1. Example `[[4,0],[3,-5]]` (Previous example) | 3. Example `[[1,1,1],[-1,-3,-3],[2,4,4]]` (Next example) |
2. Example `[[1,0,1,0],[0,1,0,1]]`
Find SVD - Singular Value Decomposition ... `[[1,0,1,0],[0,1,0,1]]`Solution:
`A' * A`| = | | `1×1+0×0` | `1×0+0×1` | `1×1+0×0` | `1×0+0×1` | | | `0×1+1×0` | `0×0+1×1` | `0×1+1×0` | `0×0+1×1` | | | `1×1+0×0` | `1×0+0×1` | `1×1+0×0` | `1×0+0×1` | | | `0×1+1×0` | `0×0+1×1` | `0×1+1×0` | `0×0+1×1` | |
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| = | | `1+0` | `0+0` | `1+0` | `0+0` | | | `0+0` | `0+1` | `0+0` | `0+1` | | | `1+0` | `0+0` | `1+0` | `0+0` | | | `0+0` | `0+1` | `0+0` | `0+1` | |
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| = | | `1` | `0` | `1` | `0` | | | `0` | `1` | `0` | `1` | | | `1` | `0` | `1` | `0` | | | `0` | `1` | `0` | `1` | |
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| `A' * A = ` | | `1` | `0` | `1` | `0` | | | `0` | `1` | `0` | `1` | | | `1` | `0` | `1` | `0` | | | `0` | `1` | `0` | `1` | |
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Find Eigen vector for `A' * A` `|A' * A-lamdaI|=0` | `(1-lamda)` | `0` | `1` | `0` | | | `0` | `(1-lamda)` | `0` | `1` | | | `1` | `0` | `(1-lamda)` | `0` | | | `0` | `1` | `0` | `(1-lamda)` | |
| = 0 |
`:.(1-lamda) × |[(1-lamda),0,1],[0,(1-lamda),0],[1,0,(1-lamda)]|+0 × |[0,0,1],[1,(1-lamda),0],[0,0,(1-lamda)]|+1 × |[0,(1-lamda),1],[1,0,0],[0,1,(1-lamda)]|+0 × |[0,(1-lamda),0],[1,0,(1-lamda)],[0,1,0]|=0` `:.(1-lamda) × (-2lamda+3lamda^2-lamda^3)+0 × (0)+1 × (2lamda-lamda^2)+0 × (0)=0` `:.(-2lamda+5lamda^2-4lamda^3+lamda^4)+(0)+(2lamda-lamda^2)+(0)=0` `:.(lamda^4-4lamda^3+4lamda^2)=0` `:.lamda^2(lamda-2)(lamda-2)=0` `:.lamda^2=0 or (lamda-2)=0 or (lamda-2)=0` `:.lamda=0 or lamda=2 or lamda=2` `:.` The eigenvalues of the matrix `A' * A` are given by `lamda=0,2` 1. Eigenvectors for `lamda=2`
1. Eigenvectors for `lamda=2` | = | | `-1` | `0` | `1` | `0` | | | `0` | `-1` | `0` | `1` | | | `1` | `0` | `-1` | `0` | | | `0` | `1` | `0` | `-1` | |
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Now, reduce this matrix `R_1 larr R_1-:(-1)` | = | | `1` | `0` | `-1` | `0` | | | `0` | `-1` | `0` | `1` | | | `1` | `0` | `-1` | `0` | | | `0` | `1` | `0` | `-1` | |
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`R_3 larr R_3- R_1` | = | | `1` | `0` | `-1` | `0` | | | `0` | `-1` | `0` | `1` | | | `0` | `0` | `0` | `0` | | | `0` | `1` | `0` | `-1` | |
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`R_2 larr R_2-:(-1)` | = | | `1` | `0` | `-1` | `0` | | | `0` | `1` | `0` | `-1` | | | `0` | `0` | `0` | `0` | | | `0` | `1` | `0` | `-1` | |
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`R_4 larr R_4- R_2` | = | | `1` | `0` | `-1` | `0` | | | `0` | `1` | `0` | `-1` | | | `0` | `0` | `0` | `0` | | | `0` | `0` | `0` | `0` | |
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The system associated with the eigenvalue `lamda=2` | `(A' * A-2I)` | | = | | `1` | `0` | `-1` | `0` | | | `0` | `1` | `0` | `-1` | | | `0` | `0` | `0` | `0` | | | `0` | `0` | `0` | `0` | |
| | | = | |
`=>x_1-x_3=0,x_2-x_4=0` `=>x_1=x_3,x_2=x_4` `:.` eigenvectors corresponding to the eigenvalue `lamda=2` is Let `x_3=1,x_4=0` Let `x_3=0,x_4=1` 1. Orthogonal Eigenvectors for `lamda=2` 3. Eigenvectors for `lamda=0`
3. Eigenvectors for `lamda=0` | = | | `1` | `0` | `1` | `0` | | | `0` | `1` | `0` | `1` | | | `1` | `0` | `1` | `0` | | | `0` | `1` | `0` | `1` | |
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Now, reduce this matrix `R_3 larr R_3- R_1` | = | | `1` | `0` | `1` | `0` | | | `0` | `1` | `0` | `1` | | | `0` | `0` | `0` | `0` | | | `0` | `1` | `0` | `1` | |
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`R_4 larr R_4- R_2` | = | | `1` | `0` | `1` | `0` | | | `0` | `1` | `0` | `1` | | | `0` | `0` | `0` | `0` | | | `0` | `0` | `0` | `0` | |
