A Riemannian Framework for Learning Reduced-order Lagrangian Dynamics
Katharina Friedl, No\'emie Jaquier, Jens Lundell, Tamim Asfour, Danica, Kragic

TL;DR
This paper introduces a Riemannian geometric neural network architecture that learns physically consistent reduced-order models, enabling accurate long-term predictions of complex high-dimensional systems with improved data efficiency.
Contribution
It proposes a novel Riemannian framework for learning reduced-order Lagrangian dynamics that preserves physical structure and improves model interpretability and efficiency.
Findings
Accurately predicts high-dimensional system dynamics long-term.
Learns physically plausible reduced models with less data.
Applicable to rigid and deformable systems.
Abstract
By incorporating physical consistency as inductive bias, deep neural networks display increased generalization capabilities and data efficiency in learning nonlinear dynamic models. However, the complexity of these models generally increases with the system dimensionality, requiring larger datasets, more complex deep networks, and significant computational effort. We propose a novel geometric network architecture to learn physically-consistent reduced-order dynamic parameters that accurately describe the original high-dimensional system behavior. This is achieved by building on recent advances in model-order reduction and by adopting a Riemannian perspective to jointly learn a non-linear structure-preserving latent space and the associated low-dimensional dynamics. Our approach enables accurate long-term predictions of the high-dimensional dynamics of rigid and deformable systems with…
Peer Reviews
Decision·ICLR 2025 Poster
The overall structure of RO-LNN is visualized well in Fig. 1, and the authors put great effort into explaining their architectures and learning algorithms that contain lots of equations in the limited space.
It seems like the overall idea of learning ROM using constrained AE that preserves the Lagrangian structure is already presented in [Buchfink et al.] cited in the paper. However, this is not clearly pointed out in the paper, and the authors' claims in the introduction and their explanation of the methodology in Section 3&4 somehow mislead the readers to think that the idea is also the main contribution of this paper. This reviewer thinks this paper's contribution on top of the prior work is prop
1. The paper presents experimental results on increasing complexity of the case 2. It shows better results compared to Lagrangian Neural Network
Major: 1. It is unclear where the novelty of the idea lies and what advantage it brings with respect to the previous works. The use of auto-encoder to reduce the dimensionality of the system is not a new idea. In fact, several papers in the same field like Hamiltonian Neural Network, Lagrangian Neural Network also used auto-encoder to learn dynamics of systems from images. If I understand it correctly, the novelty of the idea lies in a neural network learning both the mass matrix and potential f
The strengths are listed as followed - Utilizes geometry and physics as inductive biases, leading to a physically consistent model to improve the interpretability. - Effectively learns reduced-order dynamics for high-dimensional rigid and deformable systems with accurate long-term predictions. - Joint optimization of latent space and reduced dynamic parameters enhances performance, particularly in low-data regimes. - Incorporates intrinsic geometry of the problem, aiding in the preservation of
### Contribution and Originality - I question the novelty of this paper. The proposed approach closely resembles existing methods described in [1, 2]. Additionally, the authors have not cited reference [1], which appears to be highly relevant to their work. - The contribution of this paper is overstated, and the true contribution appears to be quite incremental. Based on my understanding, the theoretical foundation relies heavily on the published work in [2], with many of the equations direct
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Taxonomy
TopicsModel Reduction and Neural Networks · Neural Networks and Applications · Gaussian Processes and Bayesian Inference
