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arXiv 2109.12367math.NAcs.NA
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哈密顿系统的保结构模型降阶

Structure-preserving model order reduction of Hamiltonian systems

J. S. Hesthaven, C. Pagliantini, N. Ripamonti

摘要:

我们讨论了基于投影的模型降阶(MOR)技术针对哈密顿问题的最新发展。哈密尔顿原理完全刻画了数学物理中的许多高维模型,从而产生了丰富的几何结构,在流体动力学、量子力学、光学系统和流行病学模型中都有例子。MOR通过引入低维代理模型,降低了与复杂系统近似相关的计算负担,从而实现高效的多查询数值模拟。然而,标准的简化方法不能保证哈密顿问题的微妙动力学的守恒,导致降阶模型随着时间的推移受到不稳定或精度损失的困扰。通过从辛流形的几何角度来逼近约化过程,得到的降阶模型继承了高维公式的稳定性和守恒性。我们首先介绍了辛几何的一般原理,包括辛向量空间、达布定理和哈密尔顿向量场。这些概念,然后作为一个起点,开发不同的结构保持减少基(RB)算法,包括基于SVD的方法和贪婪技术。我们的结论审查解决减少的问题,不是线性可减少的或在一个非规范的哈密顿形式。

英文摘要:

We discuss the recent developments of projection-based model order reduction (MOR) techniques targeting Hamiltonian problems. Hamilton's principle completely characterizes many high-dimensional models in mathematical physics, resulting in rich geometric structures, with examples in fluid dynamics, quantum mechanics, optical systems, and epidemiological models. MOR reduces the computational burden associated with the approximation of complex systems by introducing low-dimensional surrogate models, enabling efficient multi-query numerical simulations. However, standard reduction approaches do not guarantee the conservation of the delicate dynamics of Hamiltonian problems, resulting in reduced models plagued by instability or accuracy loss over time. By approaching the reduction process from the geometric perspective of symplectic manifolds, the resulting reduced models inherit stability and conservation properties of the high-dimensional formulations. We first introduce the general principles of symplectic geometry, including symplectic vector spaces, Darboux' theorem, and Hamiltonian vector fields. These notions are then used as a starting point to develop different structure-preserving reduced basis (RB) algorithms, including SVD-based approaches and greedy techniques. We conclude the review by addressing the reduction of problems that are not linearly reducible or in a non-canonical Hamiltonian form.

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