http://www.theregister.co.uk/2013/03/27/real_time_full_motion_mri/"In working through multi-GPU optimisation, they realized that they needed a multi-GPU programming library. So they built one, and now its available to the world. It allows users to write identical code to run on one, two, four or more GPUs and according to the researchers, it just works. (You can find the open-source library here.)"