Deterministic CPU multithreading: supernodal Cholesky, parallel elements, LBM blocks (#50)

* parallel: deterministic thread pool helpers for the solvers (fixed partitions, ordered results) Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * solver: supernodal left-looking Cholesky, multithreaded with a fixed operation order Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * solver: parallel element matrices, stresses, Lanczos block solves and products (sums in the sequential order) Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * explicit: element updates in parallel, nodal forces added in element order (bit-identical to the sequential loop) Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * lbm: collision and streaming by fixed cell blocks in parallel, wall forces in link order (bit-identical) Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * engine: threads setting for the solve commands (session default from MODELCRAFT_THREADS or the cores); bit-identity test on 1, 2 and 7 threads Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm * docs: rayon threads in ADR 0001, the parallel crate, supernodal Cholesky Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm --------- Co-authored-by: jyviko <[email protected]> Co-authored-by: Claude Opus 5.5 <[email protected]>
2026-10-13 22:26:44 -04:00
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@@ -84,7 +84,8 @@ People trust ModelCraft with their models; a crash loses their work. **This outr
  L7 depends on egui/eframe/winit/wgpu/rfd. **Only
  `crates/geometry` may use `solidcraft-*`.**
 - **Determinism.** The same input gives the same mesh, deck and CPU solver result, bit for bit, on
-  every platform: no hash-order iteration into output, no thread-count-dependent results. GPU
+  every platform: no hash-order iteration into output, no thread-count-dependent results (threads
+  go through `modelcraft-parallel`: fixed blocks, sums in a fixed order, docs/adr/0001). GPU
  solver backends (wgpu, f32) are the one exception: deterministic per device, and checked against
  the CPU reference within a stated tolerance.
 - **Robust geometry.** Meshing decisions (orientation, in-sphere, intersection) use exact or