Preprints
https://doi.org/10.5194/egusphere-2026-5366
https://doi.org/10.5194/egusphere-2026-5366
02 Nov 2026
 | 02 Nov 2026
Status: this preprint is open for discussion and under review for Geoscientific Model Development (GMD).

A GPU-accelerated geodynamic modelling framework: JUSTRELAX.JL v0.8

Albert de Montserrat, Pascal S. Aellig, Ludovic Räss, Christian Schuler, Thibault Duretz, and Boris J. P. Kaus

Abstract. The rapid evolution of high-performance computing and the widespread adoption of graphics processing units (GPUs) require corresponding advances in solver design and strategies in computational geodynamics. Pseudo-transient, or dynamic-relaxation, approaches are particularly promising for multi-physics problems on structured staggered grids and are well suited to efficient parallel execution. Here, we introduce JUSTRELAX.JL, a geodynamic code written in the Julia programming language that runs seamlessly on GPUs, from a single device to distributed multi-device systems. JUSTRELAX.JL separates material-property calculations, particle-in-cell advection, and (distributed) parallelism into dedicated packages, facilitating the integration of new physical processes, numerical methods, and solver strategies while limiting modifications to the solver core. We demonstrate the capabilities of JUSTRELAX.JL using a suite of geodynamic applications, including plastic shear-band localization, thermal convection, subduction, and magmatic systems. We assess its parallel scalability on modern GPU-based supercomputers, showing efficient scaling to hundreds of GPUs and providing a foundation for future extensions in computational geodynamics.

Competing interests: Two of the co-authors are members of the editorial board of Geoscientific Model Development.

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Albert de Montserrat, Pascal S. Aellig, Ludovic Räss, Christian Schuler, Thibault Duretz, and Boris J. P. Kaus

Status: open (until 28 Dec 2026)

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Albert de Montserrat, Pascal S. Aellig, Ludovic Räss, Christian Schuler, Thibault Duretz, and Boris J. P. Kaus
Albert de Montserrat, Pascal S. Aellig, Ludovic Räss, Christian Schuler, Thibault Duretz, and Boris J. P. Kaus
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Latest update: 02 Nov 2026
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Short summary
We developed JustRelax.jl to make Earth models more flexible and portable as computers increasingly rely on graphics processing units. This open-source tool lets researchers test the same models on ordinary processors and supercomputers. Tests reproduced established results and represented heat-driven flows, sinking plates, magma, and rock deformation. It performed well across hundreds of graphics processing units, enabling larger and more detailed studies of Earth’s changing interior.
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