#BP神经网络简单python实现
BP神经网络的算法推导详见前面的文章:BP神经网络算法推导
##样例示意图
假设输入层有3个神经元,隐藏层有4个神经元,输出层有1个神经元,如图所示:
##样例参数说明
如图所示,隐藏层的结果(输出)为 Y → = X → × V i j \overrightarrow{Y} = \overrightarrow{X} \times V_{ij} Y=X×Vij:
{ y 0 = x 0 V 00 + x 1 V 10 + x 2 V 20 y 1 = x 0 V 01 + x 1 V 11 + x 2 V 21 y 2 = x 0 V 02 + x 1 V 12 + x 2 V 22 y 3 = x 0 V 03 + x 1 V 13 + x 2 V 23 \left\{ \begin{aligned} y_{0}=x_{0}V_{00}+x_{1}V_{10}+x_{2}V_{20} \\ y_{1}=x_{0}V_{01}+x_{1}V_{11}+x_{2}V_{21} \\ y_{2}=x_{0}V_{02}+x_{1}V_{12}+x_{2}V_{22} \\ y_{3}=x_{0}V_{03}+x_{1}V_{13}+x_{2}V_{23} \end{aligned} \right. ⎩⎪⎪⎪⎪⎨⎪⎪⎪⎪⎧y0=x0V00+x1V10+x2V20y1=x0V01+x1V11+x2V21y