说明：  BP神经网络算法，BP(back propagation)神经网络是一种按照误差逆向传播算法训练的多层前馈神经网络，是应用最广泛的神经网络。
(BP (back propagation) neural network is a kind of multilayer feedforward neural network which is trained according to the error back propagation algorithm. It is the most widely used neural network.)