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DTSTART:19700308T020000
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BEGIN:VEVENT
DTSTAMP:20211207T055405Z
LOCATION:Online
DTSTART;TZID=America/Chicago:20211119T092000
DTEND;TZID=America/Chicago:20211119T094000
UID:submissions.supercomputing.org_SC21_sess334_ws_lasalss101@linklings.co
 m
SUMMARY:Iterative Methods with Mixed-Precision Preconditioning for Ill-Con
 ditioned Linear Systems in Multiphase CFD Simulations
DESCRIPTION:Workshop\n\nIterative Methods with Mixed-Precision Preconditio
 ning for Ill-Conditioned Linear Systems in Multiphase CFD Simulations\n\nI
 na, Idomura, Imamura, Yamashita, Onodera\n\nA new mixed-precision precondi
 tioner based on the iterative refinement (IR) method is developed for the 
 preconditioned conjugate gradient (P-CG) solver and the multigrid precondi
 tioned conjugate gradient (MGCG) solver in the multi-phase thermal-hydraul
 ic CFD code JUPITER. In the IR preconditioner, mixed-precision computing i
 s designed to avoid influences of the roundoff errors in computing ill-con
 ditioned matrices. Linear systems are normalized within the dynamic range 
 of FP16. All data is stored in FP16 to reduce memory access, while all com
 putation is performed in FP32, which keeps the similar convergence propert
 y as FP32, while the computational performance is close to FP16. The devel
 oped solvers are optimized on Fugaku (A64FX), and applied to ill-condition
 ed matrices with 90 billion DOFs in JUPITER. The P-CG and MGCG solvers wit
 h the new IR preconditioner show excellent strong scaling up to 8,000 CPUs
 , where 5.7x and 3.4x speedups are respectively achieved from the conventi
 onal solvers on Oakforest-PACS (KNL).\n\nTag: Online Only, Algorithms, Ext
 reme Scale Computing\n\nRegistration Category: Workshop Reg Pass
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