Optimizing Extender Code for NCSX Analyses
Authors: M. Richman, S. Ethier, and N. Pomphrey
Abstract:
Extender is a parallel C++ code for calculating the magnetic field in the vacuum
region of a stellarator. The code was optimized for speed and augmented with
tools to maintain a specialized NetCDF database. Two parallel algorithms were examined.
An even-block work-distribution scheme was comparable in performance
to a master-slave scheme. Large speedup factors were achieved by representing the
plasma surface with a spline rather than Fourier series. The accuracy of this representation
and the resulting calculations relied on the density of the spline mesh. The
Fortran 90 module db access was written to make it easy to store Extender output
in a manageable database. New or updated data can be added to existing databases.
A generalized PBS job script handles the generation of a database from scratch.
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Download PPPL-4279 (pdf 308 Kb)
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