DRex.jl

A Julia implementation of the D-Rex model for simulating crystallographic preferred orientation (CPO) evolution in olivine and enstatite polycrystals during plastic deformation.

DRex.jl is a Julia translation of PyDRex (Bilton et al., 2025), which itself is based on the original FORTRAN D-Rex model by Kaminski & Ribe (2001, 2004). The Julia implementation is significantly faster (>3 orders of magnitude) thanks to allocation-free inner loops via StaticArrays.jl, multi-core threading, and optional GPU offloading via KernelAbstractions.jl.

Features

• Core D-Rex solver — allocation-free per-grain rotation and volume fraction derivatives
• CPO integration — ODE-based tracking along pathlines (adaptive Tsit5), with grain boundary sliding and recrystallisation
• Voigt averaging — elastic tensor averaging over polycrystal orientations
• Diagnostics — M-index, PGR symmetry, elasticity decomposition, pole figures, Bingham average
• Velocity fields — analytical 2D fields for simple shear, convection cells, and corner flow
• Multithreading — Threads.@threads parallelisation across tracers; run with julia -t auto
• GPU support — KernelAbstractions backend (Metal, CUDA, ROCm); see GPU & Multithreading
• LaMEM integration — optional extension for coupling to 3D geodynamic simulations; see LaMEM Integration

Getting Started

• Installation — how to install the package
• Quick Start — a minimal working example
• Examples — scripts reproducing the figures of Bilton et al. (2025)
• GPU & Multithreading — parallel and GPU-accelerated computation
• LaMEM Integration — coupling to LaMEM 3D geodynamic simulations
• API Reference — full function and type documentation

Citing

If you use DRex.jl, please cite the original PyDRex paper and the Zenodo archive:

• Bilton, L., Duvernay, T., Davies, D.R., Eakin, C.M., 2025. PyDRex: predicting crystallographic preferred orientation in peridotites under steady-state and time-dependent strain. Geophysical Journal International 241, 35–57. https://doi.org/10.1093/gji/ggaf026
• Kaus, B.J.P., 2025. DRex.jl: A Julia package for simulating crystallographic preferred orientation (CPO) evolution (v0.1.0). Zenodo. https://doi.org/10.5281/zenodo.19110048