How AD can help solve differential-algebraic equations

Autor: Xiao Li, John D. Pryce, Guangning Tan, Nedialko S. Nedialkov
Rok vydání: 2018
Předmět:
Zdroj: Optimization Methods and Software. 33:729-749
ISSN: 1029-4937
1055-6788
DOI: 10.1080/10556788.2018.1428605
Popis: A characteristic feature of differential-algebraic equations is that one needs to find derivatives of some of\ud their equations with respect to time, as part of the so-called index reduction or regularization, to prepare\ud them for numerical solution. This is often done with the help of a computer algebra system. We show\ud in two significant cases that it can be done efficiently by pure algorithmic differentiation. The first is the\ud Dummy Derivatives method; here we give a mainly theoretical description, with tutorial examples. The\ud second is the solution of a mechanical system directly from its Lagrangian formulation. Here, we outline\ud the theory and show several non-trivial examples of using the ‘Lagrangian facility’ of the Nedialkov–\ud Pryce initial-value solver DAETS, namely a spring-mass-multi-pendulum system; a prescribed-trajectory\ud control problem; and long-time integration of a model of the outer planets of the solar system, taken from\ud the DETEST testing package for ODE solvers.
Databáze: OpenAIRE
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