Struct DiskANN 

pub struct DiskANN<D>
where
    D: Distance<f32> + Send + Sync + Copy + Clone + 'static,
{
    pub dim: usize,
    pub num_vectors: usize,
    pub max_degree: usize,
    pub distance_name: String,
    /* private fields */
}

Main struct representing a DiskANN index (generic over distance)

Fields

dim: usize

Dimensionality of vectors in the index

num_vectors: usize

Number of vectors in the index

max_degree: usize

Maximum number of edges per node

distance_name: String

Informational: type name of the distance (from metadata)

Implementations

impl<D> DiskANN<D>

where D: Distance<f32> + Send + Sync + Copy + Clone + 'static,

pub fn build_index_default( vectors: &[Vec<f32>], dist: D, file_path: &str, ) -> Result<Self, DiskAnnError>

Build with default parameters: (M=32, L=256, alpha=1.2).

pub fn build_index_with_params( vectors: &[Vec<f32>], dist: D, file_path: &str, p: DiskAnnParams, ) -> Result<Self, DiskAnnError>

Build with a DiskAnnParams bundle.

impl<D> DiskANN<D>

where D: Distance<f32> + Default + Send + Sync + Copy + Clone + 'static,

Extra sugar when your distance type implements Default (most unit-struct metrics do).

pub fn build_index_default_metric( vectors: &[Vec<f32>], file_path: &str, ) -> Result<Self, DiskAnnError>

Build with default params and D::default() metric.

pub fn open_index_default_metric(path: &str) -> Result<Self, DiskAnnError>

Open an index using D::default() as the distance (matches what you built with).

impl<D> DiskANN<D>

where D: Distance<f32> + Send + Sync + Copy + Clone + 'static,

pub fn build_index( vectors: &[Vec<f32>], max_degree: usize, build_beam_width: usize, alpha: f32, dist: D, file_path: &str, ) -> Result<Self, DiskAnnError>

Builds a new index from provided vectors

Arguments

• vectors - The vectors to index (slice of Vec<f32>)
• max_degree - Maximum edges per node (M ~ 24-64)
• build_beam_width - Construction L (e.g., 128-400)
• alpha - Pruning parameter (1.2–2.0)
• dist - Any anndists::Distance<f32> (e.g., DistL2)
• file_path - Path of index file

pub fn open_index_with(path: &str, dist: D) -> Result<Self, DiskAnnError>

Opens an existing index file, supplying the distance strategy explicitly.

pub fn from_bytes(bytes: Vec<u8>, dist: D) -> Result<Self, DiskAnnError>

Load an index from an owned byte buffer (no file needed).

pub fn from_shared_bytes( bytes: Arc<[u8]>, dist: D, ) -> Result<Self, DiskAnnError>

Load an index from a shared byte buffer (cheap clone, multi-reader).

pub fn to_bytes(&self) -> Vec<u8>

Serialize the index to a byte vector.

pub fn search_with_dists( &self, query: &[f32], k: usize, beam_width: usize, ) -> Vec<(u32, f32)>

Searches the index for nearest neighbors using a best-first beam search. Like search but also returns the distance for each neighbor.

pub fn search(&self, query: &[f32], k: usize, beam_width: usize) -> Vec<u32>

search but only return neighbor ids

pub fn get_vector(&self, idx: usize) -> Vec<f32>

Gets a vector from the index (useful for tests)