Title
k-means Requires Exponentially Many Iterations Even in the Plane
Abstract
The k-means algorithm is a well-known method for partitioning n points that lie in the d-dimensional space into k clusters. Its main features are simplicity and speed in practice. Theoretically, however, the best known upper bound on its running time (i.e., n O(kd)) is, in general, exponential in the number of points (when kd=Ω(n/log n)). Recently Arthur and Vassilvitskii (Proceedings of the 22nd Annual Symposium on Computational Geometry, pp. 144–153, 2006) showed a super-polynomial worst-case analysis, improving the best known lower bound from Ω(n) to $2^{\varOmega (\sqrt{n})}$ with a construction in $d=\varOmega (\sqrt{n})$ dimensions. In Arthur and Vassilvitskii (Proceedings of the 22nd Annual Symposium on Computational Geometry, pp. 144–153, 2006), they also conjectured the existence of super-polynomial lower bounds for any d≥2. Our contribution is twofold: we prove this conjecture and we improve the lower bound, by presenting a simple construction in the plane that leads to the exponential lower bound 2Ω(n).
Year
DOI
Venue
2011
10.1007/s00454-011-9340-1
Clinical Orthopaedics and Related Research
Keywords
DocType
Volume
k-means algorithm,n point,n o,simple construction,computational geometry,k cluster,super-polynomial lower bound,d-dimensional space,annual symposium,k-means requires exponentially,super-polynomial worst-case analysis,lower bound,k means,upper bound,k means algorithm,local search
Journal
45
Issue
ISSN
Citations 
4
0179-5376
48
PageRank 
References 
Authors
2.56
11
1
Name
Order
Citations
PageRank
Andrea Vattani117111.45