Struct RaBitQRerank 

pub struct RaBitQRerank { /* private fields */ }

Object-safe RerankCodec wrapper around RaBitQCodec.

The codec starts untrained. encode and prepare_query return RerankError::NotTrained until train() has been called with a representative sample of vectors.

from_codec accepts a pre-calibrated RaBitQCodec (used when restoring from a snapshot).

Implementations

impl RaBitQRerank

pub fn new(dim: usize, rotation_seed: u64) -> Self

Construct an untrained wrapper.

encode / distance_prepared return RerankError::NotTrained until train() is called.

pub fn from_codec(codec: RaBitQCodec) -> Self

Construct from a pre-calibrated codec (used when restoring from snapshot).

Trait Implementations

impl RerankCodec for RaBitQRerank

fn encode(&self, v: &[f32]) -> Result<Vec<u8>, RerankError>

Encode a full-precision vector to RaBitQ 1-bit bytes.

The serialised form is the raw UnifiedQuantizedVector buffer (as_bytes()): 32-byte QuantHeader followed by dim.div_ceil(8) sign-packed bits.

fn prepare_query(&self, q: &[f32]) -> Result<PreparedQuery, RerankError>

Prepare the query by computing its centroid-subtracted, rotated sign pack and the exact query norm.

The prepared form is PreparedQuery::Bytes with the layout: 4 bytes query_norm (f32 LE) || sign bytes (dim.div_ceil(8)).

fn distance_prepared( &self, prepared: &PreparedQuery, encoded: &[u8], ) -> Result<f32, RerankError>

Compute asymmetric Hamming-based L2 distance from a prepared query to a RaBitQ-encoded candidate.

Inlines RaBitQCodec::exact_asymmetric_distance (without bias_correct) using UnifiedQuantizedVectorRef to avoid a redundant allocation:

approx = q_norm² + v_norm² − 2·q_norm·v_norm·(1 − 2·hamming/dim)

Expects PreparedQuery::Bytes produced by prepare_query.

fn train(&mut self, samples: &[&[f32]]) -> Result<(), RerankError>

Calibrate from a sample of vectors.

Validates that:

• samples is non-empty.
• Every sample has length self.dim.

On success, stores the calibrated codec; subsequent encode / distance_prepared calls will succeed.

fn name(&self) -> CodecName

Identity tag for mismatch detection.

fn to_bytes(&self) -> Result<Vec<u8>, RerankError>

Serialize trained state to bytes. Each codec uses its own magic header (NDSQ / NDBIN / NDPQ / NDRBQ / NDBBQ). The bytes are codec-specific; rerank_codec_from_bytes is used for restore, paired with name().