scikit-learn/scikit-learn — comment on commit 872e70d9b715be074aa761cbd9c40e29afd64d4f
File:  line 0
By larsmans:

The problem is in line 166, specifically the expression `X + self.skewedness`. If `self.skewedness != 0`, that produces an entirely dense matrix of dimensions `X.shape` in the worst case, and in a very inefficient way. There might be a way to make this work, but it will require a different way of adding in the skewedness. Since sparse input wasn't advertised, I decided to just make it impossible for now.