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PRODID:-//Microsoft Corporation//Outlook MIMEDIR//EN
VERSION:1.0
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DTSTART:20151118T200000Z
DTEND:20151118T203000Z
LOCATION:18CD
DESCRIPTION;ENCODING=QUOTED-PRINTABLE:ABSTRACT: High-resolution climate simulations require tremendous computing resources. In the Community Earth System Model (CESM), the ocean model is computationally expensive for high-resolution grids and is the least scalable component for most production simulations. In particular, the modified preconditioned Conjugate Gradient, used to solve the elliptic system of equations in the barotropic mode, scales poorly at the high core counts. In this work, we demonstrate that the communication costs in the barotropic solver occupy an increasing portion of the total execution time as core counts are increased. To mitigate this problem, we implement a Chebyshev-type iterative method (CSI) in the ocean model, which requires fewer global reductions, and develop an effective block preconditioner based on the Error Vector Propagation (EVP) method. We demonstrate that CSI with EVP preconditioning improves the scalability of the ocean component and produces an ocean climate statistically consistent with the original one.
SUMMARY:Improving the Scalability of the Ocean Barotropic Solver in the Community Earth System Model
PRIORITY:3
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