2 ACuTEMan: A multigrid-based mantle convection simulation code and its optimization to the Earth Simulator

Abstract We report the current status of our numerical simulation code named “ACuTEMan ” for large-scale mantle convection problems on the Earth Simulator. The ACuTEMan code comes out from a newly-devel-oped “ACuTE ” algorithm, which solves the flow field of mantle convection in combination with the multi-grid method. This algorithm iteratively solves the steady-state equations for conservation of mass and momentum for highly viscous and incompressible fluids, and is proved to be suitable for mantle convection problems with excellent vector and parallel capability. In addition, a careful adaptation of the multigrid proce-dure enabled us to obtain a moderate parallel efficiency using up to 64 processor nodes of the Earth Simulator. In this paper we present the optimization and the performance of our method applied to mantle convection problems in a three-dimensional rectangular domain, with special emphasis on the enhancement of parallel efficiency of multigrid procedures by an “agglomeration ” technique