scikit-learn/scikit-learn — pull request #515 by ogrisel (2011-12-24 23:25:54+00:00)
Title: MRG: support for variance scaling on CSR matrices

Leverage @mblondel's work on Cython utility to compute mean and variance of CSR matrix to reuse it in the `sklearn.preprocessing` module for variance scaling.

Also move cython code from `sklearn.preprocessing` to `sklearn.utils.sparsefuncs`.