Portable parallel programming for the dynamic load balancing of unstructured grid applications

The ability to dynamically adapt an unstructured grid (or mesh) is a powerful tool for solving computational problems with evolving physical features; however an efficient parallel implementation is rather difficult, particularly from the viewpoint of portability on various multiprocessor platforms. We address this problem by developing PLUM, an automatic and architecture-independent framework for adaptive numerical computations in a message-passing environment. Portability is demonstrated by comparing performance on an SP2, an Origin2000, and a T3E, without any code modifications. We also present a general-purpose load balancer that utilizes symmetric broadcast networks (SBN) as the underlying communication pattern, with a goal to providing a global view of system loads across processors. Experiments on an SP2 and an Origin2000 demonstrate the portability of our approach which achieves superb load balance at the cost of minimal extra overhead