Bartolomeo Stellato

@bstellato
146 Followers
198 Following
33 Posts

Assistant Professor at #princeton

๐Ÿ‘จโ€๐Ÿ’ป osqp.org developer
๐Ÿ“– Interested in #realtime #decisionmaking, #optimization, #optimalcontrol #orms
๐ŸŒ From ๐Ÿ‡ฎ๐Ÿ‡น in ๐Ÿ‡บ๐Ÿ‡ฒ

Websitehttps://stella.to

๐Ÿ“ข Our paper "Verification of First-Order Methods for Parametric Quadratic Optimization" with my student Vinit Ranjan (https://vinitranjan1.github.io/) is accepted in Mathematical Programming! ๐ŸŽ‰

We present an optimization-based framework to โœ… verify finite-step convergence of first-order methods โ€” directly capturing the structures of parametric linear and quadratic problems.

Slides on these ideas (INRIA ENS) https://stellato.io/assets/downloads/presentations/2025/ens_fom.pdf
๐Ÿ”— https://doi.org/10.1007/s10107-025-02261-w
๐Ÿ’ป https://github.com/stellatogrp/sdp_algo_verify

Data Compression for Fast Online Stochastic Optimization

Irina Wang, Marta Fochesato, Bartolomeo Stellato
https://arxiv.org/abs/2504.08097 https://arxiv.org/pdf/2504.08097 https://arxiv.org/html/2504.08097

arXiv:2504.08097v1 Announce Type: new
Abstract: We propose an online data compression approach for efficiently solving distributionally robust optimization (DRO) problems with streaming data while maintaining out-of-sample performance guarantees. Our method dynamically constructs ambiguity sets using online clustering, allowing the clustered configuration to evolve over time for an accurate representation of the underlying distribution. We establish theoretical conditions for clustering algorithms to ensure robustness, and show that the performance gap between our online solution and the nominal DRO solution is controlled by the Wasserstein distance between the true and compressed distributions, which is approximated using empirical measures. We provide a regret analysis, proving that the upper bound on this performance gap converges sublinearly to a fixed clustering-dependent distance, even when nominal DRO has access, in hindsight, to the subsequent realization of the uncertainty. Numerical experiments in mixed-integer portfolio optimization demonstrate significant computational savings, with minimal loss in solution quality.

Data Compression for Fast Online Stochastic Optimization

We propose an online data compression approach for efficiently solving distributionally robust optimization (DRO) problems with streaming data while maintaining out-of-sample performance guarantees. Our method dynamically constructs ambiguity sets using online clustering, allowing the clustered configuration to evolve over time for an accurate representation of the underlying distribution. We establish theoretical conditions for clustering algorithms to ensure robustness, and show that the performance gap between our online solution and the nominal DRO solution is controlled by the Wasserstein distance between the true and compressed distributions, which is approximated using empirical measures. We provide a regret analysis, proving that the upper bound on this performance gap converges sublinearly to a fixed clustering-dependent distance, even when nominal DRO has access, in hindsight, to the subsequent realization of the uncertainty. Numerical experiments in mixed-integer portfolio optimization demonstrate significant computational savings, with minimal loss in solution quality.

arXiv.org

๐Ÿš€ Gave a talk at the EURO OSS Seminar Series on "Data-Driven Algorithm Design and Verification for Parametric Convex Optimization"!

๐ŸŽฅ Recording: https://euroorml.euro-online.org/

Big thanks to Dolores Romero Morales for the invitation! ๐Ÿ™Œ #MachineLearning #Optimization #ORMS

EURO Online Seminar Series on Operational Research and Machine Learning

A good motivational reading assignment for an OR or combinatorial optimization class: https://www.wsj.com/articles/southwest-airlines-melting-down-flights-cancelled-11672257523 It pins a lot of the Southwest meltdown on a failure of its software to intelligently solve routing problems.
How Southwest Airlines Melted Down

Airline executives and labor leaders point to inadequate technology systems as one reason why a brutal winter storm turned into a debacle

The Wall Street Journal

#introduction

I am a scientist at Meta AI in NYC and study machine learning and optimization, recently involving reinforcement learning, control, optimal transport, and geometry. On social media, I enjoy finding and boosting interesting content from the original authors on these topics

I made this small animation with my recent project on optimal transport that connects continuous structures in the world. The source code to reproduce this and other examples is online at https://github.com/facebookresearch/w2ot

GitHub - facebookresearch/w2ot: Euclidean Wasserstein-2 optimal transportation

Euclidean Wasserstein-2 optimal transportation. Contribute to facebookresearch/w2ot development by creating an account on GitHub.

GitHub
Happy 75th birthday to the transistor, the invention that shaped the modern world!
https://spectrum.ieee.org/invention-of-the-transistor
The Transistor at 75

The past, present, and future of the modern worldโ€™s most important invention

IEEE Spectrum
Next week I'll be at #NeurIPS2022 presenting a couple of papers. The first one is on #autodiff through #optimization (aka #unrolling) and its bizarre convergence properties. A ๐Ÿงต on the paper (https://arxiv.org/pdf/2209.13271.pdf) (1/9)

I'm a professor & #ISYE dept chair at #uwmadison, #INFORMS President-Elect, and the author of the blog #PunkRockOR.

I'm into
- public sector operations research (#ORMS)
- data analytics and engineering for social good
- public engagement with science
- contributing to society and future generations through research and higher ed

my Mastodon #intro/#introduction

#introductions

Hi, I'm Pietro. I work in the Discrete Optimization and Operations Research Group at the Politecnico di Milano. My research interests are in nonconvex optimization (mixed integer and nonlinear), multiobjective optimization, and optimization under uncertainty.

I am the developer of Couenne, an open-source MINLP solver. I also worked in the dev. team of FICO Xpress.

Glad to switch to a social network with the same name as a heavy metal band ๐Ÿ˜›

#orms
#minlp

I don't want to just be posting about numbers like a clock, but the 2 million mark of monthly active users across the network is a pretty big deal. This is going big numbers! Shout out to all the server operators who are absorbing this wave.