[BUG, ENH] Implement BFS m-separation algorithm

[jaron-lee]

…tion

Signed-off-by: Jaron Lee [email protected]

Fixes #47

Changes proposed in this pull request:

• Re-implements m-separation using a breadth first search method (see http://arxiv.org/abs/1803.00116) adapted from BayesBall (https://arxiv.org/ftp/arxiv/papers/1301/1301.7412.pdf that is O(m + n) for m edges, n nodes
• Add additional tests to cover m-separation statements involving all three (undirected, directed, bidirected) edges

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[codecov-commenter]

Codecov Report

Merging #48 (00fe4ad) into main (35e860c) will increase coverage by 0.08%.
The diff coverage is 98.36%.

@@            Coverage Diff             @@
##             main      #48      +/-   ##
==========================================
+ Coverage   68.90%   68.98%   +0.08%     
==========================================
  Files          27       27              
  Lines        2029     2038       +9     
  Branches      497      510      +13     
==========================================
+ Hits         1398     1406       +8     
  Misses        526      526              
- Partials      105      106       +1     

Impacted Files	Coverage Δ
..._graphs/networkx/algorithms/causal/m_separation.py	98.68% <98.36%> (-1.32%)	⬇️

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[adam2392]

Pretty much LGTM and appreciate the extra unit test cases.

Just some nits on the documentation.

[adam2392]

Just for the networkx sake, in case we can get this function into their package, perhaps we can add a short description of how the algorithm works and perhaps the big-O runtime.

[jaron-lee]

Added!

[adam2392]

Thanks @jaron-lee !