What Are Sparse Embeddings: Vocab-Sized Vectors That Are 99% Zero

tomaarsen · x · 2026-09-17

In the SparseUp release thread, tomaarsen explains the basics: sparse embedding models embed text into vectors whose dimensionality often equals the vocabulary size, with 99% of positions at zero—only a few active dims.

This is an explanatory reply to Linkup's open-weight SparseUp release; details and benchmarks are in the main thread post.

Related event: Linkup Open-Sources SparseUp, Top Sub-150M Sparse Retrieval Model(6 posts)→

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