Numerical Challenges in Lattice QCD 2022

Session

Podium Discussion

16 Aug 2022, 16:10

Landhaus Nordhelle

Conveners

Podium Discussion

• Francesco Giacomo Knechtli (Bergische Universitaet Wuppertal (DE))

39. Podium discussion contribution

Gunnar Bali (Universität Regensburg)

16/08/2022, 16:10

Some selected questions:Critical slowing down with $a\to 0$.
- Rounding issues on large volumes.
- Multiscale approaches to increase signal over noise
- Benefits of (approximate eigenvectors) and how to obtain these
- Approaches to excited state contributions: multi-state fits, GEVP, smearing.
- efficient stochastic estimation of traces, all-to-all propagators, perambulators

These are...

42. Contribution to Podium Discussion

Prof. Michele Della Morte

16/08/2022, 16:30

The following questions emerged from an e-mail discussion with Gustavo Ramirez:

1) Deflation (with approximate projection) as a multigrid method seems tricky to be ported to GPU architectures in an efficient way.

2) Can one understand why ? Is that solely due to the poor scalability of the 'little Dirac operator' ?

3) Isn't that then a general problem for multigrid methods on GPU ?...