次元削減PCA,ICA

$ \begin{pmatrix}x_1 \\ x_2 \\ \vdots \\ x_m\end{pmatrix}=\begin{pmatrix}a_{11} & a_{12} & \cdots & a_{1n} \\a_{21} & a_{22} & \cdots & a_{2n} \\\vdots & \vdots & \ddots & \vdots \\a_{m1} & a_{m2} & \cdots & a_{mn}\end{pmatrix}\begin{pmatrix}s_1 \\ s_2 \\ \vdots \\ s_n\end{pmatrix}