Scalability studies of an implicit shallow water solver for the Rossby-Haurwitz problem

  • Authors:
  • Chao Yang;Xiao-Chuan Cai

  • Affiliations:
  • Institute of Software, Chinese Academy of Sciences, Beijing, P.R. China and Department of Computer Science, University of Colorado at Boulder, Boulder, CO;Department of Computer Science, University of Colorado at Boulder, Boulder, CO

  • Venue:
  • VECPAR'10 Proceedings of the 9th international conference on High performance computing for computational science
  • Year:
  • 2010

Quantified Score

Hi-index 0.00

Visualization

Abstract

The scalability of a fully implicit global shallow water solver is studied in this paper. In the solver a conservative second-order finite volume scheme is used to discretize the shallow water equations on a cubed-sphere mesh which is free of pole-singularities. Instead of using the popular explicit or semi-implicit methods in climate modeling, we employ a fully implicit method so that the restrictions on the time step size can be greatly relaxed. Newton-Krylov-Schwarz method is then used to solve the nonlinear system of equations at each time step. Within each Newton iteration, the linear Jacobian system is solved by using a Krylov subspace method preconditioned with a Schwarz method. To further improve the scalability of the algorithm, we use multilevel hybrid Schwarz preconditioner to suppress the increase of the iteration number as the mesh is refined or more processors are used. We show by numerical experiments on the Rossby-Haurwitz problem that the fully implicit solver scales well to thousands of processors on an IBM BlueGene/L supercomputer.