# range_search
An [automaton](https://docs.rs/fst/latest/fst/automaton/trait.Automaton.html) to query for nearest neighbours of a byte vector (within a given distance) against an [Fst](https://docs.rs/fst/latest/fst/) that contains a population of byte vectors.
## Installation
```sh
cargo add range_search
```
## Usage
- An automaton that accepts only (144,)-u8 vectors if they are within a
squared L2-distance of 100_000.0 of a given query vector.
```rust
use range_search::RangeSearch;
use fst::{Automaton, set::{Set, SetBuilder}, IntoStreamer, Streamer};
fn main() {
// the vector we want to find neighbors for.
let query = [0x01; 144];
let aut = RangeSearch::<144>::new_l2(&query, 100_000.0).unwrap();
// Suppose you have some fst::Set of vectors.
let set = SetBuilder::memory().into_set();
// Iterate over the set of vectors close enough to the query vector.
let mut stream = set.search(aut).into_stream();
while let Some(hit) = stream.next() {
eprintln!("found a vector within the given range of the query vector {hit:#?}");
}
}
```
- An automaton that accepts only (32,)-u8 vectors (i.e. 256-dimensional binary vectors) if they are within a hamming distance of 5 of a given query vector.
```rust
use range_search::RangeSearch;
use fst::{Automaton, set::{Set, SetBuilder}, IntoStreamer, Streamer};
fn main() {
// the 256-dimensional binary vector (packed into single bit per component) that we want to find neighbors for.
let query = [0x01; 32];
let aut = RangeSearch::<32>::new_hamming(&query, 5).unwrap();
// Suppose you have some fst::Set of vectors.
let set = SetBuilder::memory().into_set();
// Iterate over the set of vectors close enough to the query vector.
let mut stream = set.search(aut).into_stream();
while let Some(hit) = stream.next() {
eprintln!("found a vector within the given range of the query vector {hit:#?}");
}
}
```