The most CPU-intensive part of obtaining the polarization potential in the Distributed Positron Model (DPM) or the Better Than Adiabatic Dipole (BTAD) model involves the calcuation of the Modified-Nuclear-Attraction integrals (V^NAI). It is necessary for the general case to obtain these integrals via direct 3-dimensional quadrature.

The computation of individual integrals can be efficiently performed on Vector or SIMD-parallel platforms. However, the most efficient way to compute the entire set of integrals makes use of a matrix quadrature scheme suggested by Dr. Carl Winstead. This method can make use of coded BLAS routines and (assuming adequate memory) is scalable from one to many nodes, with each processor computing a partial sum based on the number of quadrature points assigned.

A comparison between our Beowulf cluster (Gamera) and the campus SGI Origin 2000 cluster is available here.

To find out more about one of the most exciting developments in affordable parallel computing, see the page of Beowulf links maintained by Lee Burnside.

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