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Alexander Tornede

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9 papers

2 author rows

JMLR Journal 2025 Journal Article

DeepCAVE: A Visualization and Analysis Tool for Automated Machine Learning

Sarah Segel
Helena Graf
Edward Bergman
Kristina Thieme
Marcel Wever
Alexander Tornede
Frank Hutter
Marius Lindauer

Hyperparameter optimization (HPO), as a central paradigm of AutoML, is crucial for leveraging the full potential of machine learning (ML) models; yet its complexity poses challenges in understanding and debugging the optimization process. We present DeepCAVE, a tool for interactive visualization and analysis, providing insights into HPO. Through an interactive dashboard, researchers, data scientists, and ML engineers can explore various aspects of the HPO process and identify issues, untouched potentials, and new insights about the ML model being tuned. By empowering users with actionable insights, DeepCAVE contributes to the interpretability of HPO and ML on a design level and aims to foster the development of more robust and efficient methodologies in the future. [abs] [ pdf ][ bib ] [ code ] &copy JMLR 2025. ( edit, beta )

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TMLR Journal 2024 Journal Article

AutoML in the Age of Large Language Models: Current Challenges, Future Opportunities and Risks

Alexander Tornede
Difan Deng
Theresa Eimer
Joseph Giovanelli
Aditya Mohan
Tim Ruhkopf
Sarah Segel
Daphne Theodorakopoulos

The fields of both Natural Language Processing (NLP) and Automated Machine Learning (AutoML) have achieved remarkable results over the past years. In NLP, especially Large Language Models (LLMs) have experienced a rapid series of breakthroughs very recently. We envision that the two fields can radically push the boundaries of each other through tight integration. To showcase this vision, we explore the potential of a symbiotic relationship between AutoML and LLMs, shedding light on how they can benefit each other. In particular, we investigate both the opportunities to enhance AutoML approaches with LLMs from different perspectives and the challenges of leveraging AutoML to further improve LLMs. To this end, we survey existing work, and we critically assess risks. We strongly believe that the integration of the two fields has the potential to disrupt both fields, NLP and AutoML. By highlighting conceivable synergies, but also risks, we aim to foster further exploration at the intersection of AutoML and LLMs.

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AAAI Conference 2024 Conference Paper

Interactive Hyperparameter Optimization in Multi-Objective Problems via Preference Learning

Joseph Giovanelli
Alexander Tornede
Tanja Tornede
Marius Lindauer

Hyperparameter optimization (HPO) is important to leverage the full potential of machine learning (ML). In practice, users are often interested in multi-objective (MO) problems, i.e., optimizing potentially conflicting objectives, like accuracy and energy consumption. To tackle this, the vast majority of MO-ML algorithms return a Pareto front of non-dominated machine learning models to the user. Optimizing the hyperparameters of such algorithms is non-trivial as evaluating a hyperparameter configuration entails evaluating the quality of the resulting Pareto front. In literature, there are known indicators that assess the quality of a Pareto front (e.g., hypervolume, R2) by quantifying different properties (e.g., volume, proximity to a reference point). However, choosing the indicator that leads to the desired Pareto front might be a hard task for a user. In this paper, we propose a human-centered interactive HPO approach tailored towards multi-objective ML leveraging preference learning to extract desiderata from users that guide the optimization. Instead of relying on the user guessing the most suitable indicator for their needs, our approach automatically learns an appropriate indicator. Concretely, we leverage pairwise comparisons of distinct Pareto fronts to learn such an appropriate quality indicator. Then, we optimize the hyperparameters of the underlying MO-ML algorithm towards this learned indicator using a state-of-the-art HPO approach. In an experimental study targeting the environmental impact of ML, we demonstrate that our approach leads to substantially better Pareto fronts compared to optimizing based on a wrong indicator pre-selected by the user, and performs comparable in the case of an advanced user knowing which indicator to pick.

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ICML Conference 2024 Conference Paper

Position: A Call to Action for a Human-Centered AutoML Paradigm

Marius Lindauer
Florian Karl
Anne Klier
Julia Moosbauer
Alexander Tornede
Andreas Müller 0024
Frank Hutter
Matthias Feurer 0001

Automated machine learning (AutoML) was formed around the fundamental objectives of automatically and efficiently configuring machine learning (ML) workflows, aiding the research of new ML algorithms, and contributing to the democratization of ML by making it accessible to a broader audience. Over the past decade, commendable achievements in AutoML have primarily focused on optimizing predictive performance. This focused progress, while substantial, raises questions about how well AutoML has met its broader, original goals. In this position paper, we argue that a key to unlocking AutoML’s full potential lies in addressing the currently underexplored aspect of user interaction with AutoML systems, including their diverse roles, expectations, and expertise. We envision a more human-centered approach in future AutoML research, promoting the collaborative design of ML systems that tightly integrates the complementary strengths of human expertise and AutoML methodologies.

