BEGIN:VCALENDAR
VERSION:2.0
PRODID:Linklings LLC
BEGIN:VTIMEZONE
TZID:America/Chicago
X-LIC-LOCATION:America/Chicago
BEGIN:DAYLIGHT
TZOFFSETFROM:-0600
TZOFFSETTO:-0500
TZNAME:CDT
DTSTART:19700308T020000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=2SU
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0500
TZOFFSETTO:-0600
TZNAME:CST
DTSTART:19701101T020000
RRULE:FREQ=YEARLY;BYMONTH=11;BYDAY=1SU
END:STANDARD
END:VTIMEZONE
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
END:VEVENT
END:VCALENDAR