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Designing Poisson Integrators Through Machine Learning

Miguel Vaquero, David Martín de Diego, Jorge Cortés

TL;DR

The paper addresses designing Poisson integrators that preserve Poisson geometry for integrable Poisson manifolds. It reframes Poisson diffeomorphisms as Lagrangian bisections in a local symplectic groupoid and reduces their construction to solving a Hamilton-Jacobi PDE, which is tackled via a machine-learning-inspired optimization. The key contributions include a general geometric framework, a practical ML-based approximation for the Hamilton-Jacobi equation, and a rigid-body demonstration that preserves the Hamiltonian and Casimir over long time horizons. This approach offers a flexible, geometry-respecting pathway for numerical integration with potential impact in physics and engineering where Poisson structures are central.

Abstract

This paper presents a general method to construct Poisson integrators, i.e., integrators that preserve the underlying Poisson geometry. We assume the Poisson manifold is integrable, meaning there is a known local symplectic groupoid for which the Poisson manifold serves as the set of units. Our constructions build upon the correspondence between Poisson diffeomorphisms and Lagrangian bisections, which allows us to reformulate the design of Poisson integrators as solutions to a certain PDE (Hamilton-Jacobi). The main novelty of this work is to understand the Hamilton-Jacobi PDE as an optimization problem, whose solution can be easily approximated using machine learning related techniques. This research direction aligns with the current trend in the PDE and machine learning communities, as initiated by Physics- Informed Neural Networks, advocating for designs that combine both physical modeling (the Hamilton-Jacobi PDE) and data.

Designing Poisson Integrators Through Machine Learning

TL;DR

The paper addresses designing Poisson integrators that preserve Poisson geometry for integrable Poisson manifolds. It reframes Poisson diffeomorphisms as Lagrangian bisections in a local symplectic groupoid and reduces their construction to solving a Hamilton-Jacobi PDE, which is tackled via a machine-learning-inspired optimization. The key contributions include a general geometric framework, a practical ML-based approximation for the Hamilton-Jacobi equation, and a rigid-body demonstration that preserves the Hamiltonian and Casimir over long time horizons. This approach offers a flexible, geometry-respecting pathway for numerical integration with potential impact in physics and engineering where Poisson structures are central.

Abstract

This paper presents a general method to construct Poisson integrators, i.e., integrators that preserve the underlying Poisson geometry. We assume the Poisson manifold is integrable, meaning there is a known local symplectic groupoid for which the Poisson manifold serves as the set of units. Our constructions build upon the correspondence between Poisson diffeomorphisms and Lagrangian bisections, which allows us to reformulate the design of Poisson integrators as solutions to a certain PDE (Hamilton-Jacobi). The main novelty of this work is to understand the Hamilton-Jacobi PDE as an optimization problem, whose solution can be easily approximated using machine learning related techniques. This research direction aligns with the current trend in the PDE and machine learning communities, as initiated by Physics- Informed Neural Networks, advocating for designs that combine both physical modeling (the Hamilton-Jacobi PDE) and data.
Paper Structure (8 sections, 2 theorems, 7 equations, 2 figures)

This paper contains 8 sections, 2 theorems, 7 equations, 2 figures.

Key Result

Theorem 9

Let $G$ be a symplectic groupoid. Let $L$ be a Lagrangian submanifold of $G$ such that $sou_{|L}: L\rightarrow G_0$ is a (local) diffeomorphism (a Lagrangian bisection). Then

Figures (2)

  • Figure 1: Comparison of the simulated dynamics (blue) and the real trajectory (red) when the initial condition are the points $(1,1,2)$(top plot) and $(3,2,0)$(bottom plot).
  • Figure 2: Top: Evolution of the norm of the difference between the simulated and the real trajectories for $10,000$ iterations with stepsize $0.1$. The difference stays bounded due to the conservation of the underlying geometry. Middle: Evolution of the Hamiltonian when evaluated on the simulated trajectory. The Hamiltonian is almost conserved even for very long trajectories. Bottom: Evolution of the Casimir. The Casimir function is conserved up to rounding error.

Theorems & Definitions (14)

  • Definition 1: Symplectic Manifold
  • Example 1
  • Definition 2: Lagrangian Submanifold
  • Example 2
  • Definition 3: Poisson Manifold
  • Definition 4: Casimir function
  • Definition 5: Poisson Mappings
  • Definition 6: Hamiltonian Vector Field
  • Definition 7: Groupoid
  • Definition 8: Symplectic Groupoid
  • ...and 4 more