Deep Learning Models for Global Coordinate Transformations that Linearize PDEs
This addresses the challenge of solving complex nonlinear PDEs for researchers in computational physics and applied mathematics, though it builds on existing linearization concepts.
The authors tackled the problem of finding coordinate transformations that linearize nonlinear PDEs by developing a deep autoencoder architecture, demonstrating its effectiveness on examples like the Kuramoto-Sivashinsky equation with robust results.
We develop a deep autoencoder architecture that can be used to find a coordinate transformation which turns a nonlinear PDE into a linear PDE. Our architecture is motivated by the linearizing transformations provided by the Cole-Hopf transform for Burgers equation and the inverse scattering transform for completely integrable PDEs. By leveraging a residual network architecture, a near-identity transformation can be exploited to encode intrinsic coordinates in which the dynamics are linear. The resulting dynamics are given by a Koopman operator matrix $\mathbf{K}$. The decoder allows us to transform back to the original coordinates as well. Multiple time step prediction can be performed by repeated multiplication by the matrix $\mathbf{K}$ in the intrinsic coordinates. We demonstrate our method on a number of examples, including the heat equation and Burgers equation, as well as the substantially more challenging Kuramoto-Sivashinsky equation, showing that our method provides a robust architecture for discovering interpretable, linearizing transforms for nonlinear PDEs.