User profiles for Andrea Vattani

Andrea Vattani

ML Leadership at Reddit, Computer Science PhD from UC San Diego
Verified email at cs.ucsd.edu
Cited by 1964

K-means requires exponentially many iterations even in the plane

A Vattani - Proceedings of the twenty-fifth annual symposium on …, 2009 - dl.acm.org
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. …

Scalable k-means++

B Bahmani, B Moseley, A Vattani, R Kumar… - arXiv preprint arXiv …, 2012 - arxiv.org
Over half a century old and showing no signs of aging, k-means remains one of the most
popular data processing algorithms. As is well-known, a proper initialization of k-means is …

Fast greedy algorithms in mapreduce and streaming

…, B Moseley, S Vassilvitskii, A Vattani - ACM Transactions on …, 2015 - dl.acm.org
Greedy algorithms are practitioners’ best friends—they are intuitive, are simple to implement,
and often lead to very good solutions. However, implementing greedy algorithms in a …

Hartigan's method: k-means clustering without voronoi

M Telgarsky, A Vattani - Proceedings of the thirteenth …, 2010 - proceedings.mlr.press
Hartigan’s method for $ k $-means clustering is the following greedy heuristic: select a point,
and optimally reassign it. This paper develops two other formulations of the heuristic, one …

[PDF][PDF] The hardness of k-means clustering in the plane

A Vattani - Manuscript, accessible at http://cseweb. ucsd. edu …, 2009 - cseweb.ucsd.edu
We show that k-means clustering is an NP-hard optimization problem, even for instances in
the plane. Specifically, the hardness holds for k= Θ (nϵ), for any ϵ> 0, where n is the number …

Finding red balloons with split contracts: robustness to individuals' selfishness

M Cebrian, L Coviello, A Vattani… - Proceedings of the forty …, 2012 - dl.acm.org
The present work deals with the problem of information acquisition in a strategic networked
environment. To study this problem, Kleinberg and Raghavan (FOCS 2005) introduced the …

Near-optimal bounds for cross-validation via loss stability

…, S Vassilvitskii, A Vattani - International …, 2013 - proceedings.mlr.press
Multi-fold cross-validation is an established practice to estimate the error rate of a learning
algorithm. Quantifying the variance reduction gains due to cross-validation has been …

Learning mixtures of Gaussians using the k-means algorithm

K Chaudhuri, S Dasgupta, A Vattani - arXiv preprint arXiv:0912.0086, 2009 - arxiv.org
One of the most popular algorithms for clustering in Euclidean space is the $k$-means
algorithm; $k$-means is difficult to analyze mathematically, and few theoretical guarantees are …

Hiring a secretary from a poset

…, S Lattanzi, S Vassilvitskii, A Vattani - Proceedings of the 12th …, 2011 - dl.acm.org
The secretary problem lies at the core of mechanism design for online auctions. In this work
we study the generalization of the classical secretary problem in a setting where there is only …

[PDF][PDF] Preserving personalized pagerank in subgraphs

A Vattani, D Chakrabarti, M Gurevich - Proceedings of the 28th …, 2011 - Citeseer
Choosing a subgraph that can concisely represent a large real-world graph is useful in many
scenarios. The usual strategy employed is to sample nodes so that the induced subgraph …