BEGIN:VCALENDAR
VERSION:2.0
PRODID:Linklings LLC
BEGIN:VTIMEZONE
TZID:Europe/Stockholm
X-LIC-LOCATION:Europe/Stockholm
BEGIN:DAYLIGHT
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
DTSTART:19700308T020000
RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
TZNAME:CET
DTSTART:19701101T020000
RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTAMP:20220812T074335Z
LOCATION:Samarkand Room
DTSTART;TZID=Europe/Stockholm:20220628T153000
DTEND;TZID=Europe/Stockholm:20220628T160000
UID:submissions.pasc-conference.org_PASC22_sess178_pap118@linklings.com
SUMMARY:On the Construction of AMG Prolongation through Energy Minimizatio
 n
DESCRIPTION:Paper\n\nOn the Construction of AMG Prolongation through Energ
 y Minimization\n\nIsotton, Franceschini, Janna\n\nAlgebraic Multigrid (AMG
 ) is a very popular iterative method used in several applications. This wi
 de spread is due to its effectiveness in solving linear systems arising fr
 om PDEs discretization. The key feature of AMG is its optimality, i.e., th
 e ability to guarantee a con- vergence rate independent of the mesh size f
 or different problems. This is obtained through a good interplay between t
 he smoother and the interpolation. Unfortunately, for difficult problems, 
 such as those arising from structural mechanics or diffusion problems with
  large jumps in the coefficients, standard smoothers and inter- polation t
 echniques are not enough to ensure a fast convergence. In these cases, an 
 improved prolongation operator is required to enhance the AMG effectivenes
 s. In this talk, we present an updated prolongation according to an energy
  minimization criterion, and show how this minimization can be seen as a c
 onstrained mini- mization problem. In details, we have that the constraint
  is twofold: the prolongation must be sparse, and its range must represent
  the operator near-kernel. To solve this problem, we propose two strategie
 s: a restricted Krylov subspace iterative procedure and the null-space met
 hod. Both approaches can be preconditioned to speed up the setup time. Fin
 ally, thanks to some numerical experiments, we demonstrate how the converg
 ence rate can be significantly increased at a reasonable setup cost.\n\nDo
 main: Computer Science and Applied Mathematics
END:VEVENT
END:VCALENDAR