Technology and Engineering
  • ISSN: 2333-2581
  • Modern Environmental Science and Engineering

A Thread Parallel Sparse Matrix Chemistry Algorithm for the Community Multiscale Air Quality Model


George Delic

HiPERiSM Consulting, LLC, USA


Abstract: This reports on integration of a new Chemistry Transport Model (CTM) sparse matrix algorithm (FSPARSE) as a replacement of the legacy JSPARSE algorithm in the U.S. EPA Community Multiscale Air Quality (CMAQ) model. This has been implemented in both Rosenbrock and Gear methods for aqueous chemistry in a hybrid MPI and OpenMP implementation. Both methods are well suited for an OpenMP thread-parallel version. For a 24 hour scenario, execution performance results for both MPI and OpenMP thread parallel scaling are presented with the CMAQ5.3b release on a heterogeneous cluster of 10 nodes with a total of 128 cores. The FSPARSE version of CMAQ typically provides significant speedup over the standard EPA release with similar precision in predicted species concentration values.


Key words: air quality models, sparse matrix methods, MPI, OpenMP, rosenbrock solver, gear solver




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