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SunBURST: Deterministic GPU-Accelerated Bayesian Evidence via Mode-Centric Laplace Integration

Ira Wolfson

TL;DR

SunBURST introduces a deterministic, GPU-accelerated method for Bayesian evidence that leverages mode-centric Laplace integration rather than global volume exploration. By discovering posterior modes via radial rays, refining them with batched L-BFGS, and computing per-mode evidence through the Laplace approximation, SunBURST achieves near-constant or sub-linear wall-clock scaling with dimension and exact results for Gaussian posteriors up to 1024 dimensions. Its GPU-enabled parallelism enables dramatic speedups over traditional nested sampling, delivering machine-precision evidence in seconds for Gaussian-like posteriors and a substantial practical advantage for high-dimensional model comparison. While highly effective for near-Gaussian posteriors common in physics and engineering, SunBURST's accuracy degrades for strongly non-Gaussian posteriors, where it serves best as a fast, geometry-aware estimator or preprocessing step for hybrid workflows. The work demonstrates that high-precision Bayesian evidence can be made tractable in very high dimensions through deterministic, GPU-parallel integration focused on local Gaussian structure around a finite set of modes.

Abstract

Bayesian evidence evaluation becomes computationally prohibitive in high dimensions due to the curse of dimensionality and the sequential nature of sampling-based methods. We introduce SunBURST, a deterministic GPU-native algorithm for Bayesian evidence calculation that replaces global volume exploration with mode-centric geometric integration. The pipeline combines radial mode discovery, batched L-BFGS refinement, and Laplace-based analytic integration, treating modes independently and converting large batches of likelihood evaluations into massively parallel GPU workloads. For Gaussian and near-Gaussian posteriors, where the Laplace approximation is exact or highly accurate, SunBURST achieves numerical agreement at double-precision tolerance in dimensions up to 1024 in our benchmarks, with sub-linear wall-clock scaling across the tested range. In multimodal Gaussian mixtures, conservative configurations yield sub-percent accuracy while maintaining favorable scaling. SunBURST is not intended as a universal replacement for sampling-based inference. Its design targets regimes common in physical parameter estimation and inverse problems, where posterior mass is locally well approximated by Gaussian structure around a finite number of modes. In strongly non-Gaussian settings, the method can serve as a fast geometry-aware evidence estimator or as a preprocessing stage for hybrid workflows. These results show that high-precision Bayesian evidence evaluation can be made computationally tractable in very high dimensions through deterministic integration combined with massive parallelism.

SunBURST: Deterministic GPU-Accelerated Bayesian Evidence via Mode-Centric Laplace Integration

TL;DR

SunBURST introduces a deterministic, GPU-accelerated method for Bayesian evidence that leverages mode-centric Laplace integration rather than global volume exploration. By discovering posterior modes via radial rays, refining them with batched L-BFGS, and computing per-mode evidence through the Laplace approximation, SunBURST achieves near-constant or sub-linear wall-clock scaling with dimension and exact results for Gaussian posteriors up to 1024 dimensions. Its GPU-enabled parallelism enables dramatic speedups over traditional nested sampling, delivering machine-precision evidence in seconds for Gaussian-like posteriors and a substantial practical advantage for high-dimensional model comparison. While highly effective for near-Gaussian posteriors common in physics and engineering, SunBURST's accuracy degrades for strongly non-Gaussian posteriors, where it serves best as a fast, geometry-aware estimator or preprocessing step for hybrid workflows. The work demonstrates that high-precision Bayesian evidence can be made tractable in very high dimensions through deterministic, GPU-parallel integration focused on local Gaussian structure around a finite set of modes.

Abstract

Bayesian evidence evaluation becomes computationally prohibitive in high dimensions due to the curse of dimensionality and the sequential nature of sampling-based methods. We introduce SunBURST, a deterministic GPU-native algorithm for Bayesian evidence calculation that replaces global volume exploration with mode-centric geometric integration. The pipeline combines radial mode discovery, batched L-BFGS refinement, and Laplace-based analytic integration, treating modes independently and converting large batches of likelihood evaluations into massively parallel GPU workloads. For Gaussian and near-Gaussian posteriors, where the Laplace approximation is exact or highly accurate, SunBURST achieves numerical agreement at double-precision tolerance in dimensions up to 1024 in our benchmarks, with sub-linear wall-clock scaling across the tested range. In multimodal Gaussian mixtures, conservative configurations yield sub-percent accuracy while maintaining favorable scaling. SunBURST is not intended as a universal replacement for sampling-based inference. Its design targets regimes common in physical parameter estimation and inverse problems, where posterior mass is locally well approximated by Gaussian structure around a finite number of modes. In strongly non-Gaussian settings, the method can serve as a fast geometry-aware evidence estimator or as a preprocessing stage for hybrid workflows. These results show that high-precision Bayesian evidence evaluation can be made computationally tractable in very high dimensions through deterministic integration combined with massive parallelism.
Paper Structure (103 sections, 47 equations, 1 figure, 10 tables)

This paper contains 103 sections, 47 equations, 1 figure, 10 tables.

Figures (1)

  • Figure 1: Wall-clock scaling comparison on Gaussian posteriors. SunBURST (dark red circles) maintains near-constant runtime through 64 dimensions before transitioning to $O(d^{1.0})$ scaling. All competitors exhibit exponential growth: dynesty variants timeout beyond 32--64D, UltraNest beyond 8D. Shaded regions indicate dimensions where only SunBURST achieves each accuracy level. SunBURST achieves 1024D in 6.8 seconds.