说明：  bp算法的源代码，由于很多程序都是利用matlab工具箱函数做的，不利于是用这个性化设计，对于观察网络内部的结构也带来一定困难，这个算法就可以让社记者跟踪训练过程
(bp algorithm source code, a lot of procedures are using Matlab Toolbox function done, then use the negative nature of the design, the internal network for observation of the structure is also a certain difficulties, this algorithm can let reporters tracking the training process)