Pylearn2 is a machine learning library. Most of its functionality is built on top of Theano. This means you can write Pylearn2 plugins (new models, algorithms, etc) using mathematical expressions, and Theano will optimize and stabilize those expressions for you, and compile them to a backend of your choice (CPU or GPU).
Official git repository is at https://github.com/lisa-lab/pylearn2
git clone https://github.com/lisa-lab/pylearn2.git
and my clone with things not (yet) merged into main repo can be cloned with:
git clone https://github.com/TNick/pylearn2.git
The library is research-oriented, so you mind find it dificult to get it to work with your own dataset or to get it to work at all.