|Name:||Algorithms & Analysis(2) Implementation & Application of Poisson Equation Parallel Solver Based on FFT & TDMA Direct Methods|
|Time:||Monday, June 17, 2013
1:30 PM - 1:35 PM
|Room:||Multi-Purpose Area 4 (MPA 4)
CCL - Congress Center Leipzig
|Speakers:||Ji-Hoon Kang, KISTI|
|Abstract:||We present a development of Poisson’s equation parallel solver for the direct numerical simulation (DNS) of incompressible flows. Two-level hybrid scheme combining MPI and OpenMP parallelization was implemented for the efficient use of our cluster supercomputer in which each computing node has multi-core CPUs. A data exchange scheme across the three-dimensionally decomposed MPI domains was developed to send and receive data using all-to-all communication. In each MPI task, a further shared memory parallelization was implemented using OpenMP directives. Three-dimensional FFT-based direct method was adopted to solve the discretized equation. To treat one unequal mesh direction often faced in turbulent simulations, tri-diagonal matrix algorithm was applied in the unequal mesh direction instead of FFT. The developed solver supports periodic, Dirichlet and Neumann boundary conditions using sine and cosine transform. The developed solver has been successfully tested up to 8192 cores for meshes with up to 200 billion grid points. Advantages and limitation for the additional OpenMP parallelization are presented and discussed in this paper. Several application examples of current solver are briefly presented to show the performance advantages over the original legacy code. The solver will be offered to interested users as the library PEPS, Poisson’s equation parallel solver.
Ji-Hoon Kang, KISTI; Kwang Jin Oh, KISTI