第2211题:奇异值分解
矩阵 A=[1−1−222−2]\bold{A}=\begin{bmatrix} 1 & -1 \\ -2 & 2 \\ 2 & -2 \end{bmatrix}A=⎣⎡1−22−12−2⎦⎤ 的一个奇异值分解为:A=UΣVT\bold{A=U \Sigma V^T}A=UΣVT ,猜一下,其中 Σ\bold{\Sigma}Σ 可能为( ).
A. Σ=[12−121212]\bold{\Sigma}=\begin{bmatrix} \dfrac{1}{\sqrt{2}} & -\dfrac{1}{\sqrt{2}} \\ \dfrac{1}{\sqrt{2}} & \dfrac{1}{\sqrt{2}} \end{bmatrix}Σ=⎣⎢⎡√21√21−√21√21⎦⎥⎤
B. Σ=[12−121212−1212]\bold{\Sigma}=\begin{bmatrix} \dfrac{1}{\sqrt{2}} & -\dfrac{1}{\sqrt{2}} \\ \dfrac{1}{\sqrt{2}} & \dfrac{1}{\sqrt{2}} \\ -\dfrac{1}{\sqrt{2}} & \dfrac{1}{\sqrt{2}} \end{bmatrix}Σ=⎣⎢⎢⎢⎢⎢⎡√21√21−√21−√21√21√21⎦⎥⎥⎥⎥⎥⎤
C. Σ=[32000] \bold{\Sigma}=\begin{bmatrix} 3\sqrt{2} & 0 \\ 0 & 0 \end{bmatrix}Σ=[3√2000]
D. Σ=[3200000]\bold{\Sigma}=\begin{bmatrix} 3\sqrt{2} & 0 \\ 0 & 0 \\ 0 & 0 \end{bmatrix}Σ=⎣⎡3√200000⎦⎤