ef07e6ca3e9f10f53b84a1657ae8a807aeb82673
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Commits
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a67402961d |
Let the merge engine's dot product use the machine's kernel too
Engine::cross is the one place a dot product is computed during agglomeration — when two groups become adjacent through a third and their sub-threshold pairs, never summed because they were never interesting, have to be accounted for. It was calling the portable loop while the scan beside it had AVX2 or NEON, which on the reference library was 1,753,514 dot products taking 0.54s. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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b4d39ba33a |
File each pair under its component once, not once per component
Seeding the merge heaps was 3.06s of a 5.93s regroup on the reference 18,143-face library — more than half the pass, spent before a single merge was considered. Every component scanned the whole pair list looking for the pairs that were its own: 475 components against 804,499 pairs, 382 million set lookups to place 804,499 of them. A pair can only ever join two faces of one component, since that is what a component is, so the union-find that finds the components can file the pairs at the same time and hand each agglomeration the list it needs. The membership set inside agglomerate goes with it — it existed only to run that filter — and the heap can be sized up front now that the pair count is known. Ordering is preserved deliberately: pairs are filed in the order they arrive, which is the global (i, j) order, so the seeded heap breaks its ties exactly as before and the merge order is unchanged. Same 2,518 groups holding the same 16,246 faces on the reference library, at 3.5s rather than 5.9s. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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e596eb0657 |
Give the similarity scan the machine's SIMD, and its cache
The scan is O(n²) dot products and nothing else, so its speed is the face subsystem's speed — and it was running at 0.7 flops per cycle. Two separate faults, both measured over the reference 18,143-face library on twenty cores. It walked the whole embedding array once per row, ~336 GB of traffic, where a column tile that fits in L2 is read once per tile of rows: 4.64s → 2.81s. And the workspace builds for baseline x86-64 — SSE2, no FMA — into which the portable loop was not being vectorised at all: 2.81s → 0.86s, 195 GFLOP/s. So the dot product is now chosen per machine. AVX2 + FMA where is_x86_feature_detected! finds it; NEON unconditionally on aarch64, since Advanced SIMD is in that baseline and every Android device the app builds for has it — with the explicit vfmaq, because LLVM will not fuse a multiply and an add without being told to. The portable loop stays as the definition the others are tested against, and the_fastest_kernel_agrees_with_the_portable_one is the only check the NEON path gets on a machine that is not aarch64. Faces::embeddings is one flat buffer rather than a Vec per face: the pointer chase defeated both the prefetcher and the tiling, and it is also the layout a GPU pass would want. Behaviour is unchanged and that is checked rather than asserted — the same 1,531,969 pairs from all three kernels, and on the real library the same 2,518 groups holding the same 16,246 faces with the same confidence distribution. A full regroup there goes from 10.0s to 5.9s; the rest is the agglomeration, which is a sequential heap walk and is where the next look should go. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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ebb7d3cf5c |
Score a suggestion against the people the user has named
The number beside a suggestion was the mean calibrated probability between the face and the rest of its group, which measures the wrong thing twice. It punishes coverage: a person with two hundred faces over fifteen years is *meant* to have members a given photograph is orthogonal to, so a correct suggestion onto a well-photographed person scored low for being well photographed. And it never asked who else the face might be — a face matching Anna at 0.95 and nobody else, and one matching Anna at 0.95 and her sister at 0.93, came out identical, when the second is the only one worth the user's attention. dr_face::assign answers both, and multiplies them: the mean of the best ten calibrated matches into the identity (the old mean, capped, which is what stops coverage counting against it), times that identity's share of the evidence against every *named* rival. Only named people compete, and per person rather than per group. Both halves of that had to be measured on a real 18,000-face library rather than reasoned about. Normalising across every group made the number useless — median suggestion 21%, four in five under half — because clustering leaves one person spread over many groups, so a face competed against itself; and keying rivals by group left Catherine competing with Catherine, median 39%. Per named person: median 99.5%. Rivals are gathered below the merge threshold, down to even odds: a named person matching at 0.6 will never be merged into but is exactly the competition to discount for. That would be a second similarity scan, the expensive half of regrouping a library, so cluster_scored scans once at the looser floor and hands the merge engine the subset at or above the threshold — pair for pair what it would have scanned for itself, held to that by a test. Leave-one-out over that library's 2,702 confirmations across 54 named people: 99.33% of faces placed on the right person against the old mean's 99.15%, and the number shown for the right person moves from a median of 90.4% to 99.3%. It errs low — 100% correct wherever it states 80% or more — which is the safe direction, and docs/faces.md §9.1 says plainly that the low bands are not calibrated. The example that measures it comes too: this is a claim about a library's numbers, and nobody should have to take it on faith. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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7275c020d7 |
Group people at the threshold the library actually supports
0.90 left a third of the reference library ungrouped: 1,213 of 1,813 faces in a
group, and the rest sitting alone in a screen that had nothing to offer for
them.
"Is 0.90 too tight" is not answerable from the number. It is a probability, and
which cosine it lands on depends on the calibration — so the first half of this
is a way to ask the question properly. `face_index --tune` runs the real
clusterer over the real embeddings at ten thresholds and prints what each one
produces. It writes nothing; comparing thresholds by applying them would have
each one pollute the next.
On the reference library:
P cosine groups grouped largest
0.95 0.449 311 62% 51
0.90 0.403 316 67% 51
0.85 0.374 318 70% 57
0.80 0.353 328 74% 69
0.75 0.335 327 77% 69
0.70 0.319 326 79% 81
0.50 0.267 303 85% 90
The count of *groups* is the signal, not the count of grouped faces. Loosening
from 0.95 makes it climb: real people are being assembled out of fragments. It
peaks at 0.80 and then falls — and a falling group count while the grouped faces
keep rising is the shape of over-merging, separate identities being welded
together. That is the FR-CULL-10 failure, and the one the user cannot undo by
hand.
