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FAMOUS, faster: using parallel computing techniques to accelerate the FAMOUS/HadCM3 climate model with a focus on the ratiative transfer algorithm

Lookup NU author(s): Dr Hiro Yamazaki


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We have optimised the atmospheric radiation algorithm of the FAMOUS climate model on several hardware platforms. The optimisation involved translating the Fortran code to C and restructuring the algorithm around the computation of a single air column. A task queue and a thread pool are used to distribute the computation to several pro- cessors. Finally, four air columns are packed together in a single data structure and computed simultaneously using Single Instruction Multiple Data operations. The modified algorithm runs more than 50 times faster on the CELL’s Synergistic Pro- cessing Elements than on its main PowerPC processing element. On Intel-compatible processors, the new radiation code runs 4 times faster and on graphics processors, using OpenCL, more than 2.5 times faster, as compared to the original code. Because the radiation code takes more than 60 % of the total CPU time, FAMOUS executes more than twice as fast. Our version of the algorithm returns bit-wise identical results, which demonstrates the robustness of our approach.

Publication metadata

Author(s): Hanappe P, Beurive A, Laguzet F, Steels L, Bellouin N, Boucher O, Yamazaki YH, Aina T, Allen M

Publication type: Article

Journal: Geoscientific Model Development Discussions

Year: 2011

Volume: 4

Issue: 2

Pages: 1273-1303

Print publication date: 17/06/2011

ISSN (print): 1991-9611

ISSN (electronic): 1991-962X

Publisher: Copernicus GmbH


DOI: 10.5194/gmdd-4-1273-2011


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