Search Results for author: Nikos Parotsidis

Found 8 papers, 1 papers with code

Multi-Swap $k$-Means++

no code implementations28 Sep 2023 Lorenzo Beretta, Vincent Cohen-Addad, Silvio Lattanzi, Nikos Parotsidis

The $k$-means++ algorithm of Arthur and Vassilvitskii (SODA 2007) is often the practitioners' choice algorithm for optimizing the popular $k$-means clustering objective and is known to give an $O(\log k)$-approximation in expectation.

Clustering

A Metaheuristic Algorithm for Large Maximum Weight Independent Set Problems

no code implementations28 Mar 2022 Yuanyuan Dong, Andrew V. Goldberg, Alexander Noe, Nikos Parotsidis, Mauricio G. C. Resende, Quico Spaen

To solve instances of this size, we develop a new local search algorithm, which is a metaheuristic in the greedy randomized adaptive search (GRASP) framework.

Near-Optimal Correlation Clustering with Privacy

no code implementations2 Mar 2022 Vincent Cohen-Addad, Chenglin Fan, Silvio Lattanzi, Slobodan Mitrović, Ashkan Norouzi-Fard, Nikos Parotsidis, Jakub Tarnawski

Correlation clustering is a central problem in unsupervised learning, with applications spanning community detection, duplicate detection, automated labelling and many more.

Clustering Community Detection

Correlation Clustering in Constant Many Parallel Rounds

no code implementations15 Jun 2021 Vincent Cohen-Addad, Silvio Lattanzi, Slobodan Mitrović, Ashkan Norouzi-Fard, Nikos Parotsidis, Jakub Tarnawski

Correlation clustering is a central topic in unsupervised learning, with many applications in ML and data mining.

Clustering

Planar Reachability Under Single Vertex or Edge Failures

no code implementations7 Jan 2021 Giuseppe F. Italiano, Adam Karczmarz, Nikos Parotsidis

In this paper we present an efficient reachability oracle under single-edge or single-vertex failures for planar directed graphs.

Data Structures and Algorithms

Fully Dynamic Consistent Facility Location

1 code implementation NeurIPS 2019 Vincent Cohen-Addad, Niklas Oskar D. Hjuler, Nikos Parotsidis, David Saulpic, Chris Schwiegelshohn

This improves over the naive algorithm which consists in recomputing a solution at each time step and that can take up to $O(n^2)$ update time, and $O(n^2)$ total recourse.

Clustering

Online Reciprocal Recommendation with Theoretical Performance Guarantees

no code implementations NeurIPS 2018 Fabio Vitale, Nikos Parotsidis, Claudio Gentile

A reciprocal recommendation problem is one where the goal of learning is not just to predict a user's preference towards a passive item (e. g., a book), but to recommend the targeted user on one side another user from the other side such that a mutual interest between the two exists.

Balancing information exposure in social networks

no code implementations NeurIPS 2017 Kiran Garimella, Aristides Gionis, Nikos Parotsidis, Nikolaj Tatti

Our goal is to find two sets of nodes to employ in the respective campaigns, so that the overall information exposure for the two campaigns is balanced.

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