Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 22: Theoretical methods
O 22.4: Vortrag
Montag, 14. März 2011, 18:00–18:15, WIL C107
Massively Parallel Real-Space DFT Calculations — •Paul Baumeister1, Daniel Wortmann1, Tomoya Ono2, and Stefan Blügel1 — 1Peter Grünberg Institut & Institute for Advanced Simulation, Forschungzentrum Jülich and JARA, 52425 Jülich, Germany — 2Dept. of Precision Engineering, Osaka University, Osaka, Japan
We present a new DFT tool developed in Jülich and Osaka that combines equidistant real-space grids and the Projector Augmented Wave (PAW) method. The code is explicitly designed for the structural relaxation of systems consisting of several thousands of atoms with very flexible boundary conditions. The specific advantage of our approach lies in the possibility to achieve a high degree of parallelization. The real-space treatment of wave functions, densities and potentials enables a simple and efficient parallelization with respect to communication and load balancing. Besides the parallel computation of k-points, we employ a domain decomposition to the real-space cell and a parallelization of eigenvalues (bands). Hence, we exploit the local character of the Kohn-Sham equation and approximate the kinetic energy operator by finite differences, avoiding Fourier transforms completely. The arising communication pattern suits perfectly the data network of IBMs BlueGene type massively parallel supercomputers. We will discuss the challenges of band parallelization, in which communication cannot be avoided as much as in k-points or even the real-space domain decomposition. Besides the demonstration of the efficiency of the parallelization, we will also report on the obtainable accuracy.