矩阵乘法
矩阵乘法入门 矩阵a\(\times\)矩阵b
矩阵a为n\(\times\)m 矩阵b为m\(\times\)p
矩阵a\(\times\)b为n\(\times\)p \(c_{ij}=\sum_{k=1}^{m}a_{ik}\times b_{kj}\)
\[\begin{matrix}
1 & 2 \\
3 & 4 \\
5 & 6
\end{matrix} \tag{a}
\]
\[\begin{matrix}
1 & 2 & 3 \\
4 & 5 & 6 \\
\end{matrix} \tag{b}
\]
\[\begin{matrix}
1*1+1*4+2*1+2*4 & 1*2+2*2+1*5+2*5 & 1*3+1*6+2*3+2*6 \\
3*1+4*1+3*4+4*4 & 3*2+3*5+4*2+4*5 & 3*3+3*6+4*3+4*6 \\
5*1+5*4+6*1+6*4 & 5*2+5*5+6*2+6*5 & 5*3+5*6+6*3+6*6
\end{matrix}\tag{c}
\]
\[\begin{matrix}
15 & 21 & 27 \\
35 & 49 & 63 \\
55 & 77 & 99
\end{matrix}\tag{c}
\]
