Struct HnswIndex 

pub struct HnswIndex { /* private fields */ }

HNSW approximate nearest neighbor index.

Wraps usearch::Index and provides a type-safe, ergonomic interface for dense vector operations. The index is not thread-safe internally — callers must synchronize access (e.g., via parking_lot::RwLock).

Implementations

impl HnswIndex

pub fn new(dimensions: usize, capacity: usize) -> Result<HnswIndex, Error>

Create a new HNSW index.

Arguments

• dimensions — Dimensionality of vectors (e.g., 1536 for OpenAI).
• capacity — Initial capacity hint (pre-allocated slots).

pub fn with_default_dims(capacity: usize) -> Result<HnswIndex, Error>

Create with default dimensions (1536).

pub fn add(&self, key: u64, vector: &[f32]) -> Result<(), Error>

Add a vector to the index with the given key.

The key is a u64 identifier. Callers should maintain a mapping from u64 key to logical ID (e.g., via SQLite).

pub fn search(&self, query: &[f32], k: usize) -> Result<Vec<(u64, f32)>, Error>

Search for the k nearest neighbors of the query vector.

Returns a sorted list of (key, distance) pairs. Distance is cosine distance (0.0 = identical for normalized vectors).

pub fn remove(&self, key: u64) -> Result<(), Error>

Remove a vector by key.

pub fn contains(&self, key: u64) -> bool

Check if a key exists in the index.

pub fn get(&self, key: u64) -> Option<Vec<f32>>

Get the vector stored for a key.

pub fn len(&self) -> usize

Number of vectors currently in the index.

pub fn is_empty(&self) -> bool

Whether the index is empty.

pub fn dimensions(&self) -> usize

Vector dimensions.

pub fn save(&self, path: &Path) -> Result<(), Error>

Save the index to a file.

pub fn load(path: &Path) -> Result<HnswIndex, Error>

Load (restore) an index from a file.

Returns a new HnswIndex with the same dimensions as the saved index.

pub fn reserve(&self, capacity: usize) -> Result<(), Error>

Reserve additional capacity.

pub fn rename(&self, from: u64, to: u64) -> Result<(), Error>

Rename a key (reassign vector from old key to new key).

Trait Implementations

impl Debug for HnswIndex

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.