scikit-learn/scikit-learn — pull request #1405 by amueller (2012-11-24 20:06:23+00:00)
Title: WIP add chi2 and exponentiated chi2 kernel.

Basically a cython version of some of #1387.
Includes an exponentiated and non-exponentiated version.

This is a slightly different version of the chi2 kernel than in #1387, but I think they are equivalent. My version is based on [sminchisescu et al](http://sminchisescu.ins.uni-bonn.de/code/libsvm-chi2.html) and [fulkerson et al (pdf)](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.150.4613&rep=rep1&type=pdf).

Todo:
Docs and Test.