arXiv Machine Learning

Regime-Conditioned Evaluation in Multi-Context Bayesian Optimization

The paper introduces Regime-Conditioned Evaluation in Multi-Context Bayesian Optimization, arguing that average treatment effect estimates of acquisition strategies overlook critical conditional effects tied to prior quality, budget ratio, and metric. An audit of 40 transfer-BO studies shows that 98% never vary the budget-to-algorithm ratio, leading to unstable rankings—e.g., Greedy outperforms UCB at a low budget but not at a higher one. The authors propose the Portable Regime Score (PRS) to capture this transition, demonstrate its predictive power across 79 diverse conditions, and present RegimePlanner, an online method that adapts acquisition based on PRS and achieves superior performance in HPO-B and GDSC2 benchmarks. whyItMatters":"The study highlights that unconditional rankings of Bayesian optimization methods are unreliable, emphasizing the need to report regime-specific metrics like B/|A| and prior rank correlation to accurately assess acquisition performance."

arXiv Machine Learning
6d ago

StrictPRMBench: A Replayable Evaluation Benchmark for Auditing Fixed-Score PRM Aggregation

StrictPRMBench is a replayable evaluation benchmark designed to audit fixed‑score PRM aggregation rules. It standardizes mathematical reasoning pools, scorer evidence, and deletion interventions so that different reducers confront identical selection problems. Across seven checkpoints and two benchmarks, the benchmark reveals that product aggregation yields higher deletion‑induced selection instability than geometric mean, with statistically significant differences in most cells.

By Pengfei Zheng
arXiv AI
Jun 29

When Is an LLM Worth It for Hyperparameter Optimization? A Budget-Matched Study on Tabular Data Finds the Warm-Start Is a Default Configuration, Not the Model

arXiv:2606. 21641v2 Announce Type: replace-cross Abstract: Large language models (LLMs) have been proposed as hyperparameter-optimization (HPO) advisors that "warm-start" search from prior knowledge, proposing strong configurations in very few evaluations.

By Carson Rodrigues, Oysturn Vas, Isaiah Abner DCosta, Nithish Kumar Prabhakaran
arXiv Machine Learning
Sep 25

Optimal Recovery Meets Bayesian Learning: Where Worst-Case Bounds Pay Off

The paper shows that Worst‑Case Optimal Recovery (OR) and Bayesian learning solve the same Gaussian‑quadratic‑Hilbert problems, linking the radius of information to a nugget‑optimized Gaussian process posterior variance. It evaluates three Bayesian systems, demonstrating that OR can outperform Bayesian methods in certain calibration and reproducibility metrics, yet split‑conformal and other approaches can beat OR in interval scoring, especially under covariate shift. The authors propose matching the guarantee tool to the data regime and auditing that regime first.

By Gordei Verbii