Struct TernaryCodec 

#[non_exhaustive]
pub struct TernaryCodec {
    pub dim: usize,
}

BitNet b1.58 ternary codec.

Stateless aside from dim. Per-vector scaling (absmean) is computed in VectorCodec::encode and stored in the header’s global_scale field.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

dim: usize

Implementations

impl TernaryCodec

pub fn new(dim: usize) -> Self

Trait Implementations

impl VectorCodec for TernaryCodec

type Quantized = TernaryQuantized

The packed quantized form. Must be convertible to a UnifiedQuantizedVector reference via AsRef.

type Query = TernaryQuery

The prepared query form (codec-specific).

fn encode(&self, v: &[f32]) -> TernaryQuantized

Encode a single FP32 vector into the codec’s packed form.

fn prepare_query(&self, q: &[f32]) -> TernaryQuery

Prepare a query for distance computations against this codec. May rotate, normalize, build a LUT, etc.

fn fast_symmetric_distance( &self, q: &Self::Quantized, v: &Self::Quantized, ) -> f32

Fast symmetric distance — bitwise / heuristic. Used during HNSW upper-layer routing. Both arguments are quantized; no scalar correction; no outlier resolution. Hot path; must be inline-friendly.

fn exact_asymmetric_distance( &self, q: &TernaryQuery, v: &Self::Quantized, ) -> f32

Exact asymmetric distance — full ADC with scalar correction and sparse outlier resolution. Used at base-layer rerank only. Slower but high-fidelity.

fn adc_lut(&self, _q: &Self::Query) -> Option<AdcLut>

Optional: precompute ADC lookup table for codecs that use one (PQ, IVF-PQ, TurboQuant). Returns None for codecs that don’t (RaBitQ, BBQ, ternary, binary).

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

Optional: fit the codec’s learned parameters on a set of training vectors.