Comprehensive Robust Dynamic Mode Decomposition from Mode Extraction to Dimensional Reduction
Yuki Nakamura, Shingo Takemoto, Shunsuke Ono
TL;DR
CR-DMD tackles the robustness problem of Dynamic Mode Decomposition under mixed noise by proposing a two-stage convex framework. The first stage performs a TV-based, convex denoising to enable stable mode extraction, while the second stage crafts a faithful, low-dimensional representation by explicitly linking the robust modes to the original observations via a convex dimensional-reduction problem solved with Preconditioned Primal-Dual Splitting. The approach yields high-accuracy mode extraction and superior low-rank reconstructions on fluid-flow datasets, outperforming RPCA, TLS-DMD, OptDMD, CDMD, and PiDMD, especially under strong noise and outliers. This framework, with its data-fidelity constraints and automatic stepsize selection, offers practical robustness and scalability for spatiotemporal data analysis in noisy environments, and paves the way for integrating convex robustness into operator-centric DMD variants.
Abstract
We propose Comprehensive Robust Dynamic Mode Decomposition (CR-DMD), a novel framework that robustifies the entire DMD process - from mode extraction to dimensional reduction - against mixed noise. Although standard DMD widely used for uncovering spatio-temporal patterns and constructing low-dimensional models of dynamical systems, it suffers from significant performance degradation under noise due to its reliance on least-squares estimation for computing the linear time evolution operator. Existing robust variants typically modify the least-squares formulation, but they remain unstable and fail to ensure faithful low-dimensional representations. First, we introduce a convex optimization-based preprocessing method designed to effectively remove mixed noise, achieving accurate and stable mode extraction. Second, we propose a new convex formulation for dimensional reduction that explicitly links the robustly extracted modes to the original noisy observations, constructing a faithful representation of the original data via a sparse weighted sum of the modes. Both stages are efficiently solved by a preconditioned primal-dual splitting method. Experiments on fluid dynamics datasets demonstrate that CR-DMD consistently outperforms state-of-the-art robust DMD methods in terms of mode accuracy and fidelity of low-dimensional representations under noisy conditions.
