Portable Acceleration of Materials Modeling Software:CASTEP, GPUs, and OpenACC

In this article, we present work to port the CASTEP first-principles materials modeling program to accelerators using open accelerator (OpenACC). We discuss the challenges and opportunities presented by graphical processing units (GPU) architectures in particular, and the approach taken in the CASTEP OpenACC port. Whilst the port is still under active development, early performance results show that significant speed-ups may be gained, particularly for materials simulations using so-called "nonlocal functionals,"where speed-ups can exceed a factor of ten.