Frederick H. Streitz

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We report the computational advances that have enabled the first micron-scale simulation of a Kelvin-Helmholtz (KH) instability using molecular dynamics (MD). The advances are in three key areas for massively parallel computation such as on BlueGene/L (BG/L): fault tolerance, application kernel optimization, and highly efficient parallel I/O. In particular,(More)
With supercomputers anticipated to expand from thousands to millions of cores, one of the challenges facing scientists is how to effectively utilize this ever-increasing number. We report here an approach that creates a heterogeneous decomposition by partitioning effort according to the scaling properties of the component algorithms. We demonstrate our(More)
We investigate solidification in tantalum and uranium systems ranging in size from 64,000 to 524,288,000 atoms on the IBM BlueGene/L computer at LLNL. Using the newly developed ddcMD code, we achieve performance rates as high as 103 TFlops, with a performance of 101.7 TFlop sustained over a 7 hour run on 131,072 cpus. We demonstrate superb strong and weak(More)
Blue Gene/L represents a new way to build supercomputers, using a large number of low power processors, together with multiple integrated interconnection networks. Whether real applications can scale to tens of thousands of processors (on a machine like Blue Gene/L) has been an open question. In this paper, we describe early experience with several physics(More)
Although computer simulation has played a central role in the study of nucleation and growth since the earliest molecular dynamics simulations almost 50 years ago, confusion surrounding the effect of finite size on such simulations has limited their applicability. Modeling solidification in molten tantalum on the Blue Gene/L computer, we report here on the(More)
DOI: 10.1177/1094342007085025 2008; 22; 33 International Journal of High Performance Computing Applications and Ümit Çatalyürek Chow McLendon, Bruce Hendrickson, Franz Franchetti, Stefan Kral, Jürgen Lorenz, Christoph W. Überhuber, Edmond Gygi, Timothy C. Germann, Kai Kadau, Peter S. Lomdahl, Charles Rendleman, Michael L. Welcome, William Alan Gara, John A.(More)
We use molecular dynamics (MD) to simulate diffusion in molten aluminum-copper (AlCu) alloys. The self-diffusivities and Maxwell-Stefan diffusivities are calculated for AlCu mixtures using the Green-Kubo formulas at temperatures from 1000 to 4000 K and pressures from 0 to 25 GPa, along with additional points at higher temperatures and pressures. The(More)
The temperature equilibration rate between electrons and protons in dense hydrogen has been calculated with molecular dynamics simulations for temperatures between 10 and 600eV and densities between 10;{20}cm;{-3}to10;{24}cm;{-3} . Careful attention has been devoted to convergence of the simulations, including the role of semiclassical potentials. We find(More)
We use classical molecular dynamics to investigate electron-ion temperature equilibration in a two-temperature SF6 plasma. We choose a density of 1.0 x 10;{19}SF_{6} molecules per cm;{3} and initial temperatures of T_{e} = 100 eV and T_{S} = T_{F} = 15 eV, in accordance with experiments currently underway at Los Alamos National Laboratory. Our computed(More)
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