\eqarray{H=& [h(x_1)^T,\cdots,h(x_N)^T]^T \\ =& [\matrix{g(w_1 x_1+b_1) & \cdots & g(w_L x_1+b_L) \\ \vdots & \ddots & \vdots \\ g(w_1 x_N+b_1) & \cdots & g(w_L x_N+b_L)}]_{N \times L}}
&的引起的那条竖线可以通过backspace或者delete删除
[\matrix{a_i x & b \\ c & d}]
\eqarray{10&x+&3&y=2@3&x+&13&y=4}#(1)
[\matrix{g(w_1 x_1+b_1) & \cdots & g(w_L x_1+b_L) \\ \vdots & \ddots & \vdots \\ g(w_1 x_N+b_1) & \cdots & g(w_L x_N+b_L)}]
