Search Results for author: Christian Sohler

Found 7 papers, 0 papers with code

Constant Approximation for Normalized Modularity and Associations Clustering

no code implementations29 Dec 2022 Jakub Łącki, Vahab Mirrokni, Christian Sohler

We study the problem of graph clustering under a broad class of objectives in which the quality of a cluster is defined based on the ratio between the number of edges in the cluster, and the total weight of vertices in the cluster.

Clustering Graph Clustering

Parallel and Efficient Hierarchical k-Median Clustering

no code implementations NeurIPS 2021 Vincent Cohen-Addad, Silvio Lattanzi, Ashkan Norouzi-Fard, Christian Sohler, Ola Svensson

In this paper we introduce a new parallel algorithm for the Euclidean hierarchical $k$-median problem that, when using machines with memory $s$ (for $s\in \Omega(\log^2 (n+\Delta+d))$), outputs a hierarchical clustering such that for every fixed value of $k$ the cost of the solution is at most an $O(\min\{d, \log n\} \log \Delta)$ factor larger in expectation than that of an optimal solution.

Clustering

Spectral Clustering Oracles in Sublinear Time

no code implementations14 Jan 2021 Grzegorz Gluch, Michael Kapralov, Silvio Lattanzi, Aida Mousavifar, Christian Sohler

The main technical contribution is a sublinear time oracle that provides dot product access to the spectral embedding of $G$ by estimating distributions of short random walks from vertices in $G$.

Data Structures and Algorithms

Fast and Accurate $k$-means++ via Rejection Sampling

no code implementations NeurIPS 2020 Vincent Cohen-Addad, Silvio Lattanzi, Ashkan Norouzi-Fard, Christian Sohler, Ola Svensson

$k$-means++ \cite{arthur2007k} is a widely used clustering algorithm that is easy to implement, has nice theoretical guarantees and strong empirical performance.

Clustering

On Coresets for Logistic Regression

no code implementations NeurIPS 2018 Alexander Munteanu, Chris Schwiegelshohn, Christian Sohler, David P. Woodruff

For data sets with bounded $\mu(X)$-complexity, we show that a novel sensitivity sampling scheme produces the first provably sublinear $(1\pm\varepsilon)$-coreset.

regression

Analysis of Agglomerative Clustering

no code implementations16 Dec 2010 Marcel R. Ackermann, Johannes Blömer, Daniel Kuntze, Christian Sohler

Assuming that the dimension $d$ is a constant, we show that for any $k$ the solution computed by this algorithm is an $O(\log k)$-approximation to the diameter $k$-clustering problem.

Clustering

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