Talk abstract:
RSL: A Parallel Runtime System Library for Atmospheric Models
with Nesting
John Michalakes, Argonne National Laboratory
Limited area models of the atmosphere for weather forcasting
and climate prediction are computationally intensive applications
that can benefit the high performance and large memories of
scalable distributed memory parallel computers. The models typically
employ explicit finite-differencing methods for advection and
diffusion and are readily amenable to stencil-library approaches
for parallelization. Mesh refinement proveides the ability to
focus higher resolution computaion over a subdomain of interest
to resolve, for example, the effects of complicated terrain.
Parallelization of multiple nested domains requires addtional
services form a parallelization library for the conveyance of
forcing and feedback data between a parent and nested domain,
both decomposed over processors. Finally, the efficient implementaion
of these models requires attention to load imbalances.
RSL[1] is a parallel library developed at Argonne National
Laboratory that is tailored to regular-grid atmohpheric meodels
with nesting. It is similar to effors of a number or othr groups[2][3][5].
It provides high-level stencil and inter-domain communication,
irregualr domain decomposition, automatic local/global index
translation, distributed I/O, and dynamic load balancing. RSL
was used with Fortran90 to parallelize a well-known and widley
used regional weither model, the Penn State/NCAR Mesoscale Model
(MM5)[1]. Scaling and performance data on the IBM SP2 is presented,
along eith data showing the effectiveness of using RSL to implement
dynamic load balancin in the model (Figure 1).
REFERENCES
[1] G. A. Grell, J. Dudhia, and D.R. Stauffer, A Description
of the Fifth-Generation Penn State/NCAR Mesoscale Model (MM5),
Tech. Rep. NCAR/TN-398+STR, National Center for Atmospheric
Research, Boulder, Colorado, June 1994.
[2] R. Hempel and H. Ritzdorf, The GMD communications library
for grid -oriented problems, Tech. Rep. GMD-0589, German
National Research Center for Information Technology, 1991.
[3] S. R. Kohn and S. B. Baden, A Parallel Software Infrastructure
for Structured Adaptive Mesh Methods, in Proceedings of
Supercomputing `95, IEEE Computer Society Press, 1996.
[4] J. Michalakes, RSL: A Parallel Runtime System Library
for Regular Grid Finite Difference Models Using Multiple Nests,
Tech. Rep. ANL/MCS-TM-197, Mathematics and Computer Science
Division, Argonne National Laboratory, Argonne, Illinois, December
1994.
[5] B. Rodriguez, L. Hart, and T. Henderson, A Library
for the Portable Parallelization of Operational Weather Forcast
Models, in Coming of Age: Proceeding of the Sixth ECMWF
Workshop on the Use of Parallel Processors in Meteorology, World
Scientific, River Edge, NJ, 1995. pp. 148-161.
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Schedule
1996-1997
Mathematics in High Performance Computing
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