Optimise PC regression

[mumichae]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 97.61905% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 59.00%. Comparing base (9c5a936) to head (344fb75).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #408      +/-   ##
==========================================
+ Coverage   54.60%   59.00%   +4.39%     
==========================================
  Files          22       22              
  Lines        1683     1705      +22     
==========================================
+ Hits          919     1006      +87     
+ Misses        764      699      -65     

Flag	Coverage Δ
unittests	59.00% <97.61%> (+4.39%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
scib/metrics/cell_cycle.py	89.58% <100.00%> (+0.22%)	⬆️
scib/preprocessing.py	18.95% <100.00%> (ø)
scib/metrics/pcr.py	91.11% <97.05%> (+9.95%)	⬆️

... and 2 files with indirect coverage changes

[VladimirShitov]

Overall, looks super nice. Sometimes, the code is unclear. I left some comments on potential improvements :)

[VladimirShitov]

Looks great to me :)