Learning discrete Lagrangians for variationalPDEs from data and detection of travelling waves

02/16/2023

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by   Christian Offen, et al.

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The article shows how to learn models of dynamical systems from data which are governed by an unknown variational PDE. Rather than employing reduction techniques, we learn a discrete field theory governed by a discrete Lagrangian density L_d that is modelled as a neural network. Careful regularisation of the loss function for training L_d is necessary to obtain a field theory that is suitable for numerical computations: we derive a regularisation term which optimises the solvability of the discrete Euler–Lagrange equations. Secondly, we develop a method to find solutions to machine learned discrete field theories which constitute travelling waves of the underlying continuous PDE.