Hadrien Hendrikx

Briefly I am a researcher (Chargé de Recherche) in the Thoth team at Inria Grenoble, a French public research institute. From October 2021 to December 2022, I was a post-doc in the MLO team from EPFL, working with Martin Jaggi. Before that (2018-2021), I was a Ph.D. student in the SIERRA and DYOGENE (now ARGO) teams from Inria Paris, which are also part of the Computer Science Department of Ecole Normale Supérieure. I was also part of the MSR-INRIA joint centre. I worked under the supervision of Francis Bach and Laurent Massoulié on decentralized optimization. Prior to that, I graduated from Ecole Polytechnique in 2016 and got a master degree from EPFL in Computer Science (Master en Informatique) in 2018. During my master, I had the chance to work as a Research Assistant in the DCL lab under the supervision of Rachid Guerraoui and in close collaboration with Aurélien Bellet. Contact Physical address: Inria, 655 Av. de l'Europe, 38330 Montbonnot-Saint-Martin E-mail: hadrien [dot] hendrikx [at] inria [dot] fr

Openings

All my openings for 2025 have been filled. Feel free to contact me if you're interested in ML for ecology, as I might have a few projects coming up.

Research interests

I am broadly interested in optimization for machine learning, regardless of the flavor: stochastic, accelerated, non-euclidean… My two main research directions in this area are distributed optimization (and in particular challenges tied to robustness, privacy and personalization), and mirror descent methods (and in particular how to develop a consistent stochastic theory).

I currently focus most of my energy on developing projects at the interface between machine learning and other scientific disciplines, and in particular ecology. I am for instance part of the CASCA project with the Eco&Sol lab, where we leverage modern computer vision to better understand underground fauna.

Please contact me for discussions and potential collaborations!

Teaching

• 2024 - 2025: Teacher, Numerical Optimization, M1 Applied Mathematics, Université Grenoble Alpes

• 2024 - 2025: Teacher (part-time), Generalizations Properties of Machine Learning Algorithms, M2 Mathématiques de l'aléatoire, Orsay.

• 2023 - 2024: Teacher, Numerical Optimization, M1 Applied Mathematics, Université Grenoble Alpes

• 2023 - 2024: Teacher (part-time), Generalizations Properties of Machine Learning Algorithms, M2 Mathématiques de l'aléatoire, Orsay.

• 2019 - 2020: Teaching assistant, Advanced Algorithms (L3 Informatique), University Paris Descartes

• 2018 - 2019: Teaching assistant, Advanced Algorithms (L3 Informatique), Logic (L1 Informatique) University Paris Descartes

Reviewing

• Conferences: ICML 2019 (Top 5%), NeurIPS 2019 (Top 400), ICML 2020 (Top 33%), NeurIPS 2020 (Top 10%), AISTATS 2021, ICML 2021, NeurIPS 2021, AISTATS 2022, ICML 2022 (Top 10%), NeurIPS 2022, AISTATS 2023 (Top 10%), ICML 2023, AISTATS 2023, AISTATS 2024, ICML 2024, NeurIPS 2024.

• Journals: Mathematical Programming, IEEE Transactions on Signal Processing, Automatica, SIOPT, JMLR

Supervision

Current:

• Renaud Gaucher: PhD Student, Byzantine-robust optimization. Co-supervised with Aymeric Dieuleveut

• Loukas Duqué: PhD Student, ML for wireless communications. Co-supervised with Jean-Marie Gorce and Florence Forbes

• Géraud Ilinca: PhD Student, Dimensionality reduction for large-scale physics simulation. Co-supervised with Thomas Moreau

• Morgan Scalabrino: Master Student, Invertebrates detection and classification

• Manuela Giraldo Obando: Master student, attacks in distributed learning

Former:

• Mohamed Bacar Abdoulandhum: Master Student, co-supervised with Léa Lugassy (PADV)

• Daniel Morales Broton: Master Student.

• Abdellah El Mrini: Master Student

• Rustem Islamov: Master Student

• Mathieu Even: PhD student at INRIA Paris with Laurent Massoulié

Publications and preprints

• R. Gaucher, A. Dieuleveut, H. Hendrikx, Byzantine-Robust Gossip: Insights from a Dual Approach.
  [arXiv:2405.03449], International Conference on Machine Learning (ICML), 2025.

• M. Even, H. Hendrikx, L. Massoulié. Decentralized Optimization with Heterogeneous Delays: a Continuous-Time Approach.
  [arXiv:2106.03585], IEE Transactions on Automatic Control, 2025.

