AR-018 was marked Done while the promotion path still ran on the
constants it was meant to replace. track_gallery.hpp rejected a track
when buffer_spread (1 minus the minimum pairwise cosine) exceeded
expand_track_spread_max, and skipped a view when its raw gal_sim cleared
expand_novelty_sim. Both were bare cosines with no recorded EXCEPTION,
so both were defects under the AR-024 invariant rather than tagging gaps.
The calibrated band was real but unreachable. expand_band_lo/hi were
declared in Config and read nowhere, and set_band() had no callers, so
the gate always ran at the hardcoded 0.90/0.95 while --expand-novelty-sim
and --expand-spread-max stayed live flags.
The spread gate becomes store_coherence: the band's lower bound asked of
every pair in the store, in probability space, rather than a second
constant. admit() compares a newcomer only against its nearest existing
member, so a gradually drifting track chains A to B to C with every step
inside the band while A and C are strangers — the shape a track-ID
collision takes over a slow pan. The bound is re-asked pairwise before
anything reaches an actor's annex.
The novelty gate is deleted rather than converted. SPEC section AR-018
contrasts the band with expand_novelty_sim as the thing it replaces, and
AR-019 requires only that the band is satisfied. Novelty-seeking now
lives entirely in the eviction ordering, which ranks by similarity to the
actor's references instead of cutting at a constant, so there is nothing
left to tune but the two bounds.
BufEntry stored a raw cosine and the eviction loop compared two of them.
The map is monotonic so the ranking was never wrong, but it left a bare
cosine as a decision variable; it now stores the calibrated probability.
The [AR-018] Catch2 tag previously sat on the spread gate, reporting the
replaced mechanism as verification of its replacement. It now sits on the
band: both bounds asserted exactly, since they are inclusive and an
off-by-one there is invisible anywhere else; refusal counted on each
side; and the config bounds driven away from the shipped defaults so a
hardcoded fallback fails. The case that carries the invariant is "band
thresholds probability, not cosine" — under a calibration shifted by
0.10, cosine 0.84 is admitted and cosine 0.92 refused, the opposite of
their raw verdicts. A raw-cosine gate passes an identity-calibrated test
by accident and cannot pass that one. 15 cases, 38 assertions, passing.
scene_preview.cpp takes the flag rename because it would otherwise
reference deleted Config fields. It still does not compile, for reasons
predating this change: it also reads track_max_embed_dist and
track_max_frames_missing, retired by the earlier AR-024 tracker work, and
constructs FaceTrackerFunc with one argument where the registry and
calibration are now required.
Two notes for anyone reading the chain. The main.cpp flag rename and the
AR-018/AR-024 register rows landed in 35e7033, whose trailer names AR-004
only, so git log --grep=AR-018 will not surface them. And
docs/traceability.md is left uncommitted on purpose: regenerating it now
would bake in VR-013 rows for two experiment scripts that are not yet
committed.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
TRACES: AR-018, AR-024 | SR-005
A gallery is only valid for the embedder that produced its vectors. Cosine
similarities across models are meaningless but *look* plausible, so the mistake
is silent and every measurement taken afterwards is suspect. Stamp the embedder
identity into the gallery at build; verify it at every load.
The stamp is the model file's basename plus the SHA-256 of its bytes (plus
embed_dim). The hash decides, the name explains. A name alone is a promise
rather than a fact — models get re-exported and overwritten in place under an
unchanged filename, which is exactly the case where the weights differ and
nothing else does. A hash alone is correct but unactionable in an error message.
SHA-256 is derived from the artefact, needs no registry kept current, and costs
~0.1s for a 250MB ONNX, memoised per process.
Mismatch is a hard error in every mode, with no bypass, naming both sides.
Unstamped legacy galleries warn loudly and proceed: unknown is not known-bad,
and hard-failing every pre-existing gallery would turn the check into something
people disable rather than trust. --require-gallery-stamp (or
SAE_REQUIRE_GALLERY_STAMP=1, which propagates to subprocesses) promotes that to
a hard error — the mode measurement work should run in. scripts/stamp_gallery.py
re-binds an existing gallery with no re-embedding, so "warn" is a cheap state to
leave rather than a permanent one.
Embedding dumps carry the same stamp: a replay has no live embedder, so the dump
is the embedder as far as the gallery is concerned. Derived galleries inherit
their source's stamp; --merge and the JSON gallery merge check before writing,
since one file holding two embedding spaces cannot be untangled afterwards.
Verified in: scene_analyze, scene_preview, the sae_kpn matcher binding,
replay.py, optimize.py (once per film at startup, before the first evaluation),
movienet_eval.py and both merge paths.
Stamp logic lives in src/gallery/embedder_stamp.{hpp,cpp} and its Python twin
scripts/sae_stamp.py, kept dependency-light so replay subprocesses do not pay
sae_gallery's requests/Pillow import to ask whether two models match.
Tests: 12 new cases in test_gallery_store.cpp covering the comparison logic,
both round trips, and the SHA-256 vectors that guarantee the C++ and hashlib
stamps agree. No ONNX or GPU required.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Gallery format switches from JSON to HDF5 exclusively (JSON read-only kept for
back-compat): save_gallery always writes HDF5, and the fitted Platt-sigmoid
calibration (a, b, valid, hash) is now embedded directly in the gallery file
instead of a sidecar .calib_cache.json — identity_matcher reads it from the
loaded gallery and writes back only when the embeddings actually changed
(hash mismatch), skipping the O(n^2) refit otherwise.
Also includes: TensorRT inference backend support (ort_backend.cpp,
trt_backend.cpp), gemm_backend improvements, TransNetV2-based scene-boundary
detection wired through frame_source/face_tracker/main, and CMake build
target updates for the new sources.
Bumps the KPN submodule to feature/persistent-pipeline-reuse (push_blocking
backpressure, node_ptr/node_stats introspection, ObjectVariantNodeWrapper for
stateful functors) — needed by the optimizer's sae_kpn Python bindings.
Register a KPN event handler in both scene_analyze and scene_preview:
- Overflow events accumulate per-node dropped-frame counts, printed on exit.
- A Closed event from any node other than result_sink at EOF means a stage
died; trip an atomic so the main loop bails out instead of hanging on
'done' forever, and exit non-zero.
Bumps external/KPN to the commit that exposes set_event_handler / NodeEvent.
dtourolleandClaude Opus 5