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The system associated with the eigenvalue `lamda=0` | `(A' * A-0I)` | | = | | `1` | `0` | `1` | `0` | | | `0` | `1` | `0` | `1` | | | `0` | `0` | `0` | `0` | | | `0` | `0` | `0` | `0` | |
| | | = | |
`=>x_1+x_3=0,x_2+x_4=0` `=>x_1=-x_3,x_2=-x_4` `:.` eigenvectors corresponding to the eigenvalue `lamda=0` is Let `x_3=1,x_4=0` Let `x_3=0,x_4=1` 3. Orthogonal Eigenvectors for `lamda=0` For Eigenvector-1 `(1,0,1,0)`, Length L = `sqrt(|1|^2+|0|^2+|1|^2+|0|^2)=1.4142` So, normalizing gives `v_1=((1)/(1.4142),(0)/(1.4142),(1)/(1.4142),(0)/(1.4142))=(0.7071,0,0.7071,0)`For Eigenvector-2 `(0,1,0,1)`, Length L = `sqrt(|0|^2+|1|^2+|0|^2+|1|^2)=1.4142` So, normalizing gives `v_2=((0)/(1.4142),(1)/(1.4142),(0)/(1.4142),(1)/(1.4142))=(0,0.7071,0,0.7071)`For Eigenvector-3 `(-1,0,1,0)`, Length L = `sqrt(|-1|^2+|0|^2+|1|^2+|0|^2)=1.4142` So, normalizing gives `v_3=((-1)/(1.4142),(0)/(1.4142),(1)/(1.4142),(0)/(1.4142))=(-0.7071,0,0.7071,0)`For Eigenvector-4 `(0,-1,0,1)`, Length L = `sqrt(|0|^2+|-1|^2+|0|^2+|1|^2)=1.4142` So, normalizing gives `v_4=((0)/(1.4142),(-1)/(1.4142),(0)/(1.4142),(1)/(1.4142))=(0,-0.7071,0,0.7071)`Solution `U` is found using formula `u_i=1/sigma_i A*v_i` | `:. Sigma = ` | | `sqrt(2)` | `0` | `0` | `0` | | | `0` | `sqrt(2)` | `0` | `0` | |
| `=` | | `1.4142` | `0` | `0` | `0` | | | `0` | `1.4142` | `0` | `0` | |
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| `:. V = ` | `[v_1,v_2,v_3,v_4]` | `=` | | `0.7071` | `0` | `-0.7071` | `0` | | | `0` | `0.7071` | `0` | `-0.7071` | | | `0.7071` | `0` | `0.7071` | `0` | | | `0` | `0.7071` | `0` | `0.7071` | |
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Verify Solution `A = U Sigma V^T`| `U×Sigma` | = | | × | | `1.41421` | `0` | `0` | `0` | | | `0` | `1.41421` | `0` | `0` | |
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| = | | `0.99999×1.41421+0×0` | `0.99999×0+0×1.41421` | `0.99999×0+0×0` | `0.99999×0+0×0` | | | `0×1.41421+0.99999×0` | `0×0+0.99999×1.41421` | `0×0+0.99999×0` | `0×0+0.99999×0` | |
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| = | | `1.4142+0` | `0+0` | `0+0` | `0+0` | | | `0+0` | `0+1.4142` | `0+0` | `0+0` | |
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| = | | `1.4142` | `0` | `0` | `0` | | | `0` | `1.4142` | `0` | `0` | |
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| `(U × Sigma)×(V^T)` | = | | `1.4142` | `0` | `0` | `0` | | | `0` | `1.4142` | `0` | `0` | |
| × | | `0.70711` | `0` | `0.70711` | `0` | | | `0` | `0.70711` | `0` | `0.70711` | | | `-0.70711` | `0` | `0.70711` | `0` | | | `0` | `-0.70711` | `0` | `0.70711` | |
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| = | | `1.4142×0.70711+0×0+0×(-0.70711)+0×0` | `1.4142×0+0×0.70711+0×0+0×(-0.70711)` | `1.4142×0.70711+0×0+0×0.70711+0×0` | `1.4142×0+0×0.70711+0×0+0×0.70711` | | | `0×0.70711+1.4142×0+0×(-0.70711)+0×0` | `0×0+1.4142×0.70711+0×0+0×(-0.70711)` | `0×0.70711+1.4142×0+0×0.70711+0×0` | `0×0+1.4142×0.70711+0×0+0×0.70711` | |
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| = | | `0.99999+0+0+0` | `0+0+0+0` | `0.99999+0+0+0` | `0+0+0+0` | | | `0+0+0+0` | `0+0.99999+0+0` | `0+0+0+0` | `0+0.99999+0+0` | |
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| = | | `0.99999` | `0` | `0.99999` | `0` | | | `0` | `0.99999` | `0` | `0.99999` | |
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Solution is possible. Solution is possible.
This material is intended as a summary. Use your textbook for detail explanation. Any bug, improvement, feedback then
1. Example `[[4,0],[3,-5]]` (Previous example) | 3. Example `[[1,1,1],[-1,-3,-3],[2,4,4]]` (Next example) |
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