cs231n assignment1 two_layer_net 反向传播 详解

$$\begin{gathered} L=\frac{1}{N}{\sum }_{i=1}^N-log(\frac{e^{S_{y_i}}}{{\sum }_j{e}^{S_j}})+\lambda R(W1)+\lambda R(W2) \\ S=W_{2}max(0,W_{1}x+b1)+b2 \end{gathered}$$

$注意：\frac{dL}{dW}\ne \frac{dL}{d{S}_{y_i}}\ast \frac{d{S}_{y_i}}{dW}+\frac{dL}{d{S}_j}\ast \frac{d{S}_j}{dW}$，因为$S_{y_{}}$