By Ian Foster
My esteemed Grid Gurus moderator, Rich Wellner, asked "what is the most creative use for grid technology that you've ever seen?" This is a difficult question to answer, but I will attempt to do so anyway.
I choose the work of George Karniadakis, Suchuan Dong, Nick Karonis, and their colleagues on modeling blood flow in the human body. Why I like it is the wacky (sorry, wonderful) way in which they mapped this apparently highly tightly coupled problem onto the distributed sites of the NSF TeraGrid. Quoting one of their papers:
Motivated by a grand-challenge problem in biomechanics, we are striving to simulate blood flow in the entire human arterial tree. The problem originates from the widely accepted causal relationship between blood flow and the formation of arterial disease such as atherosclerotic plaques. These disease conditions preferentially develop in separated and recirculating flow regions such as arterial branches and bifurcations. Modeling these types of interactions requires significant compute resources to calculate the three-dimensional unsteady fluid dynamics in the sites of interest. Waveform coupling between the bifurcations, however, can be reasonably modeled by a reduced set of one-dimensional
equations that capture the cross-sectional area and sectional velocity properties. One can therefore simulate the entire arterial tree using a hybrid approach based on a reduced set of one-dimensional equations for the overall system and detailed 3D Navier-Stokes equations at arterial branches and bifurcations.
In other words, they mapped different parts of the human body (chest, legs, arms, head, and their arterial branches) to different TeraGrid sites, linking them by a simple, non-communication intensive 1-D problem.
The tools used to make this happen were MPICH-G2 (recently renamed as MPIG) and of course Globus.
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