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Hyperparameter Optimization

Over the past 15 years, deep learning has emerged as the dominant force driving the AI revolution. Its key strength lies in automating feature engineering, enabling powerful end-to-end learning directly from raw data and reducing reliance on domain-specific expertise. Yet, truly automated learning pipelines remain out of reach: while manual feature design has diminished, it has been replaced by a multitude of design choices (such as architectures, optimizers, and initialization schemes) that must be carefully tuned to achieve strong performance. In this sense, domain experts have largely been replaced by deep learning experts. This group addresses this challenge by developing methods to automatically configure these critical choices. We design principled algorithms, create rigorous benchmarks for fair and efficient comparison, and build practical tools to make these advances accessible to practitioners. Our research is closely aligned with the DL 2.0 ERC consolidator grant and broader European open-science initiatives in the area of large language models.

Research Topics & Interests

Fundamental HPO

We explore core research topics in hyperparameter optimization, including black-box optimization with Bayesian Optimization, known for its sample efficiency and flexibility, user priors, which integrate human knowledge to guide optimization processes. Additionally, we investigate learning curve extrapolation and multi-fidelity optimization approaches to accelerate optimization and enable more efficient resource allocation.

HPO for large-scale Deep Learning

We aim to enable Hyperparameter Optimization for large-scale deep learning by dramatically reducing the number of full model trainings required for HPO. Our approach includes resource-efficient methods like forecasting performance from early training statistics (e.g., initial learning curve), inferring hyperparameter-aware scaling laws to predict large model behavior from smaller ones, and employing expert knowledge and meta-learning to improve sample efficiency.

HPO Benchmarks & Tools

We develop a range of high-quality benchmarks and open-source tools to advance hyperparameter optimization research. These tools are designed to make our research accessible and practical for non-experts. Additionally, our benchmarks provide a robust framework for comparison and evaluation across HPO studies, promoting scientific rigor and facilitating researchers’ work. Widely adopted in the HPO community, our tools and benchmarks remain a standard in the field.

Group Members

Subgroup Lead

PhD Students

Students

Anton Merlin Geburek

Nastaran Alipour Gougeh

Alumni

Student Alumni

Theodoros Athanasiadis

Soham Basu

Samir Garibov

Shuhei Watanabe

Featured Publications

2024

Rakotoarison, Herilalaina; Adriaensen, Steven; Mallik, Neeratyoy; Garibov, Samir; Bergman, Eddie; Hutter, Frank

In-Context Freeze-Thaw Bayesian Optimization for Hyperparameter Optimization Proceedings Article

In: Proceedings of the 41st International Conference on Machine Learning (ICML), 2024.

All Publications

2025

Lee, Dong Bok; Zhang, Aoxuan Silvia; Kim, Byungjoo; Park, Junhyeon; Adriaensen, Steven; Lee, Juho; Hwang, Sung Ju; Lee, Hae Beom

Cost-Sensitive Freeze-thaw Bayesian Optimization for Efficient Hyperparameter Tuning Proceedings Article

In: 39th Conference on Neural Information Processing Systems (NeurIPS), 2025.

Athanasiadis, Theodoros; Adriaensen, Steven; Müller, Samuel; Hutter, Frank

Tune My Adam, Please! Proceedings Article

In: Proceedings of the Fourth International Conference on Automated Machine Learning (AutoML), Non-Archival Track, 2025.

Lee, Dongwoo; Lee, Dong Bok; Adriaensen, Steven; Lee, Juho; Hwang, Sung Ju; Hutter, Frank; Kim, Seon Joo; Lee, Hae Beom

Bayesian Neural Scaling Laws Extrapolation with Prior-Fitted Networks Proceedings Article

In: Proceedings of the 42nd International Conference on Machine Learning (ICML), 2025.

Carstensen, Timur; Mallik, Neeratyoy; Hutter, Frank; Rapp, Martin

Frozen Layers: Memory-efficient Many-fidelity Hyperparameter Optimization Proceedings Article

In: Proceedings of the Fourth International Conference on Automated Machine Learning (AutoML 2025), Main Track, 2025.

Viering, Tom Julian; Adriaensen, Steven; Rakotoarison, Herilalaina; Müller, Samuel; Hvarfner, Carl; Bakshy, Eytan; Hutter, Frank

$alpha$-PFN: In-Context Learning Entropy Search Proceedings Article

In: The Frontiers in Probabilistic Inference: Sampling meets Learning (FPI) at ICLR, 2025.

