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Related papers: Speeding up the HMC algorithm: Some new results

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Clover improvement is the standard choice for lattice simulations of QCD, when the lattice artefacts coming from Wilson fermions have to be reduced. However, the clover improvement is not limited to QCD, but can be applied to a wider range…

High Energy Physics - Lattice · Physics 2013-11-26 S. Musberg , G. Münster , S. Piemonte

Polynomial approximations to the inverse of the fermion matrix are used to filter the dynamics of the upper energy scales in HMC simulations. The use of a multiple time-scale integration scheme allows the filtered pseudofermions to be…

High Energy Physics - Lattice · Physics 2015-05-28 Waseem Kamleh , Mike Peardon

We present a variant of the HMC algorithm with mass preconditioning (Hasenbusch acceleration) and multiple time scale integration. We have tested this variant for standard Wilson fermions at beta=5.6 and at pion masses ranging from 380 MeV…

High Energy Physics - Lattice · Physics 2008-11-26 C. Urbach , K. Jansen , A. Shindler , U. Wenger

We give a detailed description of the so-called Polynomial Hybrid Monte Carlo (PHMC) algorithm. The effects of the correction factor, which is introduced to render the algorithm exact, are discussed, stressing their relevance for the…

High Energy Physics - Lattice · Physics 2009-10-31 R. Frezzotti , K. Jansen

I review recent machine trends and algorithmic developments for dynamical lattice QCD simulations with the HMC algorithm for Wilson-type fermions. The topics include the trend toward multi-core processors and general purpose GPU (GPGPU)…

High Energy Physics - Lattice · Physics 2010-01-21 Ken-Ichi Ishikawa

We compare the performance of an UV-filtered Multiboson algorithm, including a global quasi-heatbath update, to the standard Hybrid Monte Carlo algorithm in full QCD with two flavours of Wilson fermions.

High Energy Physics - Lattice · Physics 2015-06-25 C. Alexandrou , Ph. de Forcrand , M. D'Elia , H. Panagopoulos

We present results from simulations using 2 flavours of O(a)-improved Wilson quarks whose masses are about 1/3 of the physical strange quark mass. We present new data on the mass of the singlet pseudoscalar meson and evidence of the onset…

High Energy Physics - Lattice · Physics 2008-11-26 CR Allton , A Hart , D Hepburn , AC Irving , B Joo , C McNeile , C Michael , SV Wright

We investigate L\"uscher's method of including dynamical Wilson fermions in a lattice simulation of QCD with two quark flavours. We measure the accuracy of the approximation by comparing it with Hybrid Monte Carlo results for gauge…

High Energy Physics - Lattice · Physics 2009-10-28 C. Alexandrou , A. Borrelli , Ph. de Forcrand , A. Galli , F. Jegerlehner

Chiral perturbation theory for eigenvalue distributions, and equivalently random matrix theory, has recently been extended to include lattice effects for Wilson fermions. We test the predictions by comparison to eigenvalue distributions of…

High Energy Physics - Lattice · Physics 2013-01-15 Poul H. Damgaard , Urs M. Heller , Kim Splittorff

Normalized hypercubic smearing improves the behavior of dynamical Wilson-clover fermions, but has the unwanted side effect that it can occasionally produce spikes in the fermion force. These spikes originate in the chain rule connecting the…

High Energy Physics - Lattice · Physics 2014-09-10 Thomas DeGrand , Yigal Shamir , Benjamin Svetitsky

We compare the performance of the PHMC algorithm with the one of the HMC algorithm in practical simulations of lattice QCD. We show that the PHMC algorithm can lead to an acceleration of numerical simulations. It is demonstrated that the…

High Energy Physics - Lattice · Physics 2009-10-31 R. Frezzotti , K. Jansen

Due to improvements in computer performance and algorithms, the rapidly increasing cost for unquenched Wilson-type fermions with lighter quarks has been ameliorated and new simulations are now possible. Here we present results using two…

High Energy Physics - Lattice · Physics 2008-11-26 M. Göckeler , R. Horsley , Y. Nakamura , D. Pleiter , P. E. L. Rakow , G. Schierholz , W. Schroers , T. Streuer , H. Stüben , J. M. Zanotti

We describe a new Hybrid Monte Carlo (HMC) algorithm for dynamical overlap fermions, which improves the rate of topological index changes by adding an additional (intensive) term to the action for the molecular dynamics part of the…

High Energy Physics - Lattice · Physics 2012-02-28 Nigel Cundy , Weonjong Lee

Tempering is used to change the quark mass while remaining in equilibrium between the trajectories of a standard hybrid Monte Carlo simulation of four flavours of staggered fermions. The algorithm is faster for small enough quark masses,…

High Energy Physics - Lattice · Physics 2007-05-23 G. Boyd

We present a detailed design of a (P)HMC simulation algorithm for N_f = 2 + 1 + 1 maximally twisted Wilson quark flavours. The algorithm retains even/odd and mass-shift preconditionings combined with multiple Molecular Dynamics time scales…

High Energy Physics - Lattice · Physics 2007-05-23 T. Chiarappa , R. Frezzotti , C. Urbach

The performance of the two-step multiboson (TSMB) algorithm is investigated in comparison with the hybrid Monte Carlo (HMC) method for compact lattice QED with standard Wilson fermions both in the Coulomb and confinement phases. The…

High Energy Physics - Lattice · Physics 2015-06-25 I. L. Bogolubsky , V. K. Mitrjushkin , I. Montvay , M. Mueller-Preussker , N. V. Zverev

We discuss the implementation of a Sheikholeslami-Wohlert term for simulations of lattice QCD with dynamical Wilson fermions as required by Symanzik's improvement program. We show that for the Hybrid Monte Carlo or Kramers equation…

High Energy Physics - Lattice · Physics 2009-10-28 Karl Jansen , Chuan Liu

A parallelizable SSOR preconditioning scheme for Krylov subspace iterative solvers in lattice QCD applications involving Wilson fermions is presented. In actual Hybrid Monte Carlo and quark propagator calculations it helps to reduce the…

High Energy Physics - Lattice · Physics 2009-10-28 S. Fischer , A. Frommer , U. Glaessner , S. Guesken , H. Hoeber , Th. Lippert , G. Ritzenhoefer , K. Schilling , G. Siegert , A. Spitz

We study efficiency of higher order integrator schemes for the hybrid Monte Carlo (HMC) algorithm. Numerical tests are performed for Quantum Chromo Dynamics (QCD) with two flavors of Wilson fermions. We compare 2nd, 4th and 6th order…

High Energy Physics - Lattice · Physics 2009-10-31 Tetsuya Takaishi

Close to the chiral limit, many calculations in numerical lattice QCD can potentially be accelerated using low-mode deflation techniques. In this paper it is shown that the recently introduced domain-decomposed deflation subspaces can be…

High Energy Physics - Lattice · Physics 2008-11-26 Martin Lüscher