Tagged Questions
2
votes
0answers
56 views
Fast calculation of commute distances on large graphs (i.e. fast computation of the pseudo-inverse of a large Laplacian / Kirchhoff matrix)
I have a large, locally connected and undirected graph $G$ with $\approx 10^4$ vertices and $\approx 10^5$ to $\approx 10^6$ edges. Moreover I can bound the maximum vertex degree as $Q_{max}$. I ...
1
vote
1answer
85 views
Weighted Kirchhoff Matrix?
I have a weighted graph and I want its graph Laplacian matrix (what Mathematica calls the Kirchhoff matrix in the unweighted case). Is there an easy way to get this?
For example, the command:
...
1
vote
2answers
85 views
How do I divide the columns of a matrix by the sum of its elements?
I am trying to create a transition matrix for a network. In order to do this, I need to sum down the column (the out degree), and then divide the column by the out degree in order to normalize it.
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5
votes
2answers
798 views
Eigenvalue / Eigenvector Calculation
I'm currently trying to compute the three smallest eigenvectors for a 34 by 34 matrix. While I was expecting this to take some time, Mathematica has been running for the past 3 hours, which seems ...
6
votes
1answer
241 views
How to turn a random graph into a matrix
I have constructed a random graph with Mathematica using the RandomGraph command. Now I would like to convert this graph to a matrix, but I don't know how. The ...
19
votes
1answer
915 views
Is there a way to convert an image into a Graph?
I'm trying to convert an image with several overlapping dots into a Graph. The goal is to be able to derive the Kirchhoff matrix for the randomly created "network ...
18
votes
2answers
943 views
Cycles of length N in a graph
If I have an undirected graph represented with an adjacency matrix, how can I find all the subgraphs which are a cycle of length N?
I don't really know the math nor the programming language well, so ...
