A bad instance for k-means plus

作者:Brunsch Tobias; Roeglin Heiko
来源:Theoretical Computer Science, 2013, 505: 19-26.
DOI:10.1016/j.tcs.2012.02.028

摘要

k-means++ is a seeding technique for the k-means method with an expected approximation ratio of O(log k), where k denotes the number of clusters. Examples are known on which the expected approximation ratio of k-means++ is Omega(log k), showing that the upper bound is asymptotically tight. However, it remained open whether k-means++ yields a constant approximation with probability 1/poly(k) or even with constant probability. We settle this question and present instances on which k-means++ achieves an approximation ratio no better than (2/3 - epsilon) . log k with probability exponentially close to 1.

  • 出版日期2013-9-23