Multi-Objective Bayesian Optimization via Adaptive \varepsilon-Constraints Decomposition
For practitioners optimizing expensive black-box functions with multiple objectives, STAGE-BO offers better Pareto coverage without hypervolume computation, but the gains are incremental over existing methods.
STAGE-BO improves Pareto front coverage in multi-objective Bayesian optimization by identifying and targeting geometric gaps via adaptive ε-constraints, achieving superior coverage and competitive hypervolume on benchmarks.
Multi-objective Bayesian optimization (MOBO) provides a principled framework for optimizing expensive black-box functions with multiple objectives. However, existing MOBO methods often struggle with coverage, scalability with respect to the number of objectives, and integrating constraints and preferences. In this work, we propose \textit{STAGE-BO, Sequential Targeting Adaptive Gap-Filling $\varepsilon$-Constraint Bayesian Optimization}, that explicitly targets under-explored regions of the Pareto front. By analyzing the coverage of the approximate Pareto front, our method identifies the largest geometric gaps. These gaps are then used as constraints, which transforms the problem into a sequence of inequality-constrained subproblems, efficiently solved via constrained expected improvement acquisition. Our approach provides a uniform Pareto coverage without hypervolume computation and naturally applies to constrained and preference-based settings. Experiments on synthetic and real-world benchmarks demonstrate superior coverage and competitive hypervolume performance against state-of-the-art baselines.