Conference article

Improving Newtonand#8217;s method for Initialization of Modelica models

Johan Ylikiiskilä
Modelon AB, Lund, Sweden

Johan Åkesson
Departement of Automatic Control, Lund University, Sweden

Claus Führer
Departement of Numerical Analysis, Lund University, Sweden

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Published in: Proceedings of the 8th International Modelica Conference; March 20th-22nd; Technical Univeristy; Dresden; Germany

Linköping Electronic Conference Proceedings 63:12, p. 97-104

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Published: 2011-06-30

ISBN: 978-91-7393-096-3

ISSN: 1650-3686 (print), 1650-3740 (online)


Initializing a model written in Modelica translates to nding consistent initial values to the underlyinDAE. Adding initial equations and conditions creates a system of non-linear equations that can be solved for the initial conguration. This pap reports an implementation of Newton’s method to solve the non-linear initialization system. This implementation also uses a regularization method to deal with singular Jacobians as well as sparse solvers to exploit the sparsity structure of the Jacobian. The implementation is based on the opensource projects and Assimulo; KINSOL from the SUNDIALS suite and SuperLU.


Initialization; Newton’s method; regularization;; Assimulo; KINSOL; SuperLU


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