PCMS: Parallel Coupler For Multimodel Simulations

TL;DR

This paper introduces PCMS, a GPU-accelerated framework for coupling multiple simulation codes on supercomputers, enabling efficient multimodel simulations with demonstrated scalability and flexibility.

Contribution

The paper presents PCMS, a novel GPU-accelerated coupling framework with distributed control and field mapping for high-dimensional multimodel simulations.

Findings

Successfully coupled gyrokinetic and transport codes.

Achieved 85% weak scaling efficiency on 2,080 GPUs.

Demonstrated flexibility with physics constraints and high-dimensional mapping.

Abstract

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%.