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

Ladda ner artikelhttp://dx.doi.org/10.3384/ecp1106397

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

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

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Publicerad: 2011-06-30

ISBN: 978-91-7393-096-3

ISSN: 1650-3686 (tryckt), 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 Jmodelica.org and Assimulo; KINSOL from the SUNDIALS suite and SuperLU.


Initialization; Newton’s method; regularization; Jmodelica.org; Assimulo; KINSOL; SuperLU


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