A Constant Approximation Algorithm for Sequential No-Substitution
k-Median Clustering under a Random Arrival Order
- URL: http://arxiv.org/abs/2102.04050v1
- Date: Mon, 8 Feb 2021 08:25:29 GMT
- Title: A Constant Approximation Algorithm for Sequential No-Substitution
k-Median Clustering under a Random Arrival Order
- Authors: Tom Hess, Michal Moshkovitz and Sivan Sabato
- Abstract summary: We study k-median clustering under the sequential no-substitution setting.
In this setting, a data stream is sequentially observed, and some of the points are selected by the algorithm as cluster centers.
We give a new algorithm for this setting that obtains a constant approximation factor on the optimal risk under a random arrival order.
- Score: 24.304228393096395
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: We study k-median clustering under the sequential no-substitution setting. In
this setting, a data stream is sequentially observed, and some of the points
are selected by the algorithm as cluster centers. However, a point can be
selected as a center only immediately after it is observed, before observing
the next point. In addition, a selected center cannot be substituted later. We
give a new algorithm for this setting that obtains a constant approximation
factor on the optimal risk under a random arrival order. This is the first such
algorithm that holds without any assumptions on the input data and selects a
non-trivial number of centers. The number of selected centers is quasi-linear
in k. Our algorithm and analysis are based on a careful risk estimation that
avoids outliers, a new concept of a linear bin division, and repeated
calculations using an offline clustering algorithm.
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