Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 56: Focussed Session: Frontiers of Electronic Structure Theory - Non-equilibrium Phenomena at the Nano-scale V
O 56.7: Vortrag
Mittwoch, 2. April 2014, 18:00–18:15, TRE Ma
Strong Parallelization of Real-Space DFT Calculations — •Andrea Nobile1,2, Paul Baumeister1,2, Daniel Wortmann1, and Stefan Blügel1 — 1Peter Grünberg Institut & Institute for Advanced Simulation, Forschungzentrum Jülich and JARA, 52425 Jülich, Germany — 2Jülich Supercomputing Center, Forschungzentrum Jülich, 52425 Jülich, Germany
The rapid change in modern supercomputing architectures poses a challenge to well established DFT codes. In particular, the increase in raw floating point power obtained through parallelism at different levels is not easily exploitable by using the traditional direct diagonalization methods. We will present our new real-space Projector Augmented Wave (PAW) implementation. The real-space representation of the wave functions, densities and potentials, enables the usage of very flexible boundary conditions and naturally adapts to massively parallel architectures. Parallelism can be exploited in the form of domain decomposition of the three dimensional grid, k-point sampling and bands. The kinetic energy operator, realized as a finite difference stencil, is localized. As a consequence the real-space representation of the Hamiltonian is sparse. This limits the amount of necessary communications and allows an application of the operator to a trial vector in order(N) operations. We will present results about the efficiency of the most numerical intensive parts of the code and we will compare the accuracy of the calculations for reference systems with other established DFT methods.