Professional Interests: numerical linear algebra, graph algorithms

Answered

Find border edges of the graph

The graph class doesn't have any functions based on coordinates of the points - it just knows about their connections. Use conve...

Find border edges of the graph

The graph class doesn't have any functions based on coordinates of the points - it just knows about their connections. Use conve...

16 jours ago | 1

| accepted

Answered

QR decomposition with the output of a permutation vector

The purpose of arranging all diagonal elements in descending order is to allow splitting R into two parts if A is low-rank or cl...

QR decomposition with the output of a permutation vector

The purpose of arranging all diagonal elements in descending order is to allow splitting R into two parts if A is low-rank or cl...

17 jours ago | 0

| accepted

Answered

How to add highlighted nodes and edges of a graph to the legend?

The problem here is that legend will only provide labels for what graphics recognizes as individual objects. So in a line plot,...

How to add highlighted nodes and edges of a graph to the legend?

The problem here is that legend will only provide labels for what graphics recognizes as individual objects. So in a line plot,...

23 jours ago | 1

| accepted

Answered

How to restore tensor after applied the PARAFAC model?

The three component vectors represent the 3 different dimensions here. For the one-component case (all are vectors), you can use...

How to restore tensor after applied the PARAFAC model?

The three component vectors represent the 3 different dimensions here. For the one-component case (all are vectors), you can use...

environ un mois ago | 0

| accepted

Answered

Create a graph from removed edges

The graph constructor has a syntax that specifies the number of nodes of the graph: graph(s, t, [], numnodes) if you pass the ...

Create a graph from removed edges

The graph constructor has a syntax that specifies the number of nodes of the graph: graph(s, t, [], numnodes) if you pass the ...

environ un mois ago | 0

| accepted

Answered

SVD computation using eig function

Try the formula the other way around, using U_tilde, V_tilde and A to compute D: >> U_tilde'*A*V_tilde ans = 70.0118 -0....

SVD computation using eig function

Try the formula the other way around, using U_tilde, V_tilde and A to compute D: >> U_tilde'*A*V_tilde ans = 70.0118 -0....

environ un mois ago | 0

| accepted

Answered

Using Singular value decomposition for feature extraction from images

Image compression using SVD is a pretty common example (although not the most efficient way to compress an image), here are some...

Using Singular value decomposition for feature extraction from images

Image compression using SVD is a pretty common example (although not the most efficient way to compress an image), here are some...

environ un mois ago | 0

Answered

Error using eig Input matrix contains NaN or Inf.

The function sossolve is part of a third-party tool, this seems to be their website: http://www.cds.caltech.edu/sostools/. It's ...

Error using eig Input matrix contains NaN or Inf.

The function sossolve is part of a third-party tool, this seems to be their website: http://www.cds.caltech.edu/sostools/. It's ...

environ un mois ago | 0

Answered

How to keep track of order eigenvalue in eig or eigs?

The eigenvalues returned by EIG are not sorted in any particular order generally (for some special types of matrices (e.g. exact...

How to keep track of order eigenvalue in eig or eigs?

The eigenvalues returned by EIG are not sorted in any particular order generally (for some special types of matrices (e.g. exact...

environ 2 mois ago | 1

Answered

Eigenvectors and the null function

I'm getting those two eigenvectors when I copy your code into MATLAB: >> D = [2 -1; -1 3]; eigs = eig(D); q1 = nu...

Eigenvectors and the null function

I'm getting those two eigenvectors when I copy your code into MATLAB: >> D = [2 -1; -1 3]; eigs = eig(D); q1 = nu...

environ 2 mois ago | 0

Answered

Block-diagonalization of a matrix

There is no direct function to do this. The best is probably to write a function that does a loop through the different blocks a...

Block-diagonalization of a matrix

There is no direct function to do this. The best is probably to write a function that does a loop through the different blocks a...

environ 2 mois ago | 0

Answered

How created a graph from unordered node list?

When a graph or digraph is specified using numbers, the assumption is that all nodes of this graph have numbers from 1:numberOfN...

How created a graph from unordered node list?

When a graph or digraph is specified using numbers, the assumption is that all nodes of this graph have numbers from 1:numberOfN...

environ 2 mois ago | 0

| accepted

Answered

nonsingular matrix (X) in GSVD function

These are just different but equivalent definitions: Both will result in the same C and S, the only difference is in how X is re...

nonsingular matrix (X) in GSVD function

These are just different but equivalent definitions: Both will result in the same C and S, the only difference is in how X is re...

environ 2 mois ago | 1

Answered

accuracy of two methods to solve eignvalues/eignvector problem

The second way is typically more accurate, because it doesn't incur additional round-off error when conputing inv(Sw) and when m...

accuracy of two methods to solve eignvalues/eignvector problem

The second way is typically more accurate, because it doesn't incur additional round-off error when conputing inv(Sw) and when m...

environ 2 mois ago | 0

| accepted

Answered

Sort eigenvectors matrix.

Take a look at rsf2csf. For a block-diagonal matrix with 1-by-1 and 2-by-2 blocks, it computes a diagonal eigenvalue matrix and ...

Sort eigenvectors matrix.

Take a look at rsf2csf. For a block-diagonal matrix with 1-by-1 and 2-by-2 blocks, it computes a diagonal eigenvalue matrix and ...

