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DTSTAMP:20260421T090513Z
LOCATION:Bldg. 6 - Room 104
DTSTART;TZID=Europe/Stockholm:20260701T153000
DTEND;TZID=Europe/Stockholm:20260701T160000
UID:submissions.pasc-conference.org_PASC26_sess163_msa199@linklings.com
SUMMARY:Does halving the precision yield twice the speed?
DESCRIPTION:Dmitry Alexeev (NVIDIA Inc.)\n\nModern GPU architectures offer
  substantially higher throughput for single-precision arithmetic compared 
 to double precision, making reduced-precision computation an attractive st
 rategy for accelerating weather and climate models. In theory, halving the
  precision could yield up to twice the performance - but in practice, the 
 answer is rarely so simple.\nThis talk examines the performance implicatio
 ns of migrating key components of operational numerical weather prediction
  (NWP) models from double to single precision on GPU-accelerated HPC syste
 ms. Drawing on experiments with established atmospheric modeling framework
 s and radiation schemes, we explore where the theoretical 2x speedup is ac
 hievable and where memory bandwidth, algorithmic structure, or data moveme
 nt bottlenecks limit the gains. We discuss the interplay between precision
 , data layout, and GPU utilization, and highlight practical considerations
  for developers working with existing Fortran codebases.\nRather than offe
 ring a universal prescription, this presentation aims to build intuition f
 or when reduced precision pays off and when it does not - providing action
 able guidance for scientific developers navigating the precision-performan
 ce tradeoff on next-generation HPC platforms.\n\nDomain: Climate, Weather,
  and Earth Sciences\n\nSession Chairs: Balthasar Reuter (ECMWF) and Claudi
 a Frauen (DKRZ)\n\n
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