The GW method, which can describe accurately electronic excitations, is one of the most widely used ab initio electronic structure technique and allows the physics of both molecular and condensed phase materials to be studied. However, the applications of the GW method to large systems require supercomputers and highly parallelized software to overcome the high computational complexity of the method scaling as O(N 4 ). Here, we develop efficient massivelyparallel GW software for the plane-wave basis set by revisiting the standard GW formulae in order to discern the optimal approaches for each phase of the GW calculation for massively parallel computation. These best numerical practices are implemented into the OpenAtom software which is written on top of Charm++ parallel framework. We then evaluate the performance of our new software using range of system sizes. Our GW software shows significantly improved parallel scaling compared to publically available GW software on the Mira and Blue Waters supercomputers, two of largest most powerful platforms in the world.
Major research universities are grappling with their response to the deluge of scientific data emerging through research by their faculty. Many are looking to their libraries and the institutional repositories for a solution. Scientific data introduces substantial challenges that the document-based institutional repository may not be suited to deal with. The Sustainable Environment - Actionable Data (SEAD) Virtual Archive (VA) specifically addresses the challenges of ‘long tail’ scientific data. In this paper, we propose requirements, policy and architecture to support not only the preservation of scientific data today using institutional repositories, but also rich access to data and their use into the future.
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