Discontinuities handled with events in Assimulo

Emil Fredriksson, Christian Andersson, Johan Åkesson

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceedingpeer-review

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Often integrating ordinary differential equations or differential algebraic equations (DAE) do not constitute the problem alone. A common complement is finding the root of an algebraic function (an event function) that depends on the states of the problem. This formulation of a model enables the possibility of including discontinuities, an important part of the Functional Mock-up Interface standard which allows hybrid models of differential algebraic equations. The problem of root-finding during integration is however difficult. Both in a theoretical aspect and as a software problem.

An implementation of software for root-finding is done in Assimulo, a Python/Cython wrapper for integrators. The implementation takes the Functional Mock-up Interface standard into consideration. The implementation is made usable for a wide variety of integration algorithms and is also verified and benchmarked with advanced industrial models, showing good indications of being robust and scaling well for large systems.
Original languageEnglish
Title of host publicationLinköping Electronic Conference Proceedings
EditorsHubertus Tummescheit, Karl-Erik Årzén
PublisherLinköping University Electronic Press
Number of pages10
Publication statusPublished - 2014
Event10th International Modelica Conference - Lund, Sweden
Duration: 2014 Mar 102014 Mar 12

Publication series

ISSN (Print)1650-3686
ISSN (Electronic)1650-3740


Conference10th International Modelica Conference

Bibliographical note

The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Numerical Analysis (011015004), Department of Automatic Control (011017000)

Subject classification (UKÄ)

  • Mathematics
  • Control Engineering


  • Assimulo
  • FMI
  • Functional Mock-up Interface
  • FMU
  • Discontinuities
  • Events
  • Root-finding


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