Tuesday,
November 24, 12:00 p.m. ECG 317
Richard Archibald
Oak Ridge National Labs
Time Acceleration Methods for the Shallow Water Equations on the Cubed Sphere
Abstract
Climate simulation will not grow to the ultrascale without new
algorithms to overcome the scalability barriers blocking existing
implementations. Until recently, climate simulations concentrated on
the
question of whether the climate is changing. The emphasis is now
shifting to impact assessments, mitigation and adaptation strategies,
and regional details. Such studies will require significant increases
in spatial resolution and model complexity while maintaining adequate
throughput. The barrier to progress is the resulting decrease in time
step without increasing single-thread performance. In this paper we
demonstrate how to overcome this time barrier for the standard tests
defined for the shallow-water equations on a sphere. This paper
explains
how combining a multiwavelet discontinuous Galerkin method with exact
linear part time-evolution schemes can overcome the time barrier for
advection equations on a sphere. The discontinuous Galerkin method
is a
high-order method that is conservative, flexible, and scalable. The
addition of multiwavelets to discontinuous Galerkin provides a
hierarchical scale structure that can be exploited to improve
computational efficiency in both the spatial and temporal dimensions.
Exact linear part time-evolution schemes are explicit schemes that
remain stable for implicit-size time steps.
