Function update

examples/machine_learning/geneticalgorithm.cpp:19–22

static const float DefaultTopFittest = 0.5;

array update(const array& searchSpace, const array& sampleX,
             const array& sampleY, const int n) {
    return searchSpace(sampleY * n + sampleX);
}

array selectFittest(const array& sampleZ, const int nSamples,
                    const float topFit = DefaultTopFittest) {