Enum RrfFusion 

pub enum RrfFusion {
    Client {
        k: usize,
    },
    Moon {
        k: usize,
        weights: [f64; 2],
    },
}

RRF (Reciprocal Rank Fusion) mode for the retrieval DSL.

Phase 2’s fuse_rrf operator chooses between client-side fusion and Moon-native text().hybrid_search() based on this hint and the backend’s StorageCapabilities::native_rrf flag. Phase 1.5 (STORE-09) ships the type + the capability bit; Phase 2 wires the operator that consumes them.

Example

use lunaris_core::RrfFusion;

// Always available: the fold happens in-process, so it needs no
// backend capability at all.
let client_side = RrfFusion::Client { k: 60 };

// Only valid when capabilities().native_rrf == true (Moon backend) AND
// both branches are Vector + Keyword(BM25) on the same Moon index.
let moon_native = RrfFusion::Moon { k: 60, weights: [0.5, 0.5] };
match moon_native {
    RrfFusion::Moon { k, weights } => {
        assert_eq!(k, 60);
        assert_eq!(weights, [0.5, 0.5]);
    }
    _ => unreachable!(),
}

Variants

Client

Client-side fusion: collect both branches’ results, apply 1 / (k + rank) per branch, sum scores. Works on any StoragePort backend regardless of capabilities().native_rrf.

Fields

k: usize

Moon

Moon-native fusion: invoke FT.SEARCH ... HYBRID VECTOR ... SPARSE ... FUSION RRF WEIGHTS <bm25_w> <vec_w> in a single round trip via client.text().hybrid_search(). Only valid when capabilities().native_rrf == true AND both branches are Vector and Keyword(BM25) operators on the same Moon index. Phase 2’s fuse_rrf query planner picks this variant when both hold; anything else — a Graph branch in the tree, or legs on different indices — folds Client-side.

Fields

k: usize

RRF constant in the 1 / (k + rank) formula. Conventional value: 60.

weights: [f64; 2]

Branch weights [bm25_weight, vector_weight]. Both must be non-negative and finite (moon-client’s text().hybrid_search rejects negative or NaN/Inf weights). Conventional balanced value: [0.5, 0.5].

Trait Implementations

impl Clone for RrfFusion

fn clone(&self) -> RrfFusion

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for RrfFusion

impl Debug for RrfFusion

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl PartialEq for RrfFusion

fn eq(&self, other: &RrfFusion) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for RrfFusion