Added Stochastic Variability in Community Detection Algorithms

[SKG24]

Used Chatgpt for understanding the functions and theory around the mathematical process.

• By submitting this pull request, I assign the copyright of my contribution to The igraph development team.

At first run:

At second run:

This supports stochastic method might give wildly different answers on a network without any significant community structure, while it gives consistent answers on one that has obvious communities.

Since the number of iterations is set to 50, even in structured graphs, slight variations in similarity scores may be observed.

[szhorvat]

I won't have time to look in detail today, but I checked whether the docs build with this change, and unfortunately they do not. Can you please check if you can fix this? You can build the docs using scripts/mkdoc.sh -c.

[SKG24]

Issue Description:
The script mkdoc.sh -c fails with the following error:

AttributeError: module 'igraph' has no attribute '_igraph'. Did you mean: 'Graph'?
This issue is persistent even after:

• Reinstalling python-igraph
• Passing clustering objects instead of membership lists in compare_communities()
• Ensuring the same code works in Google Colab

[ntamas]

I think I've fixed the build issue in the main branch; please try again and let me know if it still doesn't work.

[SKG24]

Thank you! It worked.

Screen.Recording.2025-03-27.at.9.33.28.PM.mov

[szhorvat]

This is a nice illustration!

I left a few comments for improvement.

Please remove changes to the sg_execution_times.rst file. This file was likely committed by accident, and I think we should remove it (but not as part of this PR).

[SKG24]

I have made the suggested changes.

Screen.Recording.2025-03-28.at.3.38.52.PM.mov

[SKG24]

This is a nice illustration!

I left a few comments for improvement.

Please remove changes to the sg_execution_times.rst file. This file was likely committed by accident, and I think we should remove it (but not as part of this PR).

Should I directly delete this file from PR through files changed section?

[szhorvat]

Should I directly delete this file from PR through files changed section?

Yes, that would be fine.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 14 days if no further activity occurs. Thank you for your contributions.

[szhorvat]

Continued in #840. I can't push to this as the work was done on the main branch instead of a separate branch.