public double norm_vector(double[] z) {
    double sum = 0;

    for (int i = 0; i < problem.getNumberOfObjectives(); i++) {
      sum += z[i] * z[i];
    }

    return Math.sqrt(sum);
  }
public double norm_vector ( double [ ] z ) { double sum = 0 ; for ( int i = 0 ; i < problem . getNumberOfObjectives ( ) ; i ++ ) { sum += z [ i ] * z [ i ] ; } return Math . sqrt ( sum ) ; }
Calculate the norm of the vector