TY  - EJOUR
AU  - Whyte, Travis
AU  - Stathopolous, Andreas
AU  - Romero, Eloy
TI  - Accelerating multigrid with streaming chiral SVD for Wilsonfermions in lattice QCD
PB  - arXiv
M1  - FZJ-2025-05420
PY  - 2025
AB  - A modification to the setup algorithm for the multigrid preconditioner of Wilson fermions in lattice QCD is presented. A larger basis of test vectors than that used in conventional multigrid is calculated by the smoother and truncated by singular value decomposition on the chiral components of the test vectors. The truncated basis is used to form the prolongation and restriction matrices of the multigrid hierarchy. This modification of the setup method is demonstrated to increase the convergence of linear solvers on an anisotropic lattice with $m_π \approx 239$ MeV from the Hadron Spectrum Collaboration and an isotropic lattice with $m_π \approx 220$ MeV from the MILC Collaboration. The lattice volume dependence of the method is also examined. Increasing the number of test vectors improves speedup up to a point, but storing these vectors becomes impossible in limited memory resources such as GPUs. To address storage cost, we implement a \emph{streaming} singular value decomposition of the basis of test vectors on the chiral components and demonstrate a decrease in the number of fine level iterations by a factor of 1.7 for $m_q \approx m_{crit}$.
KW  - High Energy Physics - Lattice (hep-lat) (Other)
KW  - Numerical Analysis (math.NA) (Other)
KW  - FOS: Physical sciences (Other)
KW  - FOS: Mathematics (Other)
LB  - PUB:(DE-HGF)25
DO  - DOI:10.48550/ARXIV.2505.14399
UR  - https://juser.fz-juelich.de/record/1049632
ER  -