Module keyframes 

The solve pass’s keyframe index: which earlier keyframes a frame might be revisiting, by visual words.

The index keeps only word postings in memory (per layer, per word, the keyframes that saw it, one per frame in frame order), as the TypeScript KeyframeIndex it replaces did. The keyframes themselves are rows the host stores (keyframe/<id>) and reads back. A revisit search is declare-then-provide: KeyframeIndex::retrieve names up to MAX_CANDIDATES candidate keyframes, the host loads those rows, keeps the ones Retrieval::admits, and scores them with the kernels’ candidate evaluation.

Structs

KeyframeIndex

Retrieval

The outcome of KeyframeIndex::retrieve.

Constants

BUDGET_DIAGNOSTIC

The diagnostic code (severity warning) the host emits when Retrieval::budget_warning is set.

DEFAULT_MIN_GAP

Keyframes closer than this many frames to the query are odometry, not revisits, unless the query says otherwise.

MAX_CANDIDATES

Candidates handed to evaluation, by vote count.

MIN_FEATURES

A query needs at least this many features to search at all.

MIN_VOTES

Votes a candidate needs.

POSTING_SPREAD

Keyframes taken from each end of one word’s posting.

QUERY_WORDS

Words sampled from a query, spread evenly over all of its words.

RETRIEVAL_BUDGET

A posting longer than this overran the retrieval budget: BUDGET_DIAGNOSTIC is due for the layer.