Multithreaded event-chain Monte Carlo with local times

Botao Li (1) , Synge Todo (2, 3) , A. Maggs (4) , Werner Krauth (5)

1 LPENS - Laboratoire de physique de l'ENS - ENS Paris
2 Graduate School of Science [Tokyo]
3 ISSP - Institute for Solid State Physics [Tokyo]
4 Gulliver (UMR 7083)
5 Systèmes Classiques ou Quantiques en Interaction

We present a multithreaded event-chain Monte Carlo algorithm (ECMC) for hard spheres. Threads synchronize at infrequent breakpoints and otherwise scan for local horizon violations. Using a mapping onto absorbing Markov chains, we rigorously prove the correctness of a sequential-consistency implementation for small test suites. On x86 and ARM processors, a C++ (OpenMP) implementation that uses compare-and-swap primitives for data access achieves considerable speed-up with respect to single-threaded code. The generalized birthday problem suggests that for the number of threads scaling as the square root of the number of spheres, the horizon-violation probability remains small for a fixed simulation time. We provide C++ and Python open-source code that reproduces all our results.

Domaines: Informatique [cs]

Botao Li, Synge Todo, A. Maggs, Werner Krauth. Multithreaded event-chain Monte Carlo with local times. Computer Physics Communications, 2021, 261, pp.107702. ⟨10.1016/j.cpc.2020.107702⟩. ⟨hal-03008349⟩