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Is BLT-transformation default in OM?

Is BLT-transformation default in OM?


I have a couple of questions regarding the structural analysis and some general compiler things.

Does OM apply the BLT equations sorting algorithm by Tarjan? Is this default?

Does OM apply some more structural analysis within the BLT-blocks, e.g. Tearing?

Finally how can I output information about a compiled model? There is a model that gives different simulation results depending on the which order the equations are written. (Both results are wrong).

Thanks Alot!



Re: Is BLT-transformation default in OM?

Hello patrik,

Yes, the omc is applying the BLT by default.

A version of tearing is implemented, but not activated by default, because it hasn't currently the robustness and high performance to activated it by default.
As far as I know there is somebody who has currently started to work on that algorithms. You can tested it with the debug flag "+d=tearing".

For further information about the transformation process you can also activate the following debug flags:
dumpdaelow -   Dumps the equation system before the transformation.
dumpindxdae - Dumps the equation system after index reduction and optimisation.
backenddaeinfo - Dumps more summerized information about the model.

with omc +help=debug you can see all available debug flags.

so long.

Re: Is BLT-transformation default in OM?

Oh thanks Willi.

Could you please give an example where these options are set. Is it possible to activate them from the GUI?



Re: Is BLT-transformation default in OM?

As far as I can tell you can't use them from OMEdit, or even not in OMShell.
Use the omc in a terminal:


omc +help
omc +help=debug
omc  +s <> +d=dumpindxdae,backenddaeinfo
omc  +s <> +d=tearing

so long.

Re: Is BLT-transformation default in OM?



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