This article is about a year old by now. Since then, a significant amount of progress has been made. Full details are available in this research paper published

This article is about a year old by now. Since then, a significant amount of progress has been made. Full details are available in this research paper published at the HIPS conference this year. http://www.cs.indiana.edu/~eholk/papers/hips2013.pdf http://www.cs.indiana.edu/~eholk/papers/hips2013.pdf This describes in some detail how they used the PTX backend and linked the host and GPU to perform matrix operations and so forth. Awesome stuff!