float operator() (Harmony const& h) const {
float result = 0.0;
for (unsigned i = 0; i < h.size(); ++i)
result += h.at(i);
return result;
}
float operator() (Harmony const& h) const {
float x = h.at(0);
float y = h.at(1);
float result = (1-x)*(1-x) + 100*(y-x*x)*(y-x*x);
return result;
}