Method prepare_query

nodedb-vector/src/rerank/codecs/bbq.rs:155–174

Prepare the query by centering it and serialising the exact FP32 centered vector alongside the query norm. The prepared form is `PreparedQuery::Bytes` with the layout: 4 bytes query_norm (f32 LE) || dim × 4 bytes centered f32 LE.

(&self, q: &[f32])

    /// The prepared form is `PreparedQuery::Bytes` with the layout:
    ///   4 bytes query_norm (f32 LE) || dim × 4 bytes centered f32 LE.
    fn prepare_query(&self, q: &[f32]) -> Result<PreparedQuery, RerankError> {
        if q.len() != self.dim {
            return Err(RerankError::BadInput(format!(
                "bbq prepare_query: query len {} != codec dim {}",
                q.len(),
                self.dim
            )));
        }
        let codec = self.codec.as_ref().ok_or_else(|| {
            RerankError::NotTrained(
                "bbq: codec must be trained before prepare_query (call train() with a sample of vectors)"
                    .to_string(),
            )
        })?;
        let query = codec.prepare_query(q);
        Ok(PreparedQuery::Bytes(encode_payload(
            query.query_norm,
            &query.centered,
        )))
    }

    /// Compute asymmetric L2 distance from a prepared query to a BBQ-encoded
    /// candidate.