How to find all the downstream nodes from a node in a graph?
Looking at this again due to the recent comment added, it might be simpler to use a directed graph instead of an undirected one:...

11 maanden ago | 1

Which solver should I use to solve a square and symmetric, linear system of equations?
The first thing to check is the size and density of your matrix. The SYMMLQ function you mentioned is one of a group of methods ...

11 maanden ago | 1

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Can we compute the graph Laplacian matrix for a directed graph?
It depends how you want to define it, there is no one consistent definition of what the graph laplacian of a directed graph is. ...

11 maanden ago | 1

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eigs using 'smallestabs' vs scalar
Hi Jack, I had initially misunderstood that you were getting different results when passing in 'smallestabs' vs. passing in the...

12 maanden ago | 0

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missing eigenvector when using eig on defective matrix
The short answer is that this is a case where a small change in the input matrix has a large effect on the eigenvectors being co...

12 maanden ago | 1

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THE GRAPH FUNCTION DOESN'T CONSIDER WEIGHTS
Hard to say what's going wrong without seeing your code. Here's an example where you can see the weights being used to decide on...

ongeveer een jaar ago | 1

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mldivide (backslash): advantage by using sparse matrix instead of a full matrix with respect to the quality of the results?
The condition estimate used in mldivide to decide if a warning should be given is much less accurate for the sparse case. This i...

ongeveer een jaar ago | 2

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LDL does not support complex symmetric matrices
Largely the reason LDL doesn't support this is that it's less commonly requested for complex symmetric matrices than for complex...

ongeveer een jaar ago | 0

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Inconsistency in behavior of SVD
Firstly, I agree completely with John's great explanations above: Any singular value below eps*first singular value should be tr...

ongeveer een jaar ago | 3

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Accuracy Problem when solving linear equation system using: lu(S) vs. decomposition(S,'lu')
The version in decomposition does some optional steps of iterative refinement: It uses the same solution you have above based on...

ongeveer een jaar ago | 0

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Need help fixing errors on code written in old MATLAB syntax
I'd also recommend replacing the calls svd(A) and svd(A, 0) with calling svd(A, 'econ'), since the code here is only using the f...

ongeveer een jaar ago | 0

Different results on different computers, Matlab 2021b - 64 bit, windows 64 bit, both Intel chips
First, about "which value to trust?" Both values are equally trustworthy, the differences in results come down to applying the ...

ongeveer een jaar ago | 1

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eigs with Extended Capabilities
The first of these would only be useful if you need to apply EIGS to many problems in parallel, in which case each of these coul...

ongeveer een jaar ago | 1

How to parallelize many small SVD's on a GPU
As of R2021b, there is a function pagesvd which is supported on both CPU and distributed arrays. It's not supported for gpuArray...

ongeveer een jaar ago | 2

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How does shortestpath function work?
Every edge has a number, which is the order in which they appear in the Edges table (try displaying g.Edges). The edgepath conta...

ongeveer een jaar ago | 1

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Eigs passes the wrong StartVector
The standard method used in EIGS is only efficient for matrices that are quite large. When eigs detects that the input matrix is...

ongeveer een jaar ago | 0

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How to enhance the performance of Matalb's function sqrtm?
Not in general. You might be able to find a cheaper but less accurate way to compute this, but if that's acceptable would depend...

ongeveer een jaar ago | 0

fastest path between more than two nodes
To compute simply the shortest-path distance, you can use the distances function and pass in a graph object you've constructed u...

ongeveer een jaar ago | 1

Follow a complex eigenvalue in a spectrum at different times
You could try using the matchpairs function: rng default; d = randn(20, 1) + 1i*randn(20, 1); d2 = d + 0.1*(randn(20, 1) + 1i...

ongeveer een jaar ago | 0

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Error using eig in Matlab 2021b by using Parallels 17 of Macbook Pro (M1 )
Since MATLAB is trying to load a .dll file, I'm assuming you're running a Windows VM on this Macbook Pro. MATLAB doesn't support...

ongeveer een jaar ago | 0

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use of svds with function handles
The svds function needs to be able to apply both A*x and A'*x, so your function handle should accept a second input which is eit...

meer dan een jaar ago | 2

How to compute cholesky to all slice of a tensor?
There isn't another way to do this right now. We have functions that do other linear algebra operations to each page of an ND-ar...

meer dan een jaar ago | 1

Why does mldivide solve equations so fast that FORTRAN can't compare it？
MATLAB's mldivide uses multithreading. It doesn't use the GPU unless you have the Parallel Computing Toolbox and are using the g...

meer dan een jaar ago | 0

How to highlight single edges in an undirected graph?
Do you still want the multiple edges to be displayed? If not, you can use the simplify command to reduce all multiple edges to j...

meer dan een jaar ago | 1

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Unable to find out left eigen vectors of symbolic matrix
The left eigenvectors are still expressed as right eigenvectors of M', meaning they satisfy a slightly different equation: syms...

meer dan een jaar ago | 0

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Program to find connected and non-isomorphic graphs
In the last loop, you are checking if adj is isomorphic to any previous graph. If there is one graph that adj is not isomorphic ...

meer dan een jaar ago | 0

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How can I invert a big matrix e.g. 1000-by-1000
When running inv on this matrix, there's a warning: >> M = inv(current_Fit_Mat); Warning: Matrix is close to singular or badly...

meer dan een jaar ago | 0

Add an automatic TOC to an .mlx
You can go the "Insert" tab (just to the right of where it says "Live Editor" on top of the MATLAB window) and there's a button ...

meer dan een jaar ago | 0