Batch::iteration: 29.840 µs → 21.253 µs (1.40×)
Gaussian::mul: 1.568 ns → 218.69 ps (7.17×)
Gaussian::div: 1.572 ns → 218.64 ps (7.19×)
Gaussian arithmetic hit target (7×+ vs 1.5–2× expected). Batch::iteration
reached 1.40× vs the 3× target. Post-mortem: the bench exercises 100 tiny
2-team events and the dominant cost is still Vec allocation in within_priors,
sort_perm, and Game::likelihoods. The HashMap→Vec win shows at the History
level (forward/backward sweep) which this bench doesn't exercise.
Remediation plan documented in benches/baseline.txt: arena-ify sort_perm,
within_priors, and Game::likelihoods in T1 when Game's internals are
redesigned around the new factor graph.
38/38 tests passing. Closes T0 tier.
Anders Olsson
d3cfee53a1