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IJCAI Conference 2023 Conference Paper

A Survey of Methods for Automated Algorithm Configuration (Extended Abstract)

Elias Schede
Jasmin Brandt
Alexander Tornede
Marcel Wever
Viktor Bengs
Eyke Hüllermeier
Kevin Tierney

Algorithm configuration (AC) is concerned with the automated search of the most suitable parameter configuration of a parametrized algorithm. There are currently a wide variety of AC problem variants and methods proposed in the literature. Existing reviews do not take into account all derivatives of the AC problem, nor do they offer a complete classification scheme. To this end, we introduce taxonomies to describe the AC problem and features of configuration methods, respectively. Existing AC literature is classified and characterized by the provided taxonomies.

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TMLR Journal 2023 Journal Article

MASIF: Meta-learned Algorithm Selection using Implicit Fidelity Information

Tim Ruhkopf
Aditya Mohan
Difan Deng
Alexander Tornede
Frank Hutter
Marius Lindauer

Selecting a well-performing algorithm for a given task or dataset can be time-consuming and tedious, but is crucial for the successful day-to-day business of developing new AI & ML applications. Algorithm Selection (AS) mitigates this through a meta-model leveraging meta-information about previous tasks. However, most of the available AS methods are error-prone because they characterize a task by either cheap-to-compute properties of the dataset or evaluations of cheap proxy algorithms, called landmarks. In this work, we extend the classical AS data setup to include multi-fidelity information and empirically demonstrate how meta-learning on algorithms’ learning behaviour allows us to exploit cheap test-time evidence effectively and combat myopia significantly. We further postulate a budget-regret trade-off w.r.t. the selection process. Our new selector MASIF is able to jointly interpret online evidence on a task in form of varying-length learning curves without any parametric assumption by leveraging a transformer-based encoder. This opens up new possibilities for guided rapid prototyping in data science on cheaply observed partial learning curves.

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JAIR Journal 2023 Journal Article

Towards Green Automated Machine Learning: Status Quo and Future Directions

Tanja Tornede
Alexander Tornede
Jonas Hanselle
Felix Mohr
Marcel Wever
Eyke Hüllermeier

Automated machine learning (AutoML) strives for the automatic configuration of machine learning algorithms and their composition into an overall (software) solution — a machine learning pipeline — tailored to the learning task (dataset) at hand. Over the last decade, AutoML has developed into an independent research field with hundreds of contributions. At the same time, AutoML is being criticized for its high resource consumption as many approaches rely on the (costly) evaluation of many machine learning pipelines, as well as the expensive large-scale experiments across many datasets and approaches. In the spirit of recent work on Green AI, this paper proposes Green AutoML, a paradigm to make the whole AutoML process more environmentally friendly. Therefore, we first elaborate on how to quantify the environmental footprint of an AutoML tool. Afterward, different strategies on how to design and benchmark an AutoML tool w.r.t. their “greenness”, i.e., sustainability, are summarized. Finally, we elaborate on how to be transparent about the environmental footprint and what kind of research incentives could direct the community in a more sustainable AutoML research direction. As part of this, we propose a sustainability checklist to be attached to every AutoML paper featuring all core aspects of Green AutoML.

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JAIR Journal 2022 Journal Article

A Survey of Methods for Automated Algorithm Configuration

Elias Schede
Jasmin Brandt
Alexander Tornede
Marcel Wever
Viktor Bengs
Eyke Hüllermeier
Kevin Tierney

Algorithm configuration (AC) is concerned with the automated search of the most suitable parameter configuration of a parametrized algorithm. There is currently a wide variety of AC problem variants and methods proposed in the literature. Existing reviews do not take into account all derivatives of the AC problem, nor do they offer a complete classification scheme. To this end, we introduce taxonomies to describe the AC problem and features of configuration methods, respectively. We review existing AC literature within the lens of our taxonomies, outline relevant design choices of configuration approaches, contrast methods and problem variants against each other, and describe the state of AC in industry. Finally, our review provides researchers and practitioners with a look at future research directions in the field of AC.

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AAAI Conference 2022 Conference Paper

Machine Learning for Online Algorithm Selection under Censored Feedback

Alexander Tornede
Viktor Bengs
Eyke Hüllermeier

In online algorithm selection (OAS), instances of an algorithmic problem class are presented to an agent one after another, and the agent has to quickly select a presumably best algorithm from a fixed set of candidate algorithms. For decision problems such as satisfiability (SAT), quality typically refers to the algorithm’s runtime. As the latter is known to exhibit a heavy-tail distribution, an algorithm is normally stopped when exceeding a predefined upper time limit. As a consequence, machine learning methods used to optimize an algorithm selection strategy in a data-driven manner need to deal with right-censored samples, a problem that has received little attention in the literature so far. In this work, we revisit multi-armed bandit algorithms for OAS and discuss their capability of dealing with the problem. Moreover, we adapt them towards runtime-oriented losses, allowing for partially censored data while keeping a space- and time-complexity independent of the time horizon. In an extensive experimental evaluation on an adapted version of the ASlib benchmark, we demonstrate that theoretically well-founded methods based on Thompson sampling perform specifically strong and improve in comparison to existing methods.

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