Function maxsim

nodedb-vector/src/multivec/scoring.rs:45–57

Compute the MaxSim score between a query multi-vector and a document multi-vector. `score(Q, D) = Σᵢ maxⱼ sim(qᵢ, dⱼ)` Returns 0.0 if either side is empty.

(query: &[Vec<f32>], doc: &[Vec<f32>], metric: DistanceMetric)

///
/// Returns 0.0 if either side is empty.
pub fn maxsim(query: &[Vec<f32>], doc: &[Vec<f32>], metric: DistanceMetric) -> f32 {
    if query.is_empty() || doc.is_empty() {
        return 0.0;
    }
    query
        .iter()
        .map(|q| {
            doc.iter()
                .map(|d| dist_to_sim(scalar_distance(q, d, metric), metric))
                .fold(f32::NEG_INFINITY, f32::max)
        })
        .sum()
}

/// Budgeted MaxSim: only uses the first `budget` query vectors (Matryoshka
/// ordering).  When `budget` equals or exceeds `query.len()` this is