arXiv Machine Learning By Emiel Witting, Cheng Yan, Tom Julian Viering

Simple Meta-Learning for HPO and CASH Using Performance Representations

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The paper proposes a new meta‑learning representation for hyperparameter optimization (HPO) and combined algorithm selection and hyperparameter optimization (CASH) that encodes each configuration by its historical performance across prior tasks, rather than by explicit hyperparameter values. This performance‑based representation can be used with standard surrogate models, such as linear Bayesian ridge regression, and is applied to a diversity‑based re‑ranking criterion (maximal marginal relevance) as a posterior‑free acquisition rule. Experiments on the TabArena benchmark show that this approach outperforms dedicated meta‑learning baselines, achieving comparable tuned performance in about half the number of trials, and remains competitive for single‑model HPO while scaling independently of search‑space dimensionality.

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