CSE SYMPOSIUM KEYNOTE ADDRESS
SPEAKER: PROF. PAUL R. WOODWARD
Department of Astronomy
University of Minnesota, Minneapolis, MN
DATE: FRIDAY, April 18, 1997
TIME: 3:00 PM
PLACE: 335 Grainger Engineering Library
TITLE: Simulating Turbulent Fluid Flow on Clusters of Shared Memory
Machines
ABSTRACT
Nearly four years ago my colleagues and I at the University of Minnesota
collaborated with Silicon Graphics to build a prototype machine, a cluster
of 16 powerful, 20-processor shared memory machines (SMPs) which we called
the Challenge Array, to simulate homogeneous turbulence on a grid of over
a billion cells with our PPM gas dynamics code. For this experiment, we
restructured our code to exploit the shared memory inside each cluster
member while passing messages between the SMPs as in a distributed memory
machine. By now, this hardware configuration, the SMP cluster, has
entered the supercomputing mainstream, especially at national centers
like NCSA and Los Alamos. However, the programming techniques which should
go along with this hardware are not yet in common practice. I will briefly
review the familiar methods for constructing multi-tasked parallel programs
for shared memory machines. Then I will suggest an approach to extending
these techniques over a cluster of SMPs, whether the cluster has distributed
shared memory (DSM) hardware support for such programs or not. Finally,
I will show some examples of calculations that my research group has carried
out on SMP clusters and indicate the still more exciting computations that
we expect to be supported by the new generation of these machines, like
those being acquired by NCSA.
BIOGRAPHY
Paul R. Woodward was born on August 25, 1946, in Rockeville Centre, New
York. He received a B.A. in Mathematics and Physics from Cornell
University in 1967 and a Ph.D. in Physics from the University of
California, Berkeley, in 1973. He worked for many years at the Lawrence
Livermore National Laboratory before taking, in 1985, his present
position as Professor of Astronomy at the University of Minnesota.
Professor Woodward is a Fellow of the Minnesota Supercomputer Institute
and is Director of the University of Minnesota's Laboratory for
Computational Science and Engineering.
Professor Woodward's research has focussed on the exploration of
nonlinear phenomena in fluid dynamics through large-scale computer
simulations. He has worked principally on turbulent flows, and
especially in astrophysical contexts where the effects of compressi-
bility are important. A persistent theme in his work is the use of
computers to perform numerical experiments for fluid dynamical systems
where the governing laws of physics are understood but their
implications are not, due to the complexity of chaotic nonlinear
interactions which develop. To enhance the predictive power of these
experiments, Woodward has worked on the development of accurate
numerical techniques, the best known of which is the Piecewise-Parabolic
Method (PPM) for compressible gas dynamics. To make the results of the
experiments more easily understandable, Woodward has led the development
of powerful scientific visualization systems and software. His efforts
in scientific visualization have centered on the special problems
presented by the extremely large data sets which his numerical
experiments have produced.