Another perspective of matrix multiplication (row-based/column based)
Q: How to represent “substract 3$\times$ row 1 from row 2” in matrix form?
A:
[1,0,0] -> the first row of the output is a row combination of 1 first row, 0 second row and 0 third row
[-3,1,0] $\times$M ->-> the second row of the output is a row combination of -3 first row, 1 second row and 0 third row
[0,0,1]
实在是太美了。为什么之前没好好听课 就抱着高中奥赛的东西乐享其成呢。