dtourolleandClaude Opus 5
c10dca984f
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>
DarkRoom
A cross-platform, non-destructive RAW photo editor for Linux and Android.
Status: early. v0.1 is a remote library viewer — see docs/milestone-v0.1.md.
Documentation
| Document | Contents |
|---|---|
| requirements.md | What the software must do — 122 numbered requirements |
| architecture.md | How it is built — crates, GPU pipeline, data model, sync |
| milestone-v0.1.md | The first buildable milestone |
| faces.md | Face detection and identity — the models, the licence problem, and what S14 measures |
Building
Desktop:
cargo run -p darkroom-desktop
Android (containerised toolchain, see docker/android):
./docker/android/build.sh cargo ndk -t arm64-v8a build --release
Current state
Working: workspace, GPU context and compute pass, adaptive Slint shell, Android cross-compilation of the core crates.
Not yet working: the zero-copy display path. The build currently uploads frames through the CPU, which is exactly what ARCH §6.1 forbids — measured at 96% of frame time at 4K. Replacing it is spike S1, the project's highest priority.
cargo run -p dr-gpu --example bench --features readback
reproduces that measurement.
Licence
GPL-3.0-or-later.