Browsing by Author "Linford, John C."

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    Chemical Mechanism Solvers in Air Quality Models
    Zhang, Hong; Linford, John C.; Sandu, Adrian; Sander, Rolf (MDPI, 2011-09-01)
    The solution of chemical kinetics is one of the most computationally intensive tasks in atmospheric chemical transport simulations. Due to the stiff nature of the system, implicit time stepping algorithms which repeatedly solve linear systems of equations are necessary. This paper reviews the issues and challenges associated with the construction of efficient chemical solvers, discusses several families of algorithms, presents strategies for increasing computational efficiency, and gives insight into implementing chemical solvers on accelerated computer architectures.
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    Multilayered Heterogeneous Parallelism Applied to Atmospheric Constituent Transport Simulation
    Linford, John C.; Sandu, Adrian (Department of Computer Science, Virginia Polytechnic Institute & State University, 2008-10-01)
    Heterogeneous multicore chipsets with many levels of parallelism are becoming increasingly common in high-performance computing systems. Effective use of parallelism in these new chipsets constitutes the challenge facing a new generation of large scale scientific computing applications. This study examines methods for improving the performance of two-dimensional and three-dimensional atmospheric constituent transport simulation on the Cell Broadband Engine Architecture (CBEA). A function offloading approach is used in a 2D transport module, and a vector stream processing approach is used in a 3D transport module. Two methods for transferring incontiguous data between main memory and accelerator local storage are compared. By leveraging the heterogeneous parallelism of the CBEA, the 3D transport module achieves performance comparable to two nodes of an IBM BlueGene/P, or eight Intel Xeon cores, on a single PowerXCell 8i chip. Module performance on two CBEA systems, an IBM BlueGene/P, and an eight-core shared-memory Intel Xeon workstation are given.