Optimization of the gyroaverage operator based on hermite interpolation

Abstract : Gyrokinetic modeling is appropriate for describing Tokamak plasma turbulence, and the gyroaverage operator is a cornerstone of this approach. In a gyrokinetic code, the gyroaveraging scheme needs to be accurate enough to avoid spoiling the data but also requires a low computation cost because it is applied often on the main unknown, the 5D guiding-center distribution function, and on the 3D electric potentials. In the present paper, we improve a gyroaverage scheme based on Hermite interpolation used in the Gysela code. This initial implementation represents a too large fraction of the total execution time. The gyroaverage operator has been reformulated and is now expressed as a matrix-vector product and a cache-friendly algorithm has been setup. Different techniques have been investigated to quicken the computations by more than a factor two. Description of the algorithms is given, together with an analysis of the achieved performance.
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https://hal.inria.fr/hal-01261427
Contributor : Fabien Rozar <>
Submitted on : Friday, February 5, 2016 - 3:48:36 PM
Last modification on : Thursday, February 7, 2019 - 2:37:33 PM
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  • HAL Id : hal-01261427, version 1
  • ARXIV : 1602.02886

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Fabien Rozar, Christophe Steiner, Guillaume Latu, Michel Mehrenberger, Virginie Grandgirard, et al.. Optimization of the gyroaverage operator based on hermite interpolation. Jul 2014, Luminy, France. 2014, ⟨http://smai.emath.fr/cemracs/cemracs14/⟩. ⟨hal-01261427⟩

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