2 mois ago | 1

Answered

Eigenvectors of an SPD matrix being saved as complex doubles

EIG does not recognize the input matrix as symmetric because it's not exactly symmetric. If you compute A = Y'*Mh*Y norm(A - A...

Eigenvectors of an SPD matrix being saved as complex doubles

EIG does not recognize the input matrix as symmetric because it's not exactly symmetric. If you compute A = Y'*Mh*Y norm(A - A...

2 mois ago | 0

| accepted

Answered

Given a matrix A^n. Comparing normal multiplication versus Diagonalization. I expect the former to be faster but its not in my case

A^2 is just one matrix multiplication, A*A, which is much faster to do directly than the call to EIG. For larger n, A^n isn't ...

Given a matrix A^n. Comparing normal multiplication versus Diagonalization. I expect the former to be faster but its not in my case

A^2 is just one matrix multiplication, A*A, which is much faster to do directly than the call to EIG. For larger n, A^n isn't ...

3 mois ago | 0

| accepted

Answered

how to random initialize svd function in matlab??

The linear algebra functions in MATLAB are run-to-run reproducible, meaning if you call them twice with the exact same input, yo...

how to random initialize svd function in matlab??

The linear algebra functions in MATLAB are run-to-run reproducible, meaning if you call them twice with the exact same input, yo...

3 mois ago | 1

| accepted

Answered

EigenValues of a Vibrating system

Usually for finite element problems, the stiffness matrix is passed in as the first input, and the mass matrix as the second inp...

EigenValues of a Vibrating system

Usually for finite element problems, the stiffness matrix is passed in as the first input, and the mass matrix as the second inp...

3 mois ago | 0

| accepted

Answered

issues with Cholesky decomposition

This can happen if your matrix is close to symmetric positive semi-definite (meaning the smallest eigenvalue is around machine e...

issues with Cholesky decomposition

This can happen if your matrix is close to symmetric positive semi-definite (meaning the smallest eigenvalue is around machine e...

3 mois ago | 0

Answered

Can I preserve adding order when calling graph/addedge?

The edges in a graph are always presented in the same order (sort first by source node, secondarily be target node). You can mai...

Can I preserve adding order when calling graph/addedge?

The edges in a graph are always presented in the same order (sort first by source node, secondarily be target node). You can mai...

3 mois ago | 1

| accepted

Answered

Display only one eigenvalue of symbolic matrix

The eigs function is not supported for symbolic values, as it is specifically based on getting a good approximation based on an ...

Display only one eigenvalue of symbolic matrix

The eigs function is not supported for symbolic values, as it is specifically based on getting a good approximation based on an ...

3 mois ago | 0

Answered

how to do forward neighbor discovery in un-directed graph?

If I understand correctly, you want to find all nodes that are direct neighbors of n1, then all nodes that connect to n1 through...

how to do forward neighbor discovery in un-directed graph?

If I understand correctly, you want to find all nodes that are direct neighbors of n1, then all nodes that connect to n1 through...

3 mois ago | 0

Answered

Using eigs with singular matrix

The 'smallestabs' option in eigs depends on solving several linear systems with the matrix A that's being passed in. If A is sin...

Using eigs with singular matrix

The 'smallestabs' option in eigs depends on solving several linear systems with the matrix A that's being passed in. If A is sin...

4 mois ago | 0

| accepted

Answered

Change the alignment and font size of edgelabels

The edge labels provided with the plot of a graph can't be modified in terms of their alignment. However, you can add standard t...

Change the alignment and font size of edgelabels

The edge labels provided with the plot of a graph can't be modified in terms of their alignment. However, you can add standard t...

4 mois ago | 0

| accepted

Answered

a question for defining Custom Deep Learning Layer

You can use the svd in a custom layer, however, if the SVD is used in the forward method of a custom layer, this will likely req...

a question for defining Custom Deep Learning Layer

You can use the svd in a custom layer, however, if the SVD is used in the forward method of a custom layer, this will likely req...

4 mois ago | 0

| accepted

Answered

Control edge alpha via edge weights to visualize a dynamic network

You can set the LineStyle to be 'none' for edges that should not be displayed: >> g = digraph([3 1 2], [2 3 1], [0 0.5 1]); >>...

Control edge alpha via edge weights to visualize a dynamic network

You can set the LineStyle to be 'none' for edges that should not be displayed: >> g = digraph([3 1 2], [2 3 1], [0 0.5 1]); >>...

4 mois ago | 1

| accepted

Answered

how to create a symmetric Toeplitz matrix with bounds on eigenvalues?

You can use the MATLAB function toeplitz with one input argument (two-input returns a non-symmetric Toeplitz matrix).

how to create a symmetric Toeplitz matrix with bounds on eigenvalues?

You can use the MATLAB function toeplitz with one input argument (two-input returns a non-symmetric Toeplitz matrix).

4 mois ago | 0

Answered

Interpolation for n-dimensional array data

I don't think interpn would work very well for you: The U, S and V matrices returned by SVD are not linearly dependent on the in...

Interpolation for n-dimensional array data

I don't think interpn would work very well for you: The U, S and V matrices returned by SVD are not linearly dependent on the in...

4 mois ago | 1

Answered

eigs gives wrong eigenvalues

Edit: Please see the comment below, the first answer I gave here was going in the wrong direction. Thank you for the detailed d...

eigs gives wrong eigenvalues

Edit: Please see the comment below, the first answer I gave here was going in the wrong direction. Thank you for the detailed d...

4 mois ago | 2