video/detect.py runs these for every frame:
- get_cluster_candidates: used_boxes was a list with `in` membership tests
inside the nested loop (O(n) per check). It is only ever membership-tested,
so switching it to a set (O(1)) leaves output unchanged.
- get_consolidated_object_detections: area(current_box) was recomputed on
every inner-loop iteration though it is loop-invariant; hoist it to one
call per outer detection.
Both are bit-identical (verified against the previous implementations over
randomized inputs). Measured in the release image, get_cluster_candidates on
a frame of 30 detection boxes: 59.2 us -> 42.1 us (1.4x); the gain scales
with the number of boxes per frame.
Adds a partition-invariant test (every box index lands in exactly one
cluster).
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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