docs: public static double[][] convertFrontToArray(Front front) {
      if (front == null) {
        throw new NullFrontException();
      }
  
      double[][] arrayFront = new double[front.getNumberOfPoints()][] ;
  
      for (int i = 0; i < front.getNumberOfPoints(); i++) {
        arrayFront[i] = new double[front.getPoint(i).getDimension()] ;
        for (int j = 0 ; j < front.getPoint(i).getDimension(); j++) {
          arrayFront[i][j] = front.getPoint(i).getValue(j) ;
        }
      }
  
      return arrayFront ;
    }