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We present an adaptive multigrid solver for application to the non-Hermitian Wilson-Dirac system of QCD. The key components leading to the success of our proposed algorithm are the use of an adaptive projection onto coarse grids that…

High Energy Physics - Lattice · Physics 2010-12-02 R. Babich , J. Brannick , R. C. Brower , M. A. Clark , T. A. Manteuffel , S. F. McCormick , J. C. Osborn , C. Rebbi

We present a new multigrid solver that is suitable for the Dirac operator in the presence of disordered gauge fields. The key behind the success of the algorithm is an adaptive projection onto the coarse grids that preserves the near null…

High Energy Physics - Lattice · Physics 2008-11-26 J. Brannick , R. C. Brower , M. A. Clark , J. C. Osborn , C. Rebbi

We present a new multigrid solver that is suitable for the Dirac operator in the presence of disordered gauge fields. The key behind the success of the algorithm is an adaptive projection onto the coarse grids that preserves the near null…

High Energy Physics - Lattice · Physics 2008-11-26 J. Brannick , R. C. Brower , M. A. Clark , J. C. Osborn , C. Rebbi

We describe an adaptive multigrid algorithm for solving inverses of the domain-wall fermion operator. Our multigrid algorithm uses an adaptive projection of near-null vectors of the domain-wall operator onto coarser four-dimensional…

High Energy Physics - Lattice · Physics 2012-05-15 Saul D. Cohen , R. C. Brower , M. A. Clark , J. C. Osborn

In lattice QCD computations a substantial amount of work is spent in solving discretized versions of the Dirac equation. Conventional Krylov solvers show critical slowing down for large system sizes and physically interesting parameter…

High Energy Physics - Lattice · Physics 2014-04-29 Andreas Frommer , Karsten Kahl , Stefan Krieg , Björn Leder , Matthias Rottmann

Adaptive multi-grid methods have proven very successful in dealing with critical slow down for the Wilson-Dirac solver in lattice gauge theory. Multi-grid algorithms developed for Staggered fermions using the K\"ahler-Dirac…

High Energy Physics - Lattice · Physics 2023-04-28 Venkitesh Ayyar , Richard Brower , M. A. Clark , Mathias Wagner , Evan Weinberg

Critical slowing down for the Krylov Dirac solver presents a major obstacle to further advances in lattice field theory as it approaches the continuum solution. We propose a new multi-grid approach for chiral fermions, applicable to both…

High Energy Physics - Lattice · Physics 2020-12-30 Richard C. Brower , M. A. Clark , Dean Howarth , Evan S. Weinberg

We present a multigrid based eigensolver for computing low-modes of the Hermitian Wilson Dirac operator. For the non-Hermitian case multigrid methods have already replaced conventional Krylov subspace solvers in many lattice QCD…

High Energy Physics - Lattice · Physics 2015-09-24 Gunnar Bali , Sara Collins , Andreas Frommer , Karsten Kahl , Issaku Kanamori , Benjamin Müller , Matthias Rottmann , Jakob Simeth

We develop an algebraic multigrid method for solving the non-Hermitian Wilson discretization of the 2-dimensional Dirac equation. The proposed approach uses a bootstrap setup algorithm based on a multigrid eigensolver. It computes test…

Numerical Analysis · Mathematics 2013-08-29 James Brannick , Karsten Kahl

We present an adaptive multigrid Dirac solver developed for Wilson clover fermions which offers order-of-magnitude reductions in solution time compared to conventional Krylov solvers. The solver incorporates even-odd preconditioning and…

High Energy Physics - Lattice · Physics 2011-05-25 J. C. Osborn , R. Babich , J. Brannick , R. C. Brower , M. A. Clark , S. D. Cohen , C. Rebbi

We report on the first successful QCD multigrid algorithm which demonstrates constant convergence rates independent of quark mass and lattice volume for the Wilson Dirac operator. The new ingredient is the adaptive method for constructing…

High Energy Physics - Lattice · Physics 2010-04-15 Ronald Babich , James Brannick , Richard C. Brower , Michael A. Clark , Saul D. Cohen , James C. Osborn , Claudio Rebbi

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…

High Energy Physics - Lattice · Physics 2025-05-21 Travis Whyte , Andreas Stathopoulos , Eloy Romero

In lattice QCD computations a substantial amount of work is spent in solving linear systems arising in Wilson's discretization of the Dirac equations. We show first numerical results of the extension of the two-level DD-\alpha AMG method to…

High Energy Physics - Lattice · Physics 2013-07-24 A. Frommer , K. Kahl , S. Krieg , B. Leder , M. Rottmann

Practical modifications of deterministic multigrid and conventional relaxation algorithms are discussed. New parameters need not be tuned but are determined by the algorithms themselves. One modification can be thought of as ``updating on a…

High Energy Physics - Lattice · Physics 2009-10-22 Thomas Kalkreuter

This paper focuses on adaptive control of the discrete-time linear quadratic regulator (adaptive LQR). Recent literature has made significant contributions in proving non-asymptotic convergence rates, but existing approaches have a few…

Systems and Control · Electrical Eng. & Systems 2026-04-27 Peter A. Fisher , Anuradha M. Annaswamy

Time-parallel algorithms seek greater concurrency by decomposing the temporal domain of a Partial Differential Equation (PDE), providing possibilities for accelerating the computation of its solution. While parallelisation in time has…

Numerical Analysis · Mathematics 2021-04-20 Federico Danieli , Scott MacLachlan

In this manuscript, we present a collective multigrid algorithm to solve efficiently the large saddle-point systems of equations that typically arise in PDE-constrained optimization under uncertainty, and develop a novel convergence…

Optimization and Control · Mathematics 2024-05-20 Gabriele Ciaramella , Fabio Nobile , Tommaso Vanzan

We study the kinematics of multigrid Monte Carlo algorithms by means of acceptance rates for nonlocal Metropolis update proposals. An approximation formula for acceptance rates is derived. We present a comparison of different coarse-to-fine…

High Energy Physics - Lattice · Physics 2009-10-22 M. Grabenstein , K. Pinn

To numerically solve a generic elliptic equation on two-dimensional domains with rectangular Cartesian grids, we propose a cut-cell geometric multigrid method that features (1) general algorithmic steps that apply to two-dimensional…

Numerical Analysis · Mathematics 2026-01-19 Jiyu Liu , Zhixuan Li , Jiatu Yan , Zhiqi Li , Qinghai Zhang

We present a multi-level algorithm for the solution of five dimensional chiral fermion formulations, including domain wall and Mobius Fermions. The algorithm operates on the red-black preconditioned Hermitian operator, and directly…

High Energy Physics - Lattice · Physics 2014-02-12 P A Boyle
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