• H. Hendrikx, Investigating Variance Definitions for Stochastic Mirror Descent with Relative Smoothness.
  [arXiv:2404.12213], arXiv preprint, 2024.

• D. Morales-Brotons, T. Vogels, H. Hendrikx, Exponential Moving Average of Weights in Deep Learning: Dynamics and Benefits,
  [arXiv:], Transactions on Machine Learning Research (TMLR), 2024.

• H. Hendrikx, P. Mangold, A. Bellet. The Relative Gaussian Mechanism and its Application to Private Gradient Descent.
  [arXiv:2308.15250], International Conference on Artificial Intelligence and Statistics (AISTATS), 2024.

• A. Koloskova*, H. Hendrikx*, S. Stich. Revisiting Gradient Clipping: Stochastic bias and tight convergence guarantees.
  [arXiv:2305.01588], International Conference on Machine Learning (ICML), 2023.

• T. Vogels*, H. Hendrikx*, M. Jaggi. Beyond spectral gap (extended): the role of the topology in decentralized learning.
  [arXiv:2301.02151], Journal of Machine Learning Research (JMLR), 2023.

• H. Hendrikx. A principled framework for the design and analysis of token algorithms.
  [arXiv:2205.15015, video], International Conference on Artificial Intelligence and Statistics (AISTATS), 2023.

• T. Vogels*, H. Hendrikx*, M. Jaggi. Beyond spectral gap: the role of the topology in decentralized learning.
  [arXiv:2206.03093, video], Advances in Neural Information Processing Systems (NeurIPS), 2022.

• H. Hendrikx. Accelerated Methods for Distributed Optimization.
  [HAL link], PhD Thesis, PSL Research university, 2021.

• M. Even, R. Berthier, F. Bach, N. Flammarion, P. Gaillard, H. Hendrikx, L. Massoulié, A. Taylor A Continuized View on Nesterov Acceleration for Stochastic Gradient Descent and Randomized Gossip.
  [arXiv:2106.07644, video], Advances in Neural Information Processing Systems (NeurIPS), 2021. Oral Presentation. Outstanding paper award.

• H. Hendrikx, F. Bach, L. Massoulié. An Optimal Algorithm for Decentralized Finite Sum Optimization.
  [arXiv:2005.10675], SIAM Journal on Optimization, 2021.

• R. Dragomir*, M. Even*, H. Hendrikx*. Fast Stochastic Bregman Gradient Methods: Sharp Analysis and Variance Reduction.
  [arXiv:2104.09813], International Conference on Machine Learning (ICML), 2021.

• H. Hendrikx, F. Bach, L. Massoulié. Dual-Free Stochastic Decentralized Optimization with Variance Reduction.
  [arXiv:2006.14384], Advances in Neural Information Processing Systems (NeurIPS), 2020.

• H. Hendrikx, L. Xiao, S. Bubeck, F. Bach, L. Massoulié. Statistically Preconditioned Accelerated Gradient Method for Distributed Optimization.
  [arXiv:2002.10726, video], International Conference on Machine Learning (ICML), 2020.

• A. Bellet, R. Guerraoui, H. Hendrikx. Who started this rumor? Quantifying the natural differential privacy guarantees of gossip protocols.
  [arXiv:1902.07138], International Symposium on DIStributed Computing (DISC), 2020.

• H. Hendrikx, F. Bach, L. Massoulié. An Accelerated Decentralized Stochastic Proximal Algorithm for Finite Sums.
  [arXiv:1905.11394], Advances in Neural Information Processing Systems (NeurIPS), 2019.

• H. Hendrikx, F. Bach, L. Massoulié. Accelerated Decentralized Optimization with Local Updates for Smooth and Strongly Convex Objectives.
  [arXiv:1810.02660], International Conference on Artificial Intelligence and Statistics (AISTATS), 2019.

• EME Mhamdi, R Guerraoui, H Hendrikx, A Maurer. Dynamic Safe Interruptibility for Decentralized Multi-Agent Reinforcement Learning.
  [arXiv:1704.02882], Advances in Neural Information Processing Systems (NIPS), 2017. Spotlight presentation.

• H. Hendrikx, M. Nuñez del Prado Cortez. Towards a route detection method based on detail call records.
  [IEEE Xplore 7885725], In Computational Intelligence (LA-CCI), 2016 IEEE Latin American Conference on (pp. 1-6). IEEE., 2016.

* denotes equal contribution