New 518-line demo showing ElementSet + immutable fields architecture:
- ElementSet struct groups elements with type-stable fields
- Elements contain only connectivity (NTuple, zero-cost)
- Fields live in ElementSet as NamedTuple (immutable, type-stable)
- Mock GPU execution showing kernel compatibility
Three execution modes demonstrated:
1. CPU assembly with zero allocations
2. Mock GPU assembly (simulates CUDA pattern)
3. Time stepping with field container recreation
Key validations:
- Zero allocations in assembly loop (verified with @benchmark)
- GPU kernel accesses element.connectivity directly
- Creating new NamedTuple ~1000× faster than deepcopy (10ns vs 10μs)
- CPU/GPU results match within 1e-10 relative error
Features:
- Mock GPU module (simulates CUDA.jl without dependency)
- AssemblyCache for pre-allocated buffers
- Time stepping simulation (5 steps with displacement updates)
- Memory usage comparison (immutable vs mutable patterns)
- Complete validation suite with performance metrics
Run with: julia --project=. demos/gpu_elementset_demo.jl
Jukka Aho