---
_id: '29240'
abstract:
- lang: eng
  text: "The principle of least action is one of the most fundamental physical principle.
    It says that among all possible motions connecting two points in a phase space,
    the system will exhibit those motions which extremise an action functional. Many
    qualitative features of dynamical systems, such as the presence of conservation
    laws and energy balance equations, are related to the existence of an action functional.
    Incorporating variational structure into learning algorithms for dynamical systems
    is, therefore, crucial in order to make sure that the learned model shares important
    features with the exact physical system. In this paper we show how to incorporate
    variational principles into trajectory predictions of learned dynamical systems.
    The novelty of this work is that (1) our technique relies only on discrete position
    data of observed trajectories. Velocities or conjugate momenta do not need to
    be observed or approximated and no prior knowledge about the form of the variational
    principle is assumed. Instead, they are recovered using backward error analysis.
    (2) Moreover, our technique compensates discretisation errors when trajectories
    are computed from the learned system. This is important when moderate to large
    step-sizes are used and high accuracy is required. For this,\r\nwe introduce and
    rigorously analyse the concept of inverse modified Lagrangians by developing an
    inverse version of variational backward error analysis. (3) Finally, we introduce
    a method to perform system identification from position observations only, based
    on variational backward error analysis."
article_type: original
author:
- first_name: Sina
  full_name: Ober-Blöbaum, Sina
  id: '16494'
  last_name: Ober-Blöbaum
- first_name: Christian
  full_name: Offen, Christian
  id: '85279'
  last_name: Offen
  orcid: 0000-0002-5940-8057
citation:
  ama: Ober-Blöbaum S, Offen C. Variational Learning of Euler–Lagrange Dynamics from
    Data. <i>Journal of Computational and Applied Mathematics</i>. 2023;421:114780.
    doi:<a href="https://doi.org/10.1016/j.cam.2022.114780">10.1016/j.cam.2022.114780</a>
  apa: Ober-Blöbaum, S., &#38; Offen, C. (2023). Variational Learning of Euler–Lagrange
    Dynamics from Data. <i>Journal of Computational and Applied Mathematics</i>, <i>421</i>,
    114780. <a href="https://doi.org/10.1016/j.cam.2022.114780">https://doi.org/10.1016/j.cam.2022.114780</a>
  bibtex: '@article{Ober-Blöbaum_Offen_2023, title={Variational Learning of Euler–Lagrange
    Dynamics from Data}, volume={421}, DOI={<a href="https://doi.org/10.1016/j.cam.2022.114780">10.1016/j.cam.2022.114780</a>},
    journal={Journal of Computational and Applied Mathematics}, publisher={Elsevier},
    author={Ober-Blöbaum, Sina and Offen, Christian}, year={2023}, pages={114780}
    }'
  chicago: 'Ober-Blöbaum, Sina, and Christian Offen. “Variational Learning of Euler–Lagrange
    Dynamics from Data.” <i>Journal of Computational and Applied Mathematics</i> 421
    (2023): 114780. <a href="https://doi.org/10.1016/j.cam.2022.114780">https://doi.org/10.1016/j.cam.2022.114780</a>.'
  ieee: 'S. Ober-Blöbaum and C. Offen, “Variational Learning of Euler–Lagrange Dynamics
    from Data,” <i>Journal of Computational and Applied Mathematics</i>, vol. 421,
    p. 114780, 2023, doi: <a href="https://doi.org/10.1016/j.cam.2022.114780">10.1016/j.cam.2022.114780</a>.'
  mla: Ober-Blöbaum, Sina, and Christian Offen. “Variational Learning of Euler–Lagrange
    Dynamics from Data.” <i>Journal of Computational and Applied Mathematics</i>,
    vol. 421, Elsevier, 2023, p. 114780, doi:<a href="https://doi.org/10.1016/j.cam.2022.114780">10.1016/j.cam.2022.114780</a>.
  short: S. Ober-Blöbaum, C. Offen, Journal of Computational and Applied Mathematics
    421 (2023) 114780.
date_created: 2022-01-11T13:24:00Z
date_updated: 2023-08-10T08:42:39Z
ddc:
- '510'
department:
- _id: '636'
doi: 10.1016/j.cam.2022.114780
external_id:
  arxiv:
  - '2112.12619'
file:
- access_level: open_access
  content_type: application/pdf
  creator: coffen
  date_created: 2022-06-28T15:25:50Z
  date_updated: 2022-06-28T15:25:50Z
  description: |-
    The principle of least action is one of the most fundamental physical principle. It says that among all possible motions
    connecting two points in a phase space, the system will exhibit those motions which extremise an action functional.
    Many qualitative features of dynamical systems, such as the presence of conservation laws and energy balance equa-
    tions, are related to the existence of an action functional. Incorporating variational structure into learning algorithms
    for dynamical systems is, therefore, crucial in order to make sure that the learned model shares important features
    with the exact physical system. In this paper we show how to incorporate variational principles into trajectory predic-
    tions of learned dynamical systems. The novelty of this work is that (1) our technique relies only on discrete position
    data of observed trajectories. Velocities or conjugate momenta do not need to be observed or approximated and no
    prior knowledge about the form of the variational principle is assumed. Instead, they are recovered using backward
    error analysis. (2) Moreover, our technique compensates discretisation errors when trajectories are computed from the
    learned system. This is important when moderate to large step-sizes are used and high accuracy is required. For this,
    we introduce and rigorously analyse the concept of inverse modified Lagrangians by developing an inverse version of
    variational backward error analysis. (3) Finally, we introduce a method to perform system identification from position
    observations only, based on variational backward error analysis.
  file_id: '32274'
  file_name: ShadowLagrangian_revision1_journal_style_arxiv.pdf
  file_size: 3640770
  relation: main_file
  title: Variational Learning of Euler–Lagrange Dynamics from Data
file_date_updated: 2022-06-28T15:25:50Z
has_accepted_license: '1'
intvolume: '       421'
keyword:
- Lagrangian learning
- variational backward error analysis
- modified Lagrangian
- variational integrators
- physics informed learning
language:
- iso: eng
oa: '1'
page: '114780'
publication: Journal of Computational and Applied Mathematics
publication_identifier:
  issn:
  - 0377-0427
publication_status: epub_ahead
publisher: Elsevier
quality_controlled: '1'
related_material:
  link:
  - relation: software
    url: https://github.com/Christian-Offen/LagrangianShadowIntegration
status: public
title: Variational Learning of Euler–Lagrange Dynamics from Data
type: journal_article
user_id: '85279'
volume: 421
year: '2023'
...
