fann

Approx nearest neighbor search in Rust

AI & Machine Learning

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3Mentions

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166GitHub stars

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What it is

Approx nearest neighbor search in Rust

GitHub

Where it is used

No documented product use has been verified yet.

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This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 5:04:57 PM UTC.

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Mentions over time

HN mentions by hour3 dated mentions

Observed mentions: 2023-06-15 13:31:57 UTC to 2023-06-15 18:30:23 UTC.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

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Period	Start (UTC)	End (exclusive, UTC)	Mentions	Comments
Jun 15, 13:00	2023-06-15 13:00:00 UTC	2023-06-15 14:00:00 UTC	1	1
Jun 15, 14:00	2023-06-15 14:00:00 UTC	2023-06-15 15:00:00 UTC	1	1
Jun 15, 15:00	2023-06-15 15:00:00 UTC	2023-06-15 16:00:00 UTC	0	0
Jun 15, 16:00	2023-06-15 16:00:00 UTC	2023-06-15 17:00:00 UTC	0	0
Jun 15, 17:00	2023-06-15 17:00:00 UTC	2023-06-15 18:00:00 UTC	0	0
Jun 15, 18:00	2023-06-15 18:00:00 UTC	2023-06-15 19:00:00 UTC	1	1

What Hacker News says

3 sources

nikhilgarg28·Jun 15, 2023

We did some benchmarking and found that an index of 1M vectors using 15 trees can be built up in ~115 seconds (8 CPU, 8 GB RAM). https://github.com/fennel-ai/fann/pull/8. Given this, around a second to build an index of 10K items sounds about right.

In FANN: Vector Search in 200 Lines of Rust

huac·Jun 15, 2023

I'd be curious how this stacks up on ANN-benchmarks (https://ann-benchmarks.com/). FWIW exhaustive search is still probably good enough for most use cases. IMO the exhaustive search should use a heap https://github.com/fennel-ai/fann/blob/main/src/main.rs#L12 as you're only looking for top-k, it reduces time and memory complexity greatly. On a relatively unoptimized Golang implementation (though much beefier hardware) I get ~100ms to process 1M vectors of 300 dim. Still quite a bit slower than approximate, of course, but in absolute terms probably good enough for most use cases, especially because many use cases don't have 1M vectors.

In FANN: Vector Search in 200 Lines of Rust

un_ess·Jun 15, 2023

isn't it in https://github.com/fennel-ai/fann/blob/main/src/search.rs#L1... ?

In FANN: Vector Search in 200 Lines of Rust