JuliaFEM.jl

JuliaFEM.jl is an open-source finite element framework written in Julia. The package is still 0.x; the repository is in the middle of a deliberate architectural reset toward a stable 1.0 with a type-stable, zero-allocation, GPU-friendly assembly pipeline. Many older READMEs and tutorials still describe the previous API; when in doubt, trust the code and AGENTS.md. Contributions (bug reports, docs, tests, and features) are welcome.

Status

Current focus areas:

• Element{K, P, S, N} template with compile-time DOF layout.
• DOFHandler and DOFBasedCOOAssembler (zero-allocation hot paths).
• Microkernel-style physics in src/domains/{continuum, heat, thermo_elastic}/.
• Matrix-free apply_K!, apply_M!, Dirichlet, multipoint constraints, IC(0) / Jacobi / block-Jacobi preconditioners and a generalized eigensolver in src/assemblers/.
• A KernelAbstractions backend for the matrix-free path with a Float32 Metal smoke test in test/backend/metal/.

The legacy element-based API (Problem, update!, Analysis, …) is still present under src/legacy/ for backward compatibility but is not the recommended entry point.

Installing

using Pkg
Pkg.add("JuliaFEM")

A modern minimal example

using JuliaFEM

mesh = create_structured_box_mesh(Hex8;
    xmin = 0.0, xmax = 1.0, nx = 4,
    ymin = 0.0, ymax = 1.0, ny = 4,
    zmin = 0.0, zmax = 1.0, nz = 4,
)

S  = @DOFSet{u::DOF{Displacement{3}, Vertex}}
ET = Element{Hex8, Lagrange{1}, S}
elements, handler = create_elements!(mesh, ET)

material = LinearElastic(E = 210e9, ν = 0.3)
kernel   = ContinuumKernel(ContinuumFormulation{FullThreeD}(),
                           material, Displacement{3}())

asm   = DOFBasedCOOAssembler()
cache = create_cache(asm, elements, handler, mesh, kernel)
assemble!(cache, asm, kernel, mesh)
K, f  = extract_system(cache)

The same block is parsed from this file in test/docs/readme_example.jl, so it stays copy-pasteable as the API evolves.

For a matrix-free Krylov solve, see test/assemblers/test_dof_based_apply_K.jl and test/assemblers/test_eigensolve.jl.

Documentation

• docs/repository_layout.md: where to put new files (full text under docs/src/repository_layout.md).
• docs/: Documenter-built API reference and user-facing index. Historical Jupyter tutorials under docs/tutorials/ (2015-2016 API; reference only).
• src/<topic>/README.md: short module notes (topology, mesh, materials, ...).

Contributing

Please read docs/CONTRIBUTING.md before opening a pull request: fork and branch, keep changes review-sized, run tests, and describe what you changed.

Git commits. Keep history easy to read: small commits, usually one file; two files in one commit is fine when they are inseparable (e.g. a helper and its only caller). With .githooks/ and core.hooksPath, pre-commit caps staged paths at two and commit-msg enforces subject, summary, - bullets, and an 80-character line cap. If that workflow feels unfamiliar, open your PR with tests passing and ask for help splitting history in review.

Code expectations. Assembly hot paths must stay type-stable and allocation-free after warmup; CI and test/assemblers/test_dof_based_zero_alloc.jl guard that. The full suite:

julia --project=. -e 'using Pkg; Pkg.test()'

Use that locally before opening a PR; CI runs the same tests.

Citing

If you use JuliaFEM.jl in academic work, please cite

@article{frondelius2017juliafem,
  title   = {Julia{FEM} - open source solver for both industrial and academia usage},
  volume  = {50},
  url     = {https://rakenteidenmekaniikka.journal.fi/article/view/64224},
  doi     = {10.23998/rm.64224},
  number  = {3},
  journal = {Rakenteiden Mekaniikka},
  author  = {Frondelius, Tero and Aho, Jukka},
  year    = {2017},
  pages   = {229-233}
}