更新说明：

此版本在版本1、2的基础上做了2点重大改进

1、改进了PhaSpa2VoltCoef函数算法，使得现算法的运行速度约是原算法的4倍

2、改进了volterra_train_lu函数算法，使得相对均方误差提高了约1000倍，新算法不再需要对样本做归一化处理-Update : This version of the 1,2 version on the basis of a 2:00 a significant improvement, improved PhaSpa2VoltCoef function algorithm, the algorithm makes is about speed of the original algorithm four times two, improved volterra_train_lu function algorithm, making relative mean square error raise about 1,000 times that the new algorithm is no longer required to do under a sample processing