
 
            // change double ERC value and name
            std::stringstream ss;
            ss << newValue;
            std::string newName;
            ss >> newName;
            newName = DBL_PREFIX + newName;
 
            oldPrim->setName(newName);
            oldPrim->setValue(&newValue);
            // print result
            std::stringstream log;
            log << "GEPMutGauss successful (oldNode = " << oldName << ", newNode = " << newName << ")";
            ECF_LOG(state_, 5, log.str());
        }
        return true;
    }
}