scikit-learn/scikit-learn — pull request #3880 by pprett (2014-11-24 21:30:52+00:00)
Title: Sparse input support for Gradient Boosting

adds sparse input support:

* Falls back to ``BestSparseSplitter``
* Holds data in both ``csc`` and ``csr`` format during fit (needs the latter just to call ``tree.apply`` to get the terminal leaf assignment).

Todo:

- [ ] more & better tests
- [ ] benchmarks
- [ ] review

cc @arjoly @jnothman @glouppe