[flohofwoe]

Usually not by 10x though, unless the original implementation involved some really bad decisions.

[wnkrshm]

The Rust code is still only brute force - using suitable persistent acceleration structures you can probably get a 10x again or maybe even 100x, in 2D a kd-tree is really fast for NNs.

So much faster that the allocations for the result will probably be the bottleneck.