说明：  本人用matlab编写的rels(最小二乘法），rls(递推增广最小二乘法),riv(辅助变量法递推算法)的程序，都是2阶的，稍改动就可以变成其它阶次
(I use matlab prepared rels (least squares), rls (augmented recursive least squares method), riv (auxiliary variable method recursive algorithm) procedure, are 2 bands, a little change can be turned into other order)