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arXiv · 2602.09936

The Catastrophic Failure of The k-Means Algorithm in High Dimensions, and How Hartigan's Algorithm Avoids It

Roy R. Lederman·David Silva-Sánchez·Ziling Chen·Gilles Mordant·Amnon Balanov·Tamir Bendory
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Abstract

Lloyd's k-means algorithm is one of the most widely used clustering methods. We prove that in high-dimensional, high-noise settings, the algorithm exhibits catastrophic failure: with high probability, essentially every partition of the data is a fixed point. Consequently, Lloyd's algorithm simply returns its initial partition - even when the underlying clusters are trivially recoverable by other methods. In contrast, we prove that Hartigan's k-means algorithm does not exhibit this pathology. Our results show the stark difference between these algorithms and offer a theoretical explanation for the empirical difficulties often observed with k-means in high dimensions.

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Roy R. Lederman, David Silva-Sánchez, Ziling Chen, Gilles Mordant, Amnon Balanov, Tamir Bendory. 2026-02-10. The Catastrophic Failure of The k-Means Algorithm in High Dimensions, and How Hartigan's Algorithm Avoids It. https://arxiv.org/abs/2602.09936

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