Special Session 79: Recent Advancements in the Numerical Analysis of Nonlinear Partial Differential Equations

ISALT: Inference-based schemes adaptive to large time-stepping for locally Lipschitz ergodic systems

Xingjie Li
University of North Carolina Charlotte
USA
Co-Author(s):    Xingjie Helen Li and Fei Lu and Molei Tao and Xiaofeng Felix Ye
Abstract:
Efficient simulation of SDEs is essential in many applications, particularly for ergodic systems that demand efficient simulation of both short-time dynamics and large-time statistics. However, locally Lipschitz SDEs often require special treatments such as implicit schemes with small time-steps to accurately simulate the ergodic measures. We introduce a framework to construct inference-based schemes adaptive to large time-steps (ISALT) from data, achieving a reduction in time by several orders of magnitudes. The key is the statistical learning of an approximation to the infinite-dimensional discrete-time flow map. We explore the use of numerical schemes (such as the Euler-Maruyama, the hybrid RK4, and an implicit scheme) to derive informed basis functions, leading to a parameter inference problem. We introduce a scalable algorithm to estimate the parameters by least squares, and we prove the convergence of the estimators as data size increases.