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I have a problem regarding solving the model in DAE mode. I need to know the procedure for the activation of the DAE flag in Dymola 2019.

karel
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Alireza Masoom
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1 Answers1

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That is described in the release notes:

3.3 Simulating a model

3.3.1 DAE Mode
Dymola 2019 supports DAE (Differential-Algebraic Equations) mode. DAE mode is activated by setting the flag 

Advanced.Define.DAEsolver = true

DAE mode is supported by the integrators Dassl, Radau IIa, Esdirk23a, Esdirk34a, Esdirk45a, and Sdirk34hw. (The flag is by default false.)

Note that there has been improvements in the mode for Dymola 2020 and that not all models benefit from DAE-mode.

See also the conference paper: https://modelica.org/events/modelica2019/proceedings/html/papers/Modelica2019paper4D1.pdf

Hans Olsson
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  • Is this DAE mode gonna cause an initialization failure in some cases? – Jack Jun 27 '20 at 18:20
  • At least with Dymola 2020 or later it shouldn't cause any new initialization failures as initialization (and events) use the non-DAE variant of the equations. As explained in section 3.3 of the paper there are some issues for event localization - but initialization avoids that. – Hans Olsson Jul 06 '20 at 08:08