Seminar to be offered: "Partitioning with space-filling curves on the cubed-sphere"

John Dennis

SCD's Computational Science Section (CSS) will sponsor a seminar on Friday, 11 April 2003, at 10:30 a.m. in Suite 150 of NCAR's Mesa Laboratory. John Dennis, a CSS software engineer, will give the seminar, entitled "Partitioning with space-filling curves on the cubed-sphere."

Solving partial differential equations arising in geophysical fluid dynamics on distributed memory computers requires partitioning of the computational domain.

The choice of partitioning algorithm can have a significant impact on the sustained floating-point execution rate of a prototype atmospheric model. The NCAR spectral element model employs a gnomonic projection of a cube onto the surface of the sphere.

The six cube faces are subdivided into an array of quadrilateral spectral element. When the cubed-sphere is partitioned using METIS, both load imbalance and communication requirements leads to suboptimal performance.

Hilbert and Peano space-filling curves are investigated as alternative partitioning algorithms. The resulting partitions allow a maximum 22% increase in the sustained floating-point execution rate versus METIS on 768 processors of the IBM P690 cluster.

For more information, contact Jennifer DeLaurant at 303-497-1263, delauran@ucar.edu.