Method distance_prepared

nodedb-vector/src/rerank/codecs/binary.rs:86–111

Compute Hamming distance from a prepared query to a binary-encoded candidate.

(
        &self,
        prepared: &PreparedQuery,
        encoded: &[u8],
    )

    /// Compute Hamming distance from a prepared query to a binary-encoded
    /// candidate.
    fn distance_prepared(
        &self,
        prepared: &PreparedQuery,
        encoded: &[u8],
    ) -> Result<f32, RerankError> {
        let q_bits = match prepared {
            PreparedQuery::Bytes(b) => b,
            _ => {
                return Err(RerankError::BadInput(
                    "binary distance: expected PreparedQuery::Bytes".to_string(),
                ));
            }
        };

        let packed_len = binary_packed_bits_len(self.dim);
        let uqv_ref = UnifiedQuantizedVectorRef::from_bytes(encoded, packed_len).map_err(|e| {
            RerankError::BadInput(format!(
                "binary distance: failed to parse encoded bytes: {e}"
            ))
        })?;

        let packed = uqv_ref.packed_bits();
        // Compute Hamming distance directly via the public helper.
        let dist = crate::quantize::binary::hamming_distance(q_bits, packed) as f32;
        Ok(dist)
    }

    fn name(&self) -> CodecName {
        CodecName::Binary