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Dummy derivatives, automatic differentiation and external functions

Dummy derivatives, automatic differentiation and external functions

Hello everybody,

Reading Mattsson, Sven Erik and Söderlind, Gustaf: Index reduction in differential-algebraic equations using dummy derivatives, SIAM J. Sci. Comput., url = http://dx.doi.org/10.1137/0914043; I understand the OM implementation of the dummy derivatives method uses automatic differentiation.

Modelica allows calling functions from third-party DLLs. In that case, it's not possible to do operator oveloading nor re-write functions because of we don't have access to the sources.

In this case, does OM uses symbolic differentiation or maybe a mix of symbolic, numeric and automatic differentiation?

Thanks!!!!


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Re: Dummy derivatives, automatic differentiation and external functions

Hi,

if OM needs to differentiate an equations for the index reduction purpose it is done by symbolically.
In case the specific equation contains an external function call the user may provide derivative information
via annotations. Otherwise OM has no chance and will fail, currently.

so long.
Willi

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