photo

Christine Tobler

MathWorks

Last seen: 3 jours il y a |  Actif depuis 2015

Followers: 0   Following: 0

Message

Spoken Languages:
English, French, German
Pronouns:
She/her
Professional Interests:
Graph and Network Algorithms, Linear Algebra, Quantum Computing, Automatic Differentiation

Statistiques

All
  • Thankful Level 2
  • Solver
  • Knowledgeable Level 5
  • 36 Month Streak
  • Pro
  • Revival Level 2
  • First Answer

Afficher les badges

Feeds

Afficher par

Réponse apportée
solving linear system with decomposition(A,'qr') and qr(A) produce different results
There are two reasons that the results don't match: 1) When the matrix is not full-rank, the QR-based solver in decomposition o...

3 jours il y a | 1

| A accepté

Réponse apportée
What is the most computationally efficient factorization of a matrix A?
Your solution is correct. Of the factorizations you know (PA=LU, the Choleski, SVD and the QR factorization), only LU and Chole...

26 jours il y a | 1

Réponse apportée
Improving Precision of Eigenvectors with Large Eigenvalues
The linked post is about a symmetric matrix, is this also your case? In that case (if issymmetric returns true for your matrix),...

environ un mois il y a | 2

| A accepté

Réponse apportée
Join Subgraphs into a new Graph
Here's a quick example based on a guess at how you would like to merge the graphs: G1 = graph(["A" "B" "C"], ["B" "C" "D"]); G...

environ un mois il y a | 1

| A accepté

Réponse apportée
how to increase node/edge separation within the layer in the layered graph?
You can access the XData and YData properties of the GraphPlot object returned by plot, to move the nodes further apart. Note i...

environ 2 mois il y a | 0

Réponse apportée
Nonorthogonal eigenvectors for general eigenvalue problem with eig() and eigs()
For simple eigenvalue problem A*x = lambda*x, the eigenvalues are real and the eigenvectors can form an orthogonal basis only if...

environ 2 mois il y a | 0

| A accepté

Réponse apportée
Name for adjancy-to-graph algorithm?
The graph object in MATLAB uses an internal data format that is very similar to a sparse adjacency matrix, so the construction o...

2 mois il y a | 0

| A accepté

Réponse apportée
Convert an image to a graph object
From a graph theory perspective (others may have better ideas from the image processing side), I would start by making a graph o...

2 mois il y a | 0

Réponse apportée
eigs with complex hermitian matrix, should I set opts.issym to 1?
This only matters if you pass in a function handle - if you pass in a matrix, EIGS detects if it's hermitian (real or complex) d...

2 mois il y a | 0

Réponse apportée
Cyclebasis function for graphs not working
Yes, cyclebasis returns a fundamental cycle basis, but not necessarily the one with the shortest cycle lengths. See the document...

3 mois il y a | 1

| A accepté

Réponse apportée
SVD computation time question
I'm not sure what causes the sharp change between iterations - I can reproduce roughly similar timings when I call svd with 3 ou...

3 mois il y a | 1

| A accepté

Réponse apportée
What is the residual defined in eigs?
The issue is likely that eigs doesn't use the residual as you describe it: The iterative algorithm used inside of eigs when comp...

4 mois il y a | 0

Réponse apportée
LU decomposition with 5 output arguments
As Matt says, the simplest is likely to just use decomposition object. In terms of how to solve a linear system, the doc page g...

4 mois il y a | 2

| A accepté

Réponse apportée
Proper Installation of Tensor Toolbox
Find the path the folder that defines the class you want to use. My guess is for Tucker this will be the ttensor class (but it's...

4 mois il y a | 0

Réponse apportée
Computing eigenvalues and eigenvectors of two symbolic matrices
eig does not support the two-input syntax for symbolic. For the call eig(B, A), if A is invertible you can instead solve eig(A\B...

4 mois il y a | 0

Réponse apportée
Stability analysis of a time dependent Lyapunov equation
The tensorprod function doesn't do what you are looking for here, that would be kron (short for Kronecker product). It also see...

5 mois il y a | 0

Réponse apportée
getting warning while using eigs on the matrices obtained from freefem++
If modifying the input sigma doesn't help, it's likely that for your call eigs(A, B, sigma, ...) the matrices are such that A - ...

5 mois il y a | 0

| A accepté

Réponse apportée
Trying to construct a filtered graph using pmfg function that uses the (MATLAB-BGL) library in MacBook.
The problem seems to be with the MatlabBGL FileExchange package and specifically with the .mex files that are being provided the...

5 mois il y a | 0

| A accepté

Réponse apportée
Can I get all of the shortest paths between all pairs of nodes in a Directed Graph in one function call
Using shortestpathtree in a loop over the starting node is the way to go. You can change the data format of the first output by ...

6 mois il y a | 1

Réponse apportée
Inconsistency between Matlab eig() function and Matlab generated C code eig() function
For code generation, the eig function doesn't have as many special-case treatments as the eig function in regular MATLAB. This m...

6 mois il y a | 2

| A accepté

Réponse apportée
How to control the curvature of each edge when drawing graph object?
The curvature of the edges in this plot aren't controllable. You could turn off the edges from the graph plot, and use the plot ...

7 mois il y a | 1

Réponse apportée
eigs function works slowly
A possible issue is that "largestreal" option works less towards the strengths of the EIGS algorithm than the default "largestab...

7 mois il y a | 0

Réponse apportée
Why is my parfor loop running slower than a regular for loop
The problem is likely that the cost of each iteration is still too small to warrant the start-up time of the parfor loop. You c...

7 mois il y a | 0

Réponse apportée
Quick method in solving symmetric linear equation
You can definitely use iterative methods such as pcg. The success of this usually depends on how well-conditioned your matrix is...

9 mois il y a | 1

Réponse apportée
doc QR decomposition error
Hi, As you can see here, R is an m by n matrix and Q is an m by m matrix in the default behavior of the qr function: A = randn...

9 mois il y a | 0

Réponse apportée
Replacing old version graphshortestpath with new shortestpath function
You can replace [ dist,path{1} ] = graphshortestpath( adjMatrix, 1, numel(newImg(:))); with [ path{1}, dist ] = shortestpath(...

10 mois il y a | 0

Réponse apportée
Eigenvalues and Eigenvector computation on extremely bad conditioned matrices
If the matrix P has rank 120 and its size is 160, you should expect 40 eigenvalues to be Inf - this is how singularities in the ...

10 mois il y a | 0

Réponse apportée
QR factorization of a low rank matrix
Let's start with computing a rank-2 approximation of a large matrix. In general, this would be done using the SVD, but if you kn...

10 mois il y a | 0

Réponse apportée
Can additional information be added to the directed graph plotting node 'tooltip'?
Yes, you can do this using the dataTipTextRow function: nodeNames = {'Node A', 'Node B', 'Node C', 'Node D', 'Node E', 'Node F'...

11 mois il y a | 0

| A accepté

Réponse apportée
computational complexity of svds
There is a recent function (introduced R2020b) called svdsketch, which is using randomized linear algebra. We recommend this for...

11 mois il y a | 0

Charger plus