说明：  应用粒子群算法来寻找BP神经网络最优的初始权值还有阈值，本程序主要是以此来拟合函数，读者可以根据需要，小小地修改一下BP神经网络的代码，可以实现诸如模式识别等功能，收敛效果很好，
(Application of particle swarm algorithm to find the optimal initial BP neural network weights as well as the threshold value, the procedure is a way to fit function, readers can according to need, a little bit modified BP neural network code, can achieve such mode recognition and other functions, the convergence effect is very good,)