docs: protected double evalG(DoubleSolution solution) {
      double g = 0.0;
      for (int var = 1; var < solution.getNumberOfVariables(); var++) {
        g += solution.getVariableValue(var);
      }
      g = g / (solution.getNumberOfVariables() - 1);
      g = Math.pow(g, 0.25);
      g = 9.0 * g;
      g = 1.0 + g;
      return g;
    }