A case study:Y-库存量,Ⅹ--销售额(lag=3) PDL expression: pdl series name, lags, order, options) The constraint options are 1 constrain the near end of the distribution to zero 2 constrain the far end of the distribution to zero 3 constrain both the near and far end of the distribution to zero By default, Eviews does not constrain the endpoints of the pdlA case study：Y---库存量，X---销售额（lag=3) PDL expression: pdl(series_name,lags,order,options) The constraint options are: ◼ 1 constrain the near end of the distribution to zero. ◼ 2 constrain the far end of the distribution to zero. ◼ 3 constrain both the near and far end of the distribution to zero. By default, EViews does not constrain the endpoints of the PDL