Theano is a Python library that allows you to define, optimize, and evaluate symbolic mathematical expressions involving multi-dimensional arrays efficiently. Theano features:
Theano has been powering large-scale computationally intensive scientific investigations since 2007. But it is also approachable enough to be used in the classroom (IFT6266 at the University of Montreal).
We mainly use it for machine learning, but we are interested in broadening the user community. Feel free to join our mailing list, and try it out.
Also, check out the Deep Learning Tutorials that we're writing. They are a more of a "work in progress", but they demonstrate how to implement various sorts of neural networks (e.g. RBMs, DBNs, Convolutional networks, Stacked denoising autoassociators) and do machine learning experiments with them.