[GSoC] Parallelisation of AnalysisBase with multiprocessing and dask

[marinegor]

Fixes #4158
Also fixes # 4259 as a check in AnalysisBase.run() no it doesn't, I'll do another PR that does that.

Related to #4158, does not help f-i-x-i-n-g (cudos to github bot) the issue per se but paves the way towards that.

Changes made in this Pull Request:

• several methods added analysis.base.AnalysisBase, implementing backend configuration, splitting of the frames for analysis, computation, and results aggregation
• module analysis.backends introduces BackendBase class, as well as built-in backends BackendMultiprocessing, BackendSerial and BackendDask, implementing the apply method for computations using various backends
• module analysis.results introduces ResultsGroup class that allows for merging of multiple uniform Results objects from the same module, given appropriate aggregation functions

PR Checklist

• Tests?
• Docs?
• CHANGELOG updated?
• Issue raised/referenced?

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📚 Documentation preview 📚: https://mdanalysis--4162.org.readthedocs.build/en/4162/

[github-actions]

Linter Bot Results:

Hi @marinegor! Thanks for making this PR. We linted your code and found the following:

Some issues were found with the formatting of your code.

Code Location	Outcome
main package	⚠️ Possible failure
testsuite	⚠️ Possible failure

Please have a look at the darker-main-code and darker-test-code steps here for more details: https://github.com/MDAnalysis/mdanalysis/actions/runs/10422317333/job/28866526863

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[codecov]

Codecov Report

Attention: Patch coverage is 97.10744% with 7 lines in your changes missing coverage. Please review.

Project coverage is 93.62%. Comparing base (d16b8d4) to head (1dc4613).
Report is 2 commits behind head on develop.

Files	Patch %	Lines
package/MDAnalysis/analysis/base.py	96.52%	2 Missing and 2 partials ⚠️
package/MDAnalysis/analysis/results.py	95.71%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           develop    #4162    +/-   ##
=========================================
  Coverage    93.61%   93.62%            
=========================================
  Files          171      173     +2     
  Lines        21254    21419   +165     
  Branches      3937     3978    +41     
=========================================
+ Hits         19897    20053   +156     
- Misses         898      903     +5     
- Partials       459      463     +4     

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[RMeli]

Great to see things are moving @marinegor!

I'll have a proper look at this PR when back from holidays, but I just wanted to point out that GitHub is not very smart, so "Does not fix #4162" will actually automatically close #4162 when this is merged. "Related to #4162" or something similar (with no "fix" before the PR number) would avoid this issue.

[orbeckst]

Good start. I left a few comments on the code.

[orbeckst]

@yuxuanzhuang any initial comments so that @marinegor can move forward?

[marinegor]

I added suggestions from @RMeli and @IAlibay (thanks a lot!), and opened issues for few non-critical ValueErrors raised here and there and noted by @IAlibay.

That's it for me, @orbeckst feel free to proceed!

[IAlibay]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[IAlibay]

Thanks!

Azure pipelines fails seem completely unrelated - I wouldn't let them be blockers

[IAlibay]

@orbeckst I'm letting you do the final call on merging.

[orbeckst]

Some minor fixes (which I will add) and a few where I need @marinegor to have a quick look (and update with the suggestions if ok).

[orbeckst]

@marinegor please check my two suggested changes. If they are ok, please add accept the suggestions or make appropriate changes yourself. Then ping me and assuming that CI still passes (at least non Azure) I will then finally squash-merge (while keeping the co-authors line with the reviewers).

[marinegor]

@orbeckst I agree with both of the changes, thanks. I removed the issubclass check that you added after the failing test, since it's only for classes and not for their instances.

Then ping me and assuming that CI still passes (at least non Azure)

ping!

I will then finally squash-merge (while keeping the co-authors line with the reviewers).

🤞🤞🤞

[p-j-smith]

Great work @marinegor! An excellent contribution to MDAnalysis

[orbeckst]

HOORAY!!!!

merged

[RMeli]

Wooooooah! 🥳

Congratulations and than you for the massive effort @marinegor! 🚀