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Retrieval & EmbeddingsMedium· Sparse Retrieval· SPLADE· Inverted Index

What does SPLADE change compared to a standard BM25 index?

A strong answer notes that the scoring form remains s(q, d) = ∑ wqj wdj and continues to use an inverted index. By using an MLM head over all 30,522 vocabulary entries, SPLADE enables the weighting of terms not explicitly present in the document, which closes the retrieval gap. The trade-off is that the number of nonzeros per document increases, which leads to longer posting lists and higher query costs.

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