code: public double evalG(BinarySolution solution) {
      double res = 0.0;
      for (int i = 1; i < solution.getNumberOfVariables(); i++) {
        res += evalV(u(solution.getVariableValue(i)));
      }
  
      return res;
    }
docs: Returns the value of the ZDT5 function G.
  
  @param solution The solution.