矩阵的四则运算
Four arithmetic of matrix
设置A=[1 2 3 4;5 6 7 8]
B=[1 1 2 2;2 2 1 1]
C=A B 表示对应相加
D=A-B 表示对应相减
E=A*B’ B’表示A乘以B的转置，且需要确保A行数同B列数相同
F=A.*B 表示对应项相乘
G=A/B 可以理解为G*B=A G*B*pinv(B)=A*pinv(B) G=A*pinv(B)即A*B的逆
Set A=[1 2 3 4;5 6 7 8]
B=[1 1 2 2;2 2 1 1]
C=A B means corresponding addition
D=A-B means corresponding subtraction
E=A*B’ B’ represents the transpose of A multiplied by B, and it is necessary to ensure that the number of rows in A is the same as the number of columns in B
F=A.*B means the corresponding items are multiplied
G=A/B can be understood as G*B=A G*B*pinv(B)=A*pinv(B) G=A*pinv(B) is the inverse of A*B
矩阵的下标 Matrix subscript
设置A=magic(5) Set A=magic(5)
B=A（2，3）表示选取第二行，第三列
B=A(2,3) means to select the second row and the third column
C=A（3，：）表示选取第三行的所有列
C=A(3,:) means to select all the columns in the third row
D=A（：，4）表示选取所有行的第四列
D=A (:, 4) means to select the fourth column of all rows
