Learning nonlinear dynamical systems from a single trajectory

Abstract

We introduce algorithms for learning nonlinear dynamical systems of the form $x_{t+1}=\sigma ({\Theta }^{\star }{x}_t)+{\epsilon }_t$, where ${\Theta }^{\star }$ is a weight matrix, $\sigma$ is a nonlinear link function, and ${\epsilon }_t$ is a mean-zero noise process. We give an algorithm that recovers the weight matrix ${\Theta }^{\star }$ from a single trajectory with optimal sample complexity and linear running time. The algorithm succeeds under weaker statistical assumptions than in previous work, and in particular i) does not require a bound on the spectral norm of the weight matrix ${\Theta }^{\star }$ (rather, it depends on a generalization of the spectral radius) and ii) enjoys guarantees for non-strictly-increasing link functions such as the ReLU. Our analysis has two key components: i) we give a general recipe whereby global stability for nonlinear dynamical systems can be used to certify that the state-vector covariance is well-conditioned, and ii) using these tools, we extend well-known algorithms for efficiently learning generalized linear models to the dependent setting.

To appear at L4DC 2020

References in corpus (1)

• Efficient Learning of Generalized Linear and Single Index Models with Isotonic Regression

Cited by in corpus (1)

• Active Learning for Nonlinear System Identification with Guarantees