{"ID":6138386,"CreatedAt":"2026-07-09T01:07:32.349475501Z","UpdatedAt":"2026-07-11T17:47:58.155493336Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2607.07687","arxiv_id":"2607.07687","title":"Scaling WaterLily.jl with MPI and an improved geometric multigrid solver","abstract":"We present recent performance-oriented developments in WaterLily.jl, a scale-resolving incompressible flow solver written in pure Julia that runs seamlessly on CPUs and GPUs of any vendor. Supported by the newly added MPI-based parallelism, strong-scalability tests display a near-ideal linear trend, and weak-scaling efficiency is kept above 85\\% before node memory-concurrency contention dominates parallel performance. Inter-node weak scalability is sustained above 96\\% with grid size up to 1 billion cells. We further benchmark improvements to the geometric multigrid Poisson solver enabled by an adaptive under-relaxed red-black Gauss--Seidel smoother together with anisotropic coarsening operators.","short_abstract":"We present recent performance-oriented developments in WaterLily.jl, a scale-resolving incompressible flow solver written in pure Julia that runs seamlessly on CPUs and GPUs of any vendor. Supported by the newly added MPI-based parallelism, strong-scalability tests display a near-ideal linear trend, and weak-scaling ef...","url_abs":"https://arxiv.org/abs/2607.07687","url_pdf":"https://arxiv.org/pdf/2607.07687v1","authors":"[\"Bernat Font\",\"Marin Lauber\",\"Tzu-Yao Huang\",\"Gabriel D. Weymouth\"]","published":"2026-07-08T17:47:21Z","proceeding":"physics.comp-ph","tasks":"[\"physics.comp-ph\",\"cs.DC\",\"physics.flu-dyn\"]","methods":"[]","has_code":false}