Risposto

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:...

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 mesi fa | 1

Risposto

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 ...

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 mesi fa | 1

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Risposto

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. ...

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 mesi fa | 1

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Risposto

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...

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 mesi fa | 0

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Risposto

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...

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 mesi fa | 1

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Risposto

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...

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...

circa un anno fa | 1

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Risposto

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...

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...

circa un anno fa | 2

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Risposto

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...

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...

circa un anno fa | 0

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Risposto

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...

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...

circa un anno fa | 3

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Risposto

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...

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...

circa un anno fa | 0

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Risposto

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...

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...

circa un anno fa | 0

Risposto

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 ...

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 ...

circa un anno fa | 1

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Risposto

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...

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...

circa un anno fa | 1

Risposto

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...

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...

circa un anno fa | 2

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Risposto

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...

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...

circa un anno fa | 1

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Risposto

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...

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...

circa un anno fa | 0

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Risposto

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...

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...

circa un anno fa | 0

Risposto

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...

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...

circa un anno fa | 1

Risposto

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...

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...

circa un anno fa | 0

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Risposto

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...

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...

circa un anno fa | 0

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Risposto

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...

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...

circa un anno fa | 2

Risposto

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...

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...

oltre un anno fa | 1

Risposto

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...

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...

oltre un anno fa | 0

Risposto

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...

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...

oltre un anno fa | 1

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Risposto

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...

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...

oltre un anno fa | 0

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Risposto

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 ...

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 ...

oltre un anno fa | 0

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Risposto

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...

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...

oltre un anno fa | 0

Risposto

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 ...

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 ...

oltre un anno fa | 0

Risposto

How to get a Table Contents in Live Script .mlx export to HTLM

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 ...

How to get a Table Contents in Live Script .mlx export to HTLM

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 ...

oltre un anno fa | 0

Risposto

How is SVDS execution time related to the target rank?

So the goal of svds is usually to compute a requested rank that is much smaller than either size of the input matrix. A search s...

How is SVDS execution time related to the target rank?

So the goal of svds is usually to compute a requested rank that is much smaller than either size of the input matrix. A search s...

oltre un anno fa | 0

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