Argonne National Laboratory

pTatin3D: High-Performance Methods for Long-Term Lithospheric Dynamics

TitlepTatin3D: High-Performance Methods for Long-Term Lithospheric Dynamics
Publication TypeConference Paper
Year of Publication2014
AuthorsMay, DA, Brown, J, Le Pourhiet, L
Conference NameSC'14
Conference LocationNew Orleans, LA
ISBN Number978-1-4799-5500-8
Other NumbersANL/MCS-P5175-0814_1
AbstractSimulations of long-term lithospheric deformation involve post-failure analysis of high-contrast brittle materials driven by buoyancy and processes at the free surface. Geody- namic phenomena such as subduction and continental rifting take place over millions year time scales, thus require efficient solution methods. We present pTatin3D, a geodynamics modeling package utilising the material-point-method for tracking material composition, combined with a multigrid finite-element method to solve heterogeneous, incompressible visco-plastic Stokes prob- lems. Here we analyze the performance and algorithmic tradeoffs of pTatin3D’s multigrid preconditioner. Our matrix-free geomet- ric multigrid preconditioner trades flops for memory bandwidth to produce a time-to-solution > 2× faster than the best available methods utilising stored matrices (plagued by memory bandwidth limitations), exploits local element structure to achieve weak scaling at 30% of FPU peak on Cray XC-30, has improved dynamic range due to smaller memory footprint, and has more consistent timing and better intra-node scalability due to reduced memory-bus and cache pressure.