Jukka Aho
7f4c2b28ce
Design for handling both nodal and element fields in nodal assembly: Architecture: - Nodes have geometry (immutable) - Elements have connectivity + fields (immutable struct) - Nodal fields: displacement, temperature, contact pressure - Element fields: integration point data (σ, ε_plastic, α, C) Update pattern: - Create new field containers (NamedTuples) - Create new elements with updated fields - Shallow copy element vector, replace elements - All immutable (GPU-compatible, thread-safe) GPU kernel: - Loops over nodes (nodal assembly) - Accesses nodal_fields for global quantities - Accesses element.fields for integration point data - Gathers from connected elements (node_to_elements) - No atomic operations (each node owns DOFs) Material state update: - Process elements in parallel (Threads.@threads) - Extract nodal displacements from solution - Compute strains at integration points - Run material model (plasticity, damage, etc.) - Create new elements with updated state - Return new problem with updated fields Newton iteration: - Residual uses element.fields.C (current tangent) - GMRES with matrix-free matvec (nodal assembly) - Material update after each iteration - All data structures immutable throughout Benchmarks show creating new containers ~1000× faster than deepcopy
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| JuliaFEM Documentation | Three-tier documentation structure for users, contributors, and researchers | 2025-11-09 | Jukka Aho |
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Welcome! JuliaFEM documentation is organized into three manuals for three different audiences:
📘 User Manual - "Just Get It Done"
For: End users, engineers, students who want to run simulations.
Style: Simple, practical, step-by-step.
Contents:
- Quick start and installation
- Tutorials and examples
- API reference
- Troubleshooting
Philosophy: Show me how to solve my problem, skip the lectures.
👉 Start Here if you want to run simulations.
🔧 Contributor Manual - "Show Me the Code"
For: Developers, contributors, advanced users who want to extend JuliaFEM.
Style: Technical, detailed, design rationale.
Contents:
- Testing philosophy
- Code style and architecture
- Performance guidelines
- How to add elements
- CI/CD and git workflow
Philosophy: Explain HOW the code works and WHY we made these choices.
👉 Start Here if you want to contribute code.
📖 The JuliaFEM Book - "Let Me Show You How I Think"
For: Advanced researchers, theory nerds, those who want to understand deeply. And Jukka.
Style: Comprehensive, educational, opinionated, personal.
Contents:
- Mathematical foundations (Lagrange basis, contact mechanics, etc.)
- Design philosophy and technical vision
- Strategic mistakes and lessons learned (2015-2019)
- Research directions (nodal assembly, matrix-free, etc.)
- Personal reflections on the journey
Philosophy: Mix theory, software design, and personal experience. Teach FEM through implementation.
👉 Start Here if you love deep dives and want to understand the "why" behind everything.
Quick Navigation
I want to...
- Solve a heat transfer problem → User Manual
- Add a new element type → Contributor Manual
- Understand Lagrange basis functions → Book: Lagrange Basis
- Learn about testing → Contributor: Testing Philosophy
- See benchmark results → Book: Benchmarks
- Understand the design philosophy → Book: Philosophy
- Report a bug → GitHub Issues
- Ask a question → GitHub Discussions
Documentation Philosophy
Why Three Manuals?
Different readers have different needs:
- Users don't care about implementation details - they just want working code.
- Contributors need technical depth but not necessarily all the theory.
- Researchers (and Jukka) want to understand everything from first principles.
Mixing these audiences in one manual makes it too complex for users and too shallow for researchers.
Design Principles
- User Manual: Optimize for time-to-first-result
- Contributor Manual: Optimize for correctness and maintainability
- Book: Optimize for understanding and education
Cross-References
Manuals link to each other when appropriate:
- User manual links to theory when deeper understanding helps
- Contributor manual links to book for design rationale
- Book links to code examples and practical guides
Contributing to Documentation
Documentation improvements are always welcome!
- User docs: Fix errors, add examples, improve clarity
- Contributor docs: Update for new features, clarify architecture
- Book: Add theory, share insights, document research
See Contributor Manual for guidelines.
License: MIT (same as code)
Questions? Open an issue or discussion on GitHub