UMAP author recommends PyNNDescent for much faster kNN-graph construction

leland_mcinnes · x · 2026-11-12

Leland McInnes, author of UMAP, suggests that if you just want kNN-graph construction as fast as possible, or more options in the speed/quality trade space, you should look at PyNNDescent or RINND directly. He adds that PyNNDescent got much faster recently, especially for kNN-graph construction, and the new UMAP tunes its parameters to make better use of it—trading a small amount of accuracy for very significant performance gains.

PyNNDescent is a BSD-2 licensed Python library implementing Nearest Neighbor Descent for k-neighbor-graph construction and approximate nearest neighbor search, with 976 GitHub stars.

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