Community Profile

Christine Tobler

MathWorks

219 2015 年以降の合計貢献数

Professional Interests: numerical linear algebra, graph algorithms

Christine Tobler's バッジ

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...

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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...

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...

3日 前 | 0

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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 ...

11日 前 | 1

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...

14日 前 | 0

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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 ...

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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...

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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...

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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...

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

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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 ...

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...

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...

2ヶ月 前 | 0

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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...

2ヶ月 前 | 0

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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...

2ヶ月 前 | 0

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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]); >>...

2ヶ月 前 | 1

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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).

2ヶ月 前 | 0

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...

3ヶ月 前 | 1

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...

3ヶ月 前 | 2

How can I solve linear equation system in parallel?
As John says, if you are using decomposition on one computer with several cores, the solver used already will use those cores if...

3ヶ月 前 | 1

Why Power of Matrix with decimal values gives really big numbers?
For a Markov Chain, you need the sum of each row to be 1 (as this represents the probability to transition to any state), and ev...

3ヶ月 前 | 0

Which Right Eigenvector to report?
The left and right eigenvectors are matched one-by-one. For example, for [V, D, W] = eig(A), the eigenvalue D(k, k) corresponds ...

3ヶ月 前 | 0

eigs for generalized eigenvalue problem ( [V,D] = eigs(A,B) ) with spars matrix
A bug was introduced in R2017b in eigs for matrices with exact zero eigenvalues. This bug has been fixed in R2019a, the fix appl...

4ヶ月 前 | 1

Error using eig Input matrix contains NaN or Inf from images
The variable covariance_matrix contains non-finite values (either Inf meaning infinity, returned for example from 1/0, or NaN me...

4ヶ月 前 | 0

Why are eigenvector matrices computed by matlab not idempotent
Hi Marco, You seem to be confusing two terms: A matrix M is idempotent if ; it's orthogonal if , which is what you are testing ...

4ヶ月 前 | 2

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Warning: Matrix is close to singular or badly scaled. Results may be inaccurate. RCOND = 7.252760e-17.
As lambda approaches an eigenvalue of A (which is the goal of your algorithm), the matrix A - lambda*eye(size(A)) becomes close ...

4ヶ月 前 | 1

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How to compute efficiently A^(-1)*(1-exp(-A*h))?
For most sparse matrices expm(A) will be dense, so that should be expected to be expensive with a 1e4-by-1e4 matrix. If you are ...

4ヶ月 前 | 0

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How to add svd(singular value decomposition) in a custom layer
When dlarray supports a function, this means, most of all, that it supports automatic differentiation of this function - which f...

4ヶ月 前 | 0

How to add svd(singular value decomposition) in a custom layer
Yes, this is because SVD is not supported for dlarray. For its first release in R2019b, dlarray supports about 80 basic methods,...

4ヶ月 前 | 0

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Open just some Graph Edges in Variable Editor and let the user modify them?
That's tricky: In terms of assignment, if G.Edges(i, :) is assigned to, the graph class interprets this as assigning to all elem...

5ヶ月 前 | 0

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