Discussions on sklearn

[bonartm]

Hi Stefan (I saw your comment https://github.com/spicedacademy/datascience_source/issues/223#issuecomment-737381613),

for inspiration you maybe also want to have a look at these two issues/ pull requests from the sklearn project:

• NMF with missing data scikit-learn/scikit-learn#8447
• ENH add support to missing values in NMF scikit-learn/scikit-learn#8474

I think, the idea is, that you modify the loss function in such a way that it ignores missing entries.