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Bibliographic Details
Main Authors: Li, Mingyi, Metel, Michael R., Takeda, Akiko
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2506.06990
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author Li, Mingyi
Metel, Michael R.
Takeda, Akiko
author_facet Li, Mingyi
Metel, Michael R.
Takeda, Akiko
contents The K-means algorithm is one of the most widely studied clustering algorithms in machine learning. While extensive research has focused on its ability to achieve a globally optimal solution, there still lacks a rigorous analysis of its local optimality guarantees. In this paper, we first present conditions under which the K-means algorithm converges to a locally optimal solution. Based on this, we propose simple modifications to the K-means algorithm which ensure local optimality in both the continuous and discrete sense, with the same computational complexity as the original K-means algorithm. As the dissimilarity measure, we consider a general Bregman divergence, which is an extension of the squared Euclidean distance often used in the K-means algorithm. Numerical experiments confirm that the K-means algorithm does not always find a locally optimal solution in practice, while our proposed methods provide improved locally optimal solutions with reduced clustering loss. Our code is available at https://github.com/lmingyi/LO-K-means.
format Preprint
id arxiv_https___arxiv_org_abs_2506_06990
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Modified K-means Algorithm with Local Optimality Guarantees
Li, Mingyi
Metel, Michael R.
Takeda, Akiko
Machine Learning
Optimization and Control
The K-means algorithm is one of the most widely studied clustering algorithms in machine learning. While extensive research has focused on its ability to achieve a globally optimal solution, there still lacks a rigorous analysis of its local optimality guarantees. In this paper, we first present conditions under which the K-means algorithm converges to a locally optimal solution. Based on this, we propose simple modifications to the K-means algorithm which ensure local optimality in both the continuous and discrete sense, with the same computational complexity as the original K-means algorithm. As the dissimilarity measure, we consider a general Bregman divergence, which is an extension of the squared Euclidean distance often used in the K-means algorithm. Numerical experiments confirm that the K-means algorithm does not always find a locally optimal solution in practice, while our proposed methods provide improved locally optimal solutions with reduced clustering loss. Our code is available at https://github.com/lmingyi/LO-K-means.
title Modified K-means Algorithm with Local Optimality Guarantees
topic Machine Learning
Optimization and Control
url https://arxiv.org/abs/2506.06990