We report optimization work made in support of the development of a realtime Superfacility workflow between DIII-D and NERSC. At DIII-D, the ion properties measured by charge exchange recombination (CER) spectroscopy are required inputs for a Superfacility realtime workflow that computes the full plasma kinetic equilibrium. In this workflow, minutes matter since the results must be ready during the brief 10-15 minute pause between plasma discharges. Prior to this work, a sample CERFIT analysis took approximately 15 minutes. Because the problem consists of many calculations that can be done independently, we were able to restructure the CERFIT code to leverage this parallelism with Slurm job arrays. We reduced the runtime to approximately 51 seconds -- a speedup of roughly 20x, saving valuable time for both the scientists interested in the CER results and also for the larger equilibrium reconstruction workflow.
@article{arxiv.2309.08687,
title = {Speeding up charge exchange recombination spectroscopy analysis in support of NERSC/DIII-D realtime workflow},
author = {Aarushi Jain and Laurie Stephey and Erik Linsenmayer and Colin Chrystal and Jonathan Dursi and Hannah Ross},
journal= {arXiv preprint arXiv:2309.08687},
year = {2023}
}
Comments
8 pages, 5 figures. Not a preprint- this work was rejected from a conference proceedings, so arXiv will hopefully be the final home Updated to add arXiv link/DOI to header of paper