Comparing the relative efficiency of different parallelisation strategies for Wang-Landau sampling: Case study of high-entropy alloys
Date:
Contributed talk at the 36th International Union of Pure and Applied Physics (IUPAP) Conference on Computational Physics (CCP), organised by Oak Ridge National Laboratory.
Abstract
Flat histogram methods such as Wang-Landau sampling [1] provide an efficient route for high-throughput calculation of phase diagrams in atomistic and lattice-model systems. Numerous parallelisation schemes have been proposed to improve sampling performance across distributed architectures [2-4]. In this study, these schemes are systematically benchmarked - both in isolation and in combination - to establish best practice for scalable flat-histogram simulations [5]. The schemes examined include energy-domain decomposition with both static sub-domains and a dynamic sub-domain sizing approach which we propose. We also assess the benefit of replica exchange and multiple random walkers per sub-domain to determine which factors most strongly influence parallel efficiency and load balance. The influence of sub-domain overlap is likewise discussed. As an illustrative test case, we implement [6] and apply [7] these strategies to a lattice-based model describing the internal energies of the AlTiCrMo refractory high-entropy superalloy, which is known to crystallographically order into a B2 (CsCl) structure with decreasing temperature. Our results demonstrate the superlinear speedup available from energy domain decomposition, and that implementation of non-uniform energy windows has a greater benefit than adding additional random walkers per window.
References
[1] F. Wang, D. P. Landau, Phys. Rev. Lett. 86, 2050 (2001).
[2] T. Vogel et al., Phys. Rev. Lett. 110, 210603 (2013).
[3] J. Zierenberg et al., Comput. Phys. Commun. 184, 1155-1162 (2013).
[4] J. Gross et al., Comput. Phys. Commun. 229, 57-67 (2018).
[5] H. J. Naguszewski et al. arXiv:2510.11562.
[6] H. J. Naguszewski et al., arXiv:2505.05393.
[7] C. D. Woodgate, H. J. Naguszewski et al., J. Phys.: Mater. 8, 045002 (2025).