D:/Projekt/ECF_trunk/ECF/tree/TreeMutGauss.cpp

#include "../ECF_base.h"
#include "Tree.h"
#include "TreeMutGauss.h"
#include <stdio.h>
#include <time.h>

#include "boost/random/normal_distribution.hpp"


namespace Tree
{

void TreeMutGauss::registerParameters(StateP state)
{
    myGenotype_->registerParameter(state, "mut.gauss", (voidP) new double(0), ECF::DOUBLE);
}


bool TreeMutGauss::initialize(StateP state)
{
    voidP sptr = myGenotype_->getParameterValue(state, "mut.gauss");
    probability_ = *((double*)sptr.get());

    engine_.seed((uint) time(NULL));
    return true;
}


bool TreeMutGauss::mutate(GenotypeP gene)
{
    Tree* tree = (Tree*) (gene.get());
    
    // try to select ERC node of type double
    uint iNode;
    uint tries = 0;
    std::string name;
    do {
        iNode = state_->getRandomizer()->getRandomInteger((int) tree->size());
        tries++;
    } while((name = tree->at(iNode)->primitive_->getName()).substr(0, 2) != DBL_PREFIX && tries < 4);

    if(name.substr(0, 2) != DBL_PREFIX) {
        ECF_LOG(state_, 5, "TreeMutGauss not successful.");
        return false;
    }

    double oldValue;
    PrimitiveP oldPrim = tree->at(iNode)->primitive_;
    tree->at(iNode)->primitive_->getValue(&oldValue);
    std::string oldName = tree->at(iNode)->primitive_->getName();

    // generate Gauss noise offset and add it
    // TODO: parametrize distribution!
    boost::normal_distribution<double> N(0, 1);

    // e.g. http://www.codepedia.com/1/CppBoostRandom
    // TODO: preserve state
    //boost::lagged_fibonacci607 engine(state_->getRandomizer()->getRandomInteger(100000) + 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);

    // new ERCs aren't stored in the PrimitiveSet

    std::stringstream log;
    log << "TreeMutGauss successful (oldNode = " << oldName << ", newNode = " << newName << ")";
    ECF_LOG(state_, 5, log.str());

    return true;
}

}