So 0.80: the loosest setting still building people rather than melting them
together. A third more of the library gets grouped than at 0.90, and the largest
group grows by eighteen faces rather than by forty.
The table is one library, and the doc comment says so — `--tune` reruns it on
any other.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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c10dca984f |
Regroup the library without stopping the window
Pressing Regroup on a real library did not come back. Clustering 1,813 faces is the textbook agglomeration — compute every pairwise cosine, then repeatedly scan all live group pairs, score each with average link, and merge the best — and the scan is inside the loop. Each merge rescans every surviving pair, and each score is recomputed from scratch over every cross pair. Some 1.6 million pair scores per merge, some 700 merges to do. Three changes, none of which alter the answer. Only above-threshold pairs can ever matter. An average that reaches the threshold must have at least one term at or above it, so two groups with no qualifying pair between them can never merge — not now, and not after any sequence of merges, since merging only adds terms. The new `neighbours` module produces exactly that sparse list: 7,875 pairs rather than 1.6 million on the reference library. It also means the n^2 matrix is never materialised, so memory goes from O(n^2) to O(edges) — 2.5 GB to a few hundred KB at 25,000 faces. Merges cannot cross components, so the connected components of that graph are independent problems: four hundred small agglomerations instead of one large one. Average link is additive — sum(A u B, C) = sum(A, C) + sum(B, C) — so a merged group's scores follow by addition. Kept as running (sum, count) per adjacent pair, a score costs one division instead of a nested loop, and a heap with lazy invalidation replaces the rescan. Measured on the reference library: 0.28s, release, for all 1,813 faces. An exact ANN index was tried and removed, and neighbours.rs records why so it is not rediscovered as a good idea. IVF with a triangle-inequality bound is exact and prunes beautifully on synthetic clusters; on real embeddings it prunes *nothing* — 946 of 946 cell pairs survive. Median pair angle is 88.5 degrees and the merge threshold is 66.2, so the bound needs cells of radius under ~10 degrees, but two photographs of the same person sit 36-60 degrees apart. No ball-based partition of a 512-d near-orthogonal space can be tight enough. So the scan stayed exhaustive and got an unrolled dot product and its blocks spread across cores instead. Correctness is held by keeping the old implementation as an oracle: three tests run both engines over the same population — plain, under co-occurrence and anchor constraints, and with a size-weighted calibration — and assert the clusters are identical. Determinism is asserted at a size where the threaded path is in play. 62 tests pass. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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b846b312b8 |
Run the formatter over the face branch before it reaches CI
🐳 Android image / Build and push (push) Successful in 2s
Build and test / android-image (push) Successful in 2s
Build and test / Desktop (Linux) (push) Successful in 1h21m32s
Build and test / Layer separation (push) Successful in 37s
Traceability / Requirement traces (push) Successful in 25s
Build and test / Android (aarch64) (push) Failing after 33m58s
The merge of the SCRFD/MobileFaceNet work brought 69 rustfmt diffs across
dr-catalog, dr-face and dr-ui with it, so `cargo fmt --all -- --check` fails
on master and the Desktop job stops at its Format step — before clippy, the
tests or the release build have run at all. That makes the whole desktop
half of CI blind: a real compile error behind this would look exactly the
same from the outside. There was nothing behind it, as it turns out — with
the formatting fixed, clippy, the test suite and the release build all pass.
Every .rs hunk is `cargo fmt --all` on the pinned 1.92.0 toolchain, not a
hand edit, but it is worth being precise about what that moved, because it
is more than whitespace. Besides reflowing signatures and call chains,
rustfmt reordered the `pub mod` and `pub use` items in dr-face/src/lib.rs so
the `#[cfg(feature = "inference")]` entries sort in place, added the trailing
semicolon inside `let ... else { return }` bodies in identity_ui.rs, wrapped
a bare closure body in braces in cluster.rs, adjusted trailing commas, and
dropped a stray blank line at the end of identity_ui.rs. All of it is
semantically inert; none of it changes behaviour.
docs/traceability.md rides along because it has to. The matrix records each
TRACES tag by line number, and reflowing develop.rs, lib.rs, faces.rs,
identity.rs and identity_ui.rs moved them — FR-CAT-8, FR-CAT-9, FR-CULL-10,
FR-DEV-3, FR-DEV-3a and FR-DEV-3c all shift by a line or two. The matrix was
verified up to date on
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00e78dc2ac |
Cluster faces into people, and calibrate what a similarity means
FR-CULL-9 forbids thresholding a bare cosine anywhere in the subsystem, so calibrate fits P(same person) per library and reports whether the fit is trustworthy. Two details carry most of the weight. The fit runs against a 200-bin histogram rather than a pair list: a 25,000-face library has ~3e8 pairs and no gradient descent is running over that. And a fresh library has no valid calibration, because the positives have to come from user confirmations or burst siblings -- bootstrapping them from high cosine would fit the calibration to the belief it was supposed to test. Clustering defends against the over-merging FR-CULL-10 warns about with constraints rather than a better threshold: two faces in one photograph never merge, and two groups confirmed as different people never merge. Average link rather than single link, so one strong edge cannot weld two families together. Calibration is defined once, in dr-face, and dr-catalog re-exports it. Two implementations of one probability model is exactly how a number comes to mean the wrong thing. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |