17. SVD - Singular Value Decomposition example
( Enter your problem )
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- Example `[[4,0],[3,-5]]`
- Example `[[1,0,1,0],[0,1,0,1]]`
- Example `[[1,1,1],[-1,-3,-3],[2,4,4]]`
- Example `[[2,3],[4,10]]`
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Other related methods
- Transforming matrix to Row Echelon Form
- Transforming matrix to Reduced Row Echelon Form
- Rank of matrix
- Characteristic polynomial of matrix
- Eigenvalues
- Eigenvectors (Eigenspace)
- Triangular Matrix
- LU decomposition using Gauss Elimination method of matrix
- LU decomposition using Doolittle's method of matrix
- LU decomposition using Crout's method of matrix
- Diagonal Matrix
- Cholesky Decomposition
- QR Decomposition (Gram Schmidt Method)
- QR Decomposition (Householder Method)
- LQ Decomposition
- Pivots
- Singular Value Decomposition (SVD)
- Moore-Penrose Pseudoinverse
- Power Method for dominant eigenvalue
- determinants using Sarrus Rule
- determinants using properties of determinants
- Row Space
- Column Space
- Null Space
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4. Example `[[2,3],[4,10]]`
Find SVD - Singular Value Decomposition ... `[[2,3],[4,10]]`
Solution:
Here we are trying to find out two solutions using `A*A'` and `A'*A`
`1^"st"` Solution using `A*A'` for normalized vectors `u_i`
`A * A'`= | | `2×2+3×3` | `2×4+3×10` | | | `4×2+10×3` | `4×4+10×10` | |
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= | | `4+9` | `8+30` | | | `8+30` | `16+100` | |
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Find Eigen vector for `A * A'`
`|A * A'-lamdaI|=0`
| `(13-lamda)` | `38` | | | `38` | `(116-lamda)` | |
| = 0 |
`:.(13-lamda) × (116-lamda) - 38 × 38=0`
`:.(1508-129lamda+lamda^2)-1444=0`
`:.(lamda^2-129lamda+64)=0`
`:.(lamda-0.4980469)(lamda-128.5019531)=0`
`:.(lamda-0.4980469)=0 or(lamda-128.5019531)=0 `
`:.` The eigenvalues of the matrix `A * A'` are given by `lamda=0.4980469,128.5019531`,
1. Eigenvectors for `lamda=128.5019531`
1. Eigenvectors for `lamda=128.5019531` `A * A'-lamdaI = ` | | - `128.5019531` | |
= | | `-115.5019531` | `38` | | | `38` | `-12.5019531` | |
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Now, reduce this matrix `R_1 larr R_1-:-115.5019531` = | | `1` | `-0.32899877` | | | `38` | `-12.5019531` | |
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`R_2 larr R_2-38xx R_1` The system associated with the eigenvalue `lamda=128.5019531` `(A * A'-128.5019531I)` | | = | | | | = | |
`=>x_1-0.32899877x_2=0` `=>x_1=0.32899877x_2` `:.` eigenvectors corresponding to the eigenvalue `lamda=128.5019531` is Let `x_2=1`
2. Eigenvectors for `lamda=0.4980469`
2. Eigenvectors for `lamda=0.4980469` `A * A'-lamdaI = ` | | - `0.4980469` | |
= | | `12.5019531` | `38` | | | `38` | `115.5019531` | |
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Now, reduce this matrix interchanging rows `R_1 harr R_2` = | | `38` | `115.5019531` | | | `12.5019531` | `38` | |
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`R_1 larr R_1-:38` = | | `1` | `3.03952508` | | | `12.5019531` | `38` | |
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`R_2 larr R_2-12.5019531xx R_1` The system associated with the eigenvalue `lamda=0.4980469` `(A * A'-0.4980469I)` | | = | | | | = | |
`=>x_1+3.03952508x_2=0` `=>x_1=-3.03952508x_2` `:.` eigenvectors corresponding to the eigenvalue `lamda=0.4980469` is Let `x_2=1`
For Eigenvector-1 `(0.32899877,1)`, Length L = `sqrt(0.32899877^2+1^2)=1.05272987`
So, normalizing gives `u_1=(0.32899877/1.05272987,1/1.05272987)=(0.31251964,0.9499113)`
