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O: Fachverband Oberflächenphysik

O 20: Theoretical methods I

O 20.2: Vortrag

Montag, 26. März 2012, 18:00–18:15, A 060

juRS - Massively Parallel Real-Space DFT Calculations — •Paul Baumeister, Daniel Wortmann, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich Germany

We present a new DFT tool developed in Jülich 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 thousand atoms with very flexible boundary conditions. The real-space treatment of wave functions, densities and potentials enable a simple, efficient and strong 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 over eigenvalues (bands). Hence, we exploit the local character of the Kohn-Sham equation and approximate the kinetic energy operator with a localized high-order finite difference stencil. The extremely sparse Hamiltonian favours iterative diagonalization schemes. We will discuss the difficulties due the interplay of wave function convergence and density convergence. Further, we will demonstrate the efficiency of the parallelization on massively parallel supercomputer architectures such as IBM’s BlueGene which support cartesian nearest neighbor communication on the hardware level.