[ENH] OWLouvain: Ensure deterministic clustering

[pavlin-policar]

Issue

Fixes #3278.

Description of changes

Version 0.12 of python-louvain was just released and with it the random_state parameter, which was missing before. I've added the parameter to our wrapper and set the random_state to a fixed value in the widget, so the results are deterministic in the widget.

Includes

• Code changes
• Tests
• Documentation

[pavlin-policar]

I've also fixed the version to 0.12 because the API might change in the next version taynaud/python-louvain#23.

[janezd]

Fixing a version looks like a good idea (as anybody who just spent a day trying to find why tests suddenly fail would confirm), yet it may be better to fix problems as they come, instead of jumping a few versions at some later time and having to fix the whole heap then.

I would let it fail when the new version comes and just change the import name when it happens. But it would be a good idea to add a comment at the point where we'll have to rename the import.

[pavlin-policar]

I've removed the version from the requirements and added a note to the import.

[codecov]

Codecov Report

Merging #3492 into master will decrease coverage by 0.03%.
The diff coverage is 90%.

@@            Coverage Diff             @@
##           master    #3492      +/-   ##
==========================================
- Coverage   83.59%   83.55%   -0.04%     
==========================================
  Files         367      367              
  Lines       65570    65464     -106     
==========================================
- Hits        54814    54700     -114     
- Misses      10756    10764       +8

[codecov]

Codecov Report

Merging #3492 into master will increase coverage by <.01%.
The diff coverage is 90%.

@@            Coverage Diff            @@
##           master   #3492      +/-   ##
=========================================
+ Coverage   83.59%   83.6%   +<.01%     
=========================================
  Files         367     367              
  Lines       65570   65580      +10     
=========================================
+ Hits        54814   54827      +13     
+ Misses      10756   10753       -3