LLD法、ROR法、差分法三种对时间序列消去趋势的方法。LLD法作用最强，其次是ROR法，最后是差分法。用于股票和期货序列。能用于任何用Excel写的时间序列。-LLD law, ROR method, differential method three time-series trends elimination. LLD law the strongest effect, followed by the ROR method, final difference method. Used to