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arXiv · 2611.01207

A Batched Hartigan's $k$-Means Clustering

Edward Raff·Michael Slawinski
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Abstract

Hartigan's $k$-means algorithm has theoretical advantages over the standard Lloyd's variant, which has become synonymous with "$k$-means". Yet, Hartigan's algorithm is far slower in practice due to its inherently sequential calculations. We devise a Batched Hartigan's method that enables vectorized calculation by exploiting the triangle inequality to expose a set of parallel-safe updates and a smaller set of sequential updates. This makes Hartigan's method competitive with Lloyd's in execution speed for the first time.

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Edward Raff, Michael Slawinski. 2026-10-31. A Batched Hartigan's $k$-Means Clustering. https://arxiv.org/abs/2611.01207

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