Phase 5 write-up for the two SPEC §13 forks now that both are built:
- results/phase5/README.md — the full argument for each fork, with the
kernel-lane demo and learned-policy ranking tables and reproduce commands.
- results/phase5/learned-policy.txt — captured `cargo run -p policy` output
over the 34-row ledger.
- docs/src/research-forks.md — new mdBook chapter, wired into SUMMARY.md.
- docs/src/roadmap.md — Phase 5 row added; the Frontier section rewritten
from "out of scope" to "built, both routed to human review", with the
honest note that the actual GPU run needs GPU hardware absent here.
- CLAUDE.md — Phase 5 COMPLETE status paragraph.
No trust-layer or gate change; this is documentation of work already
committed (learned policy b7297ad, kernel lane 5abeb60).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
The parser/service targets only ever needed byte-identical golden replay.
The kernel lane is the case that breaks it: a matmul optimization
(transpose-B for cache locality + eight-accumulator ILP) that REORDERS the
floating-point reduction, so its low bits differ by construction —
byte-identical is the wrong gate.
Adds:
- EquivalencePolicy::compare + Divergence (diff-test): byte-identical is
exact; fp-tolerance tokenizes and compares numeric tokens within
abs + rel*|baseline|, with explicit NaN handling. Non-numeric tokens and
token-count mismatches still fail exactly.
- fp-compare bin: applies a target's equivalence.toml to two output files.
- targets/matmul/kernel.c: matmul_ref (single-accumulator oracle) vs
matmul_opt (reordered, faster), with emit/check/run/bench modes.
- targets/matmul/equivalence.toml: fp-tolerance abs 1e-4 + rel 1e-3.
- scripts/kernel-lane-demo.sh + results/phase5/kernel-lane.txt: byte-identical
FAILs, fp-tolerance is EQUIVALENT, a +0.5 perturbation is still REJECTED,
speedup 3.23× measured with the same interleaved A/B + bootstrap CI.
Ledger row phase5-matmul-opt = needs-human-review: using the FP-tolerance
tier at all is a human-review signal (SPEC §8), same posture as mimalloc.
The trust machinery is unchanged; only the timer and the gate differ, which
is exactly the shape a future GPU kernel would slot into.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EcKPWQ3MQD4NdEHwar96u2
Claude