fix: count_ratio on non overlapping partitions

[drodarie]

Describe the work done

Make sure the volume ratio computation depends on the relative cell instead of the target cell.

List which issues this resolves:

fix #885, #889

Tasks

• Added tests

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📚 Documentation preview 📚: https://bsb--886.org.readthedocs.build/en/886/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.97%. Comparing base (f1d26b2) to head (2405b8e).
Report is 30 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #886      +/-   ##
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+ Coverage   87.89%   88.97%   +1.08%     
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  Files         103      110       +7     
  Lines       13771    15141    +1370     
==========================================
+ Hits        12104    13472    +1368     
- Misses       1667     1669       +2     

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[Helveg]

This solution introduces breaking changes: the current implementation of count_ratio intentionally follows the local density of the related cell type. The break probably went unnoticed because tests for this feature are missing?

[Helveg]

Hmm, I think the previous version counted the related cell in the analogous chunk & voxelset intersect, and then multiplied the ratio. It seems your new code:

• Takes the global relation_count * ratio
• Then estimates the own count for the chunk

Is this strictly better? It seems like both might be valid use cases? Sometimes a user may want the density/count to be analogous to the cell type in the same chunk/voxels? Maybe it's better to deprecate count_ratio and introduce 2 new indication methods local_count_ratio and global_count_ratio?

We'd probably have to do the same for some of the density ratio methods then?

[drodarie]

My implementation is not better but IMHO more intuitive. For instance, let' s say you want to place 1 IO cell for every 2 PC, here these two cells would not be in overlapping partitions.
This previous use case (A) is legit but very specific, I think most users would use the second one (B). Hence my suggestion as a "fix".

From the user point of view the two strategies are very close so I would suggest to give B an additional boolean flag "intersect" so that we could keep A?

[Helveg]

Ok, since we have no spec or definition, or tests, we can consider your enhancement a "bugfix", in return, could you write docs about each of these indicator methods in this PR so that the behaviour is defined? :)

I think it would also be minimal effort to keep the existing logic in a new indicator method "local_count_ratio"? But it's not a hill I would die on if you just want to remove it.

[Helveg]

If you provide the text I will provide images 🤗