docs: public CubicSplineCurve transpose()
      {
          List<Point> tr = new ArrayList<Point>();
          for (int ii=0;ii<S.length;ii++)
          {
              tr.add(new AbstractPoint(S[ii].getY(), S[ii].getX()));
          }
          if (tr.get(0).getX() > tr.get(tr.size()-1).getX())    // reverse order
          {
              Collections.reverse(tr);
          }
          return new CubicSplineCurve(tr);
      }