Jukka Aho
81f4f85f3e
Implements working GPU-accelerated nodal assembly with MPI domain decomposition: - Matrix-free matvec operation on GPU (y = A*x without assembling A) - 2-6× speedup vs CPU multi-threading (114-302 Mnodes/s) - Scales to 343K nodes / 1M DOFs with acceptable communication overhead - CSR format for GPU-friendly node-to-elements connectivity - Global-to-local index remapping for partition consistency Key components: - benchmarks/multigpu_mpi_benchmark.jl: Full MPI+CUDA implementation (555 lines) - benchmarks/multigpu_results_2025-11-09.md: Detailed performance analysis - docs/book/gpu_benchmark_milestone.md: Comprehensive tutorial documentation Performance results (NVIDIA RTX A2000 12GB, 2 MPI ranks): - 30³ mesh: 114.84 Mnodes/s, 29% communication overhead - 50³ mesh: 130.64 Mnodes/s, 61% communication overhead - 70³ mesh: 301.83 Mnodes/s, 51% communication overhead Architecture validated: Nodal assembly + matrix-free + GPU = fast and scalable. Foundation complete for production FEM solver (needs: real stiffness, GMRES, preconditioner).
title, description, date, author, categories, keywords, type
| title | description | date | author | categories | keywords | type | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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