Struct QuantizedDiskANN 

pub struct QuantizedDiskANN<D>
where
    D: Distance<f32> + Send + Sync + Copy + Clone + 'static,
{ /* private fields */ }

Quantized DiskANN index — wraps a DiskANN<D> with compressed in-memory codes.

During beam search, distance computations use the compressed codes in RAM instead of reading full f32 vectors from the backing store. After search, an optional re-ranking phase re-scores top candidates with exact vectors.

Implementations

impl<D> QuantizedDiskANN<D>

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

pub fn from_pq( base: DiskANN<D>, pq: ProductQuantizer, config: QuantizedConfig, ) -> Self

Create from an existing index and a pre-trained ProductQuantizer.

Encodes all vectors from base into the in-memory codes buffer.

pub fn from_f16(base: DiskANN<D>, config: QuantizedConfig) -> Self

Create from an existing index using F16 quantization.

pub fn from_int8( base: DiskANN<D>, int8q: Int8Quantizer, config: QuantizedConfig, ) -> Self

Create from an existing index and a pre-trained Int8Quantizer.

pub fn num_vectors(&self) -> usize

Number of vectors in the index.

pub fn dim(&self) -> usize

Vector dimensionality.

pub fn base(&self) -> &DiskANN<D>

Reference to the underlying base index.

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

Get a full-precision vector from the base index.

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

Search with quantized beam search, returning (id, distance) pairs.

Distances in the returned results are:

• If rerank_size > 0: exact distances from the base index
• Otherwise: approximate distances from the quantizer

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

Search returning only neighbor IDs.

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

Batch search (parallel over queries).

pub fn search_filtered_with_dists( &self, query: &[f32], k: usize, beam_width: usize, labels: &[Vec<u64>], filter: &Filter, ) -> Vec<(u32, f32)>

Search with quantized beam search and a metadata filter.

Composes quantized distance computation with label-based filtering. labels must have one entry per vector in the index, with the same ordering as the base index vectors.

Distances in the returned results are:

• If rerank_size > 0: exact distances from the base index
• Otherwise: approximate distances from the quantizer

pub fn search_filtered( &self, query: &[f32], k: usize, beam_width: usize, labels: &[Vec<u64>], filter: &Filter, ) -> Vec<u32>

Search with filter, returning only neighbor IDs.

pub fn save_quantized(&self, path: &str) -> Result<(), DiskAnnError>

Save the quantizer state and codes to a sidecar file.

The base index should be saved separately via DiskANN::build_index or already persisted on disk.

Sidecar Format

[magic: u32 = 0x51414E4E]
[version: u32 = 1]
[quantizer_type: u8]        // 0=PQ, 1=F16, 2=Int8
[num_vectors: u64]
[code_size: u64]
[quantizer_data_len: u64]
[quantizer_data: bincode]
[codes: num_vectors * code_size bytes]

pub fn open( base_path: &str, quantized_path: &str, dist: D, config: QuantizedConfig, ) -> Result<Self, DiskAnnError>

Open a QuantizedDiskANN from a base index path and a sidecar path.

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

Serialize the quantizer + codes to bytes (without the base index).

pub fn from_bytes( bytes: &[u8], dist: D, config: QuantizedConfig, ) -> Result<Self, DiskAnnError>

Deserialize from bytes (base index + quantized data).

impl<D> QuantizedDiskANN<D>

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

pub fn build_pq( vectors: &[Vec<f32>], dist: D, file_path: &str, ann_params: DiskAnnParams, pq_config: PQConfig, config: QuantizedConfig, ) -> Result<Self, DiskAnnError>

Build a PQ-quantized index from scratch.

pub fn build_f16( vectors: &[Vec<f32>], dist: D, file_path: &str, ann_params: DiskAnnParams, config: QuantizedConfig, ) -> Result<Self, DiskAnnError>

Build an F16-quantized index from scratch.

pub fn build_int8( vectors: &[Vec<f32>], dist: D, file_path: &str, ann_params: DiskAnnParams, config: QuantizedConfig, ) -> Result<Self, DiskAnnError>

Build an Int8-quantized index from scratch.