This paper presents the Parallel Coupler for Multimodel Simulations (PCMS), a new GPU accelerated generalized coupling framework for coupling simulation codes on leadership class supercomputers. PCMS includes distributed control and field mapping methods for up to five dimensions. For field mapping PCMS can utilize discretization and field information to accommodate physics constraints. PCMS is demonstrated with a coupling of the gyrokinetic microturbulence code XGC with a Monte Carlo neutral transport code DEGAS2 and with a 5D distribution function coupling of an energetic particle transport code (GNET) to a gyrokinetic microturbulence code (GTC). Weak scaling is also demonstrated on up to 2,080 GPUs of Frontier with a weak scaling efficiency of 85%.
@article{arxiv.2510.18838,
title = {PCMS: Parallel Coupler For Multimodel Simulations},
author = {Jacob S. Merson and Cameron W. Smith and Mark S. Shephard and Fuad Hasan and Abhiyan Paudel and Angel Castillo-Crooke and Joyal Mathew and Mohammad Elahi},
journal= {arXiv preprint arXiv:2510.18838},
year = {2025}
}