Adaptive Aggregation-Based Domain Decomposition Multigrid for the Lattice Wilson--Dirac Operator

Frommer, Andreas; Kahl, Karsten; Krieg, Stefan; Leder, Björn; Rottmann, Matthias

doi:10.1137/130919507

Cited by 156 publications

(204 citation statements)

References 41 publications

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“…[38] (see also Refs. [39,40] The distance | 0 | used to determine the improvement coefficients can in principle be chosen at will as long as | 0 | = | 0 | is kept (approximately) constant, to achieve the complete removal of order terms from continuum limit extrapolations of physical observables. We restricted ourselves to points where lattice artefacts on the coefficients are small -at least at tree-level.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Non-perturbative determination of improvement coefficients using coordinate space correlators in Nf=2+1 lattice QCD

Korcyl¹,

Bali²

2016

Proceedings of 34th Annual International Symposium on Lattice Field Theory — PoS(LATTICE2016)

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We determine quark mass dependent order improvement terms of the form for nonsinglet scalar, pseudoscalar, vector and axialvector currents using correlators in coordinate space on a set of CLS ensembles. These have been generated employing non-perturbatively improved Wilson Fermions and the tree-level Lüscher-Weisz gauge action at = 3.4, 3.46, 3.55 and 3.7, corresponding to lattice spacings ranging from ≈ 0.085 fm down to 0.05 fm. In the = 2 + 1 flavour theory two types of improvement coefficients exist:, proportional to non-singlet quark mass combinations, and¯(or˜), proportional to the trace of the quark mass matrix. Combining our non-perturbative determinations with perturbative results, we quote Padé approximants parameterizing the improvement coefficients within the above window of lattice spacings. We also give preliminary results for˜at = 3.4.

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Section: Acknowledgmentsmentioning

confidence: 99%

Non-perturbative determination of improvement coefficients using coordinate space correlators in Nf=2+1 lattice QCD

Korcyl¹,

Bali²

2016

Proceedings of 34th Annual International Symposium on Lattice Field Theory — PoS(LATTICE2016)

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“…[2] as a solver for the clover-improved Wilson Dirac operator D. In the DD-αAMG method a flexible iterative Krylov solver is preconditioned at every iteration step by a multigrid approach given by the error propagation…”

Section: Dd-αamg Methodsmentioning

confidence: 99%

Multigrid accelerated simulations for Twisted Mass fermions

2018

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Abstract. Simulations at physical quark masses are affected by the critical slowing down of the solvers. Multigrid preconditioning has proved to deal effectively with this problem. Multigrid accelerated simulations at the physical value of the pion mass are being performed to generate N f = 2 and N f = 2 + 1 + 1 gauge ensembles using twisted mass fermions. The adaptive aggregation-based domain decomposition multigrid solver, referred to as DD-αAMG method, is employed for these simulations. Our simulation strategy consists of an hybrid approach of different solvers, involving the Conjugate Gradient (CG), multi-mass-shift CG and DD-αAMG solvers. We present an analysis of the multigrid performance during the simulations discussing the stability of the method. This significant speeds up the Hybrid Monte Carlo simulation by more than a factor 4 at physical pion mass compared to the usage of the CG solver.

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“…This contains several algorithmic improvements, e.g., the Hasenbusch trick, higher order integrators, a multi-level integration scheme, a deflated solver [18,6] and twisted mass reweighting: in the light fermion part of the action a twisted mass term is introduced in order to push eigenvalues of the Dirac operator away from zero and, hence, increase the stability of the HMC simulation. This is then corrected for by reweighting the observables accordingly.…”

Section: Simulation Detailsmentioning

confidence: 99%

“…For the computation of the correlators a custom version of the CHROMA software package [4] including the LIBHADRONANALYSIS library has been developed where also the multigrid solver implementation of Refs. [5,6] is used.…”

Section: Measurement Detailsmentioning

confidence: 99%

Towards the continuum limit with improved Wilson fermions employing open boundary conditions

Bali¹,

Göckeler²,

Hutzler³

et al. 2017

Proceedings of 34th Annual International Symposium on Lattice Field Theory — PoS(LATTICE2016)

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We present selected results obtained by RQCD from simulations of N f = 2 + 1 flavours of nonperturbatively O(a) improved Wilson fermions, employing open boundary conditions in time. The ensembles were created within the CLS (Coordinated Lattice Simulations) effort at five different values of the lattice spacing, ranging from 0.085 fm down to below 0.04 fm. Many quark mass combinations were realized, in particular along lines where the sum of the bare quark masses was kept fixed as well as trajectories of an approximately physical renormalized strange quark mass. Several key observables, including meson and baryon masses and the axial charge of the nucleon have been computed, and preliminary results are presented here. In some cases an accurate and controlled extrapolation to the continuum limit has become possible.

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Adaptive Aggregation-Based Domain Decomposition Multigrid for the Lattice Wilson--Dirac Operator

Cited by 156 publications

References 41 publications

Non-perturbative determination of improvement coefficients using coordinate space correlators in Nf=2+1 lattice QCD

Non-perturbative determination of improvement coefficients using coordinate space correlators in Nf=2+1 lattice QCD

Multigrid accelerated simulations for Twisted Mass fermions

Towards the continuum limit with improved Wilson fermions employing open boundary conditions

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