Hybrid Dynamics in Modelica: Should all Events be Considered Synchronous

Ramine Nikoukhah
INRIA-Rocquencourt, France

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Ingår i: Proceedings of the 1st International Workshop on Equation-Based Object-Oriented Languages and Tools

Linköping Electronic Conference Proceedings 24:4, s. 37–48

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Publicerad: 2007-07-18

ISBN: 978-91-7519-822-4

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


The Modelica specification is ambiguous as to whether all the events are synchronous are not. Different interpretations are possible leading to considerable differences in the ways models should be constructed and compilers developed. In this paper we examine this issue and show that there exists an interpretation that is more appropriate than others leading to more efficient compilers. It turns out that this interpretation is not the one currently adopted by Dymola but it is closely related to the Scicos formalism.


Modelica; Synchronous language; Scicos; modeling and simulation


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3 A. Benveniste; P. Le Guernic; C. Jacquemot.;"Synchronous programming with events and relations : the Signal language and its semantics"; Science of Computer Programming; 16; 1991; p. 103-149.

4 R. Nikoukhah; “Extensions to Modelica for efficient code generation and separate compilation”; in Proc. EOOLT Workshop at ECOOP’07; Berlin; 2007.

5 P. Fritzson - “Principles of Object-Oriented Modeling and Simulation with Modelica 2.1”; Wiley-IEEE Press; 2003.

6 S. L. Campbell; Jean-Philippe Chancelier and Ramine Nikoukhah; “Modeling and Simulation in Scilab/Scicos”; Springer; 2005.

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