Use low-Mach wall speed for shared-motion GPU gate

2026-10-31 14:05:43 +08:00
parent 33dcb422c6
commit d0bcefa60c
2 changed files with 9 additions and 3 deletions
@@ -40,7 +40,11 @@ link exists. Unrelated moving/static body and probe overlaps still reject.
 This is a sufficient restricted-group condition, not support for near-contact
 or independent motion. The r4, distance8.3, dy=.5 counterexample remains rejected.
 CPU tests enumerate candidate donors/write footprints over subcell phases;
-GPU tests compare fixed vs hold and member-order permutations through crossings.
+GPU tests compare fixed vs hold and member-order permutations through crossings
+at wall speed .01 over the full +/-D envelope (8000 steps). The initial .5-speed
+fixture failed with NaNs; a single-circle control also failed at step69. That
+Mach~.866 fixture was unsuitable as a low-Mach numerical gate. Its failure is
+retained; the geometric MAX_STEP proof is unchanged, not a stability guarantee.
 CUDA kernels and arithmetic are unchanged.

 ## New structural parameters (not inherited from the paper)