pub fn rrf_fuse(
semantic: &[(usize, f32)],
bm25: &[(usize, f32)],
k: f32,
) -> Vec<(usize, f32)>Expand description
Reciprocal Rank Fusion of two ranked lists.
Each entry in semantic and bm25 is (chunk_index, _score).
The fused score for a chunk is the sum of 1 / (k + rank + 1) across
every list the chunk appears in, where rank is 0-based.
Returns all chunks that appear in either list, sorted descending by fused RRF score.
k should typically be 60.0 — a conventional constant that smooths the
ranking boost for the very top results.