Global Optimization on Graph-Structured Data via Gaussian Processes with Spectral Representations
Shu Hong, Yongsheng Mei, Mahdi Imani, Tian Lan
TL;DR
The paper addresses optimizing an expensive black-box function defined on the nodes of large graphs with partially observed topology. It introduces a global Bayesian optimization framework that builds a GP surrogate in a learned spectral embedding space by first recovering a low-rank surrogate adjacency $\tilde{A}$ via nuclear-norm regularization, then computing spectral embeddings from $\tilde{A}$, and finally applying GP-based BO with a graph-aware spectral kernel. The authors provide non-asymptotic recovery guarantees under both random and deterministic edge sampling, and develop scalable neural-network parameterizations for online learning of the surrogate and embeddings. Empirical results on synthetic (SBM, RDPG) and real-world (Ego-Facebook) graphs demonstrate faster convergence and improved optimization performance over existing graph BO baselines, highlighting the framework's practical impact for tasks like influence maximization, molecular design, and infrastructure optimization on graphs.
Abstract
Bayesian optimization (BO) is a powerful framework for optimizing expensive black-box objectives, yet extending it to graph-structured domains remains challenging due to the discrete and combinatorial nature of graphs. Existing approaches often rely on either full graph topology-impractical for large or partially observed graphs-or incremental exploration, which can lead to slow convergence. We introduce a scalable framework for global optimization over graphs that employs low-rank spectral representations to build Gaussian process (GP) surrogates from sparse structural observations. The method jointly infers graph structure and node representations through learnable embeddings, enabling efficient global search and principled uncertainty estimation even with limited data. We also provide theoretical analysis establishing conditions for accurate recovery of underlying graph structure under different sampling regimes. Experiments on synthetic and real-world datasets demonstrate that our approach achieves faster convergence and improved optimization performance compared to prior methods.
