求(逐日、逐月、逐季、年际）异常序列x(n)和y(n)之间的滞后超前的相关系数rt(-nt:nt)，其中nt最大的滞后或超前时间（单位：日、月、季、年等）。-Lag ahead of the correlation coefficient between the demand (daily, monthly, quarterly basis, inter-annual) abnormal sequence x (n) and y (n) rt (-nt: nt), nt maximum lag or lead time (in : day, month, quarter, year, etc.).