For Eigenvector-2 `(-3.03952508,1)`, Length L = `sqrt((-3.03952508)^2+1^2)=3.19979886`
So, normalizing gives `u_2=((-3.03952508)/3.19979886,1/3.19979886)=(-0.9499113,0.31251964)`
`2^"nd"` Solution using `A'*A` for normalized vectors `v_i`
`A' * A`= | | `2×2+4×4` | `2×3+4×10` | | | `3×2+10×4` | `3×3+10×10` | |
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= | | `4+16` | `6+40` | | | `6+40` | `9+100` | |
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Find Eigen vector for `A' * A`
`|A' * A-lamdaI|=0`
| `(20-lamda)` | `46` | | | `46` | `(109-lamda)` | |
| = 0 |
`:.(20-lamda) × (109-lamda) - 46 × 46=0`
`:.(2180-129lamda+lamda^2)-2116=0`
`:.(lamda^2-129lamda+64)=0`
`:.(lamda-0.4980469)(lamda-128.5019531)=0`
`:.(lamda-0.4980469)=0 or(lamda-128.5019531)=0 `
`:.` The eigenvalues of the matrix `A' * A` are given by `lamda=0.4980469,128.5019531`,
1. Eigenvectors for `lamda=128.5019531`
1. Eigenvectors for `lamda=128.5019531` `A' * A-lamdaI = ` | | - `128.5019531` | |
= | | `-108.5019531` | `46` | | | `46` | `-19.5019531` | |
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Now, reduce this matrix `R_1 larr R_1-:-108.5019531` = | | `1` | `-0.4239555` | | | `46` | `-19.5019531` | |
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`R_2 larr R_2-46xx R_1` The system associated with the eigenvalue `lamda=128.5019531` `(A' * A-128.5019531I)` | | = | | | | = | |
`=>x_1-0.4239555x_2=0` `=>x_1=0.4239555x_2` `:.` eigenvectors corresponding to the eigenvalue `lamda=128.5019531` is Let `x_2=1`
2. Eigenvectors for `lamda=0.4980469`
2. Eigenvectors for `lamda=0.4980469` `A' * A-lamdaI = ` | | - `0.4980469` | |
= | | `19.5019531` | `46` | | | `46` | `108.5019531` | |
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Now, reduce this matrix interchanging rows `R_1 harr R_2` = | | `46` | `108.5019531` | | | `19.5019531` | `46` | |
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`R_1 larr R_1-:46` = | | `1` | `2.35873811` | | | `19.5019531` | `46` | |
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`R_2 larr R_2-19.5019531xx R_1` The system associated with the eigenvalue `lamda=0.4980469` `(A' * A-0.4980469I)` | | = | | | | = | |
`=>x_1+2.35873811x_2=0` `=>x_1=-2.35873811x_2` `:.` eigenvectors corresponding to the eigenvalue `lamda=0.4980469` is Let `x_2=1`
For Eigenvector-1 `(0.4239555,1)`, Length L = `sqrt(0.4239555^2+1^2)=1.08615757`
So, normalizing gives `v_1=(0.4239555/1.08615757,1/1.08615757)=(0.39032597,0.92067673)`
For Eigenvector-2 `(-2.35873811,1)`, Length L = `sqrt((-2.35873811)^2+1^2)=2.56196126`
So, normalizing gives `v_2=((-2.35873811)/2.56196126,1/2.56196126)=(-0.92067673,0.39032597)`
`1^"st"` SVD Solution using `A*A'`
`:. Sigma = ` | | `sqrt(128.5019531)` | `0` | | | `0` | `sqrt(0.4980469)` | |
| `=` | | `11.3358702` | `0` | | | `0` | `0.70572438` | |
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`:. U = ` | `[u_1,u_2]` | `=` | | `0.31251964` | `-0.9499113` | | | `0.9499113` | `0.31251964` | |
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`V` is found using formula `v_i=1/sigma_i A^T*u_i`
`:. V = ` | | `0.39032597` | `-0.92067676` | | | `0.92067673` | `0.39032589` | |
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`2^"nd"` SVD Solution using `A'*A`
`:. Sigma = ` | | `sqrt(128.5019531)` | `0` | | | `0` | `sqrt(0.4980469)` | |
| `=` | | `11.3358702` | `0` | | | `0` | `0.70572438` | |
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`:. V = ` | `[v_1,v_2]` | `=` | | `0.39032597` | `-0.92067673` | | | `0.92067673` | `0.39032597` | |
