🤖 AI Summary
This study addresses parameter uncertainty in high-dimensional hyperbolic inverse problems for tsunami early warning by reformulating Bayesian optimal experimental design (OED) as a dense submatrix selection problem in data space. The authors propose a pipelined multi-GPU greedy algorithm based on Schur complement updates, which fully overlaps computation and I/O and overcomes the limitations of conventional low-rank approximations in hyperbolic systems. Demonstrating near-perfect weak and strong scaling on the Perlmutter and Frontier supercomputers, the method efficiently optimizes the placement of 175 sensors in the Cascadia Subduction Zone digital twin, handling parameter fields with over one billion degrees of freedom.
📝 Abstract
Real-time tsunami early warning relies on distributed sensor networks to infer seismic sources and seafloor motion. Optimizing these networks via Bayesian optimal experimental design (OED) is exceptionally challenging for systems governed by hyperbolic partial differential equations, which lack the spectral decay required by standard low-rank approximations. We present a scalable Bayesian OED framework for linear time-invariant systems. By reformulating the inverse problem in the data space, we transform OED into dense matrix subset selection. We propose a multi-GPU, Schur-complement-update-based, greedy algorithm that solves the OED problem using a pipelined approach that fully overlaps I/O with GPU computations. Our framework achieves near-perfect weak and strong scaling across hundreds of GPUs on Perlmutter and Frontier. Applied to the 2025 Gordon Bell Prize-winning digital twin for tsunami forecasting in the Cascadia Subduction Zone, we optimize a 175-sensor network, minimizing the uncertainty of a parameter field with over one billion degrees of freedom.