scikit-learn/scikit-learn — pull request #2813 by arjoly (2014-02-01 12:20:22+00:00)
Title: [WIP] Faster random forest / extra trees by avoiding trying to split on constant features

If we find a constant features, we avoid trying to split later on it. This optimization is lightweight for `DepthFirstTreeBuilder`.

TODO list:
- [x] RandomSplitter
- [ ] BestSplitter
- [ ] Presort-bestsplitter?

For extra trees, I already got
```
$ (sklearn) ± python benchmarks/bench_covertype.py --classifier=ExtraTrees --random-seed=0

Classifier train-time test-time error-rate
--------------------------------------------
master 90.2975s 0.3086s 0.0214
this branch 69.4262s 0.3143s 0.0209
```