Hog, Johannes; Rajan, Raghu; Biedenkapp, André; Awad, Noor; Hutter, Frank; Nguyen, Vu

Meta-learning Population-based Methods for Reinforcement Learning Journal Article

In: Transactions on Machine Learning Research, 2025, ISBN: 2835-8856.

2024

Mallik, Neeratyoy; Janowski, Maciej; Hog, Johannes; Rakotoarison, Herilalaina; Klein, Aaron; Grabocka, Josif; Hutter, Frank

Warmstarting for Scaling Language Models Proceedings Article

In: NeurIPS 2024 Workshop Adaptive Foundation Models, 2024.

Geburek, Anton Merlin; Mallik, Neeratyoy; Stoll, Danny; Bouthillier, Xavier; Hutter, Frank

LMEMs for post-hoc analysis of HPO Benchmarking Proceedings Article

In: Proceedings of the Third International Conference on Automated Machine Learning (AutoML 2024), Workshop Track, 2024.

Watanabe, Shuhei; Mallik, Neeratyoy; Bergman, Edward; Hutter, Frank

Fast Benchmarking of Asynchronous Multi-Fidelity Optimization on Zero-Cost Benchmarks Proceedings Article

In: Proceedings of the Third International Conference on Automated Machine Learning (AutoML 2024), ABCD Track, 2024.

Viering, Tom Julian; Adriaensen, Steven; Rakotoarison, Herilalaina; Hutter, Frank

From Epoch to Sample Size: Developing New Data-driven Priors for Learning Curve Prior-Fitted Networks Proceedings Article

In: Proceedings of the Third International Conference on Automated Machine Learning (AutoML 2024), Workshop Track, 2024.

Rakotoarison, Herilalaina; Adriaensen, Steven; Mallik, Neeratyoy; Garibov, Samir; Bergman, Eddie; Hutter, Frank

In-Context Freeze-Thaw Bayesian Optimization for Hyperparameter Optimization Proceedings Article

In: Proceedings of the 41st International Conference on Machine Learning (ICML), 2024.

2023

Mallik, Neeratyoy; Bergman, Eddie; Hvarfner, Carl; Stoll, Danny; Janowski, Maciej; Lindauer, Marius; Nardi, Luigi; Hutter, Frank

PriorBand: Practical Hyperparameter Optimization in the Age of Deep Learning Proceedings Article

In: Thirty-seventh Conference on Neural Information Processing Systems (NeurIPS), 2023.

Adriaensen, Steven; Rakotoarison, Herilalaina; Müller, Samuel; Hutter, Frank

Efficient Bayesian Learning Curve Extrapolation using Prior-Data Fitted Networks Proceedings Article

In: Thirty-seventh Conference on Neural Information Processing Systems (NeurIPS), 2023.

2022

Adriaensen, Steven; Biedenkapp, André; Shala, Gresa; Awad, Noor; Eimer, Theresa; Lindauer, Marius; Hutter, Frank

Automated Dynamic Algorithm Configuration Journal Article

In: Journal of Artificial Intelligence Research (JAIR), vol. 75, pp. 1633-1699, 2022.

2021

Eggensperger, Katharina; Müller, Philipp; Mallik, Neeratyoy; Feurer, Matthias; Sass, René; Klein, Aaron; Awad, Noor; Lindauer, Marius; Hutter, Frank

HPOBench: A Collection of Reproducible Multi-Fidelity Benchmark Problems for HPO Proceedings Article

In: Vanschoren, J.; Yeung, S. (Ed.): Proceedings of the Neural Information Processing Systems Track on Datasets and Benchmarks, 2021.

Awad, Noor; Mallik, Neeratyoy; Hutter, Frank

DEHB: Evolutionary Hyberband for Scalable, Robust and Efficient Hyperparameter Optimization Proceedings Article

In: Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence (IJCAI'21), ijcai.org, 2021.

Eimer, Theresa; Biedenkapp, André; Reimer, Maximilian; Adriaensen, Steven; Hutter, Frank; Lindauer, Marius

DACBench: A Benchmark Library for Dynamic Algorithm Configuration Proceedings Article

In: Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence (IJCAI'21), ijcai.org, 2021.

2020

Shala, Gresa; Biedenkapp, André; Awad, Noor; Adriaensen, Steven; Lindauer, Marius; Hutter, Frank

Learning Step-Size Adaptation in CMA-ES Proceedings Article

In: Proceedings of the Sixteenth International Conference on Parallel Problem Solving from Nature (PPSN'20), 2020.