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`U` is found using formula `u_i=1/sigma_i A*v_i`
`:. U = ` | | `0.31251965` | `-0.94991128` | | | `0.9499113` | `0.31251971` | |
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Verify `1^"st"` Solution `A = U Sigma V^T``U×Sigma` | = | | `0.312519644` | `-0.949911297` | | | `0.949911297` | `0.312519644` | |
| × | | `11.335870196` | `0` | | | `0` | `0.705724383` | |
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= | | `0.312519644×11.335870196-0.949911297×0` | `0.312519644×0-0.949911297×0.705724383` | | | `0.949911297×11.335870196+0.312519644×0` | `0.949911297×0+0.312519644×0.705724383` | |
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= | | `3.542682118+0` | `0-0.670375564` | | | `10.768071161+0` | `0+0.220552733` | |
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= | | `3.542682118` | `-0.670375564` | | | `10.768071161` | `0.220552733` | |
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`(U × Sigma)×(V^T)` | = | | `3.542682118` | `-0.670375564` | | | `10.768071161` | `0.220552733` | |
| × | | `0.390325966` | `0.920676731` | | | `-0.920676762` | `0.390325893` | |
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= | | `3.542682118×0.390325966-0.670375564×-0.920676762` | `3.542682118×0.920676731-0.670375564×0.390325893` | | | `10.768071161×0.390325966+0.220552733×-0.920676762` | `10.768071161×0.920676731+0.220552733×0.390325893` | |
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= | | `1.38280082+0.617199204` | `3.261664991-0.261664941` | | | `4.203057778-0.203057776` | `9.913912555+0.086087442` | |
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= | | `2.000000024` | `3.000000051` | | | `4.000000002` | `9.999999998` | |
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`1^"st"` Solution is possible. `1^"st"` Solution is possible.
Verify `2^"nd"` Solution `A = U Sigma V^T``U×Sigma` | = | | `0.312519645` | `-0.949911277` | | | `0.949911299` | `0.312519711` | |
| × | | `11.335870196` | `0` | | | `0` | `0.705724383` | |
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= | | `0.312519645×11.335870196-0.949911277×0` | `0.312519645×0-0.949911277×0.705724383` | | | `0.949911299×11.335870196+0.312519711×0` | `0.949911299×0+0.312519711×0.705724383` | |
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= | | `3.542682129+0` | `0-0.67037555` | | | `10.768071183+0` | `0+0.22055278` | |
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= | | `3.542682129` | `-0.67037555` | | | `10.768071183` | `0.22055278` | |
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`(U × Sigma)×(V^T)` | = | | `3.542682129` | `-0.67037555` | | | `10.768071183` | `0.22055278` | |
| × | | `0.390325965` | `0.92067673` | | | `-0.92067673` | `0.390325965` | |
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= | | `3.542682129×0.390325965-0.67037555×-0.92067673` | `3.542682129×0.92067673-0.67037555×0.390325965` | | | `10.768071183×0.390325965+0.22055278×-0.92067673` | `10.768071183×0.92067673+0.22055278×0.390325965` | |
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= | | `1.382800821+0.617199169` | `3.261664998-0.261664983` | | | `4.203057776-0.203057812` | `9.913912565+0.086087477` | |
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= | | `1.99999999` | `3.000000015` | | | `3.999999963` | `10.000000042` | |
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`2^"nd"` Solution is possible. `2^"nd"` Solution is possible.
This material is intended as a summary. Use your textbook for detail explanation. Any bug, improvement, feedback then
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