Compile Platform Binary for Darwin

[sergiochavezlazo96]

Hello! First of all, thank you for working on this project, is very helpful.

I am trying to replicate the bouncingBall example but I am not able to compile the code to Darwin. I am aware this was an issue with the old pythonfmu but they mention they solved the problem with posterior PR. However, that limitation seems to remain. Do you know how to overcome this limitation ?

[StephenSmith25]

Hey. Sorry I am not 100% clear what the question is here. I'm not an OSX user so this might be hard for me to debug.

The screenshot seems to be from fmpy? Can it not run the FMU or is it the lack of compilation option that's the issue. What happens if you use FMU v2 exported from PythonFMU? What is the expected behavior here?

[sergiochavezlazo96]

Hello. Sorry, the issue was not clear enough.

I am an OSX user andI am trying to use pythonFMU to create an fmu. Currently, I am trying to replicate to BouncingBall example you provided in this project.

When I run pythonfmu3 build -f bouncingBall.py I am successfully creating the .fmu folder. I am trying to use it through fmpy (the screenshot comes from its gui but I also tried with a Jupyter notebook). When I try to run it I am getting the following message:

Exception: The FMU cannot be simulated on the current platform (darwin64).

The fmpy GUI also doesn't have the Compile platform binary activated for Darwin.

The expected behaviour is to be able to use the generated .fmu in pythonfmu through the package fmpy given that I am OSX user.

Hope is more clear. Thank you so much for the reply.

[StephenSmith25]

Okay. Thanks for the clarification.

The exception is quite generic, but I feel it relates to NTNU-IHB/PythonFMU#187. Unfortunately the set up at the moment links the FMU to libpython. This is an issue if you are going to use the FMU in a python environment, e.g fmpy and it will lead to a crash on osx. If you incorporate those changes and build this project you should be able to use it on osx. To build,

1. cd pythonfmu3/pythonfmu-export

2. build the project, build scripts in the folder can be used

3. now cd into the root and do pip install ., or pip install -e .

The FMU should now no longer link to python, so should at least run on osx in fmpy. As for the compilation options, I have no idea why they are disabled. Let me know if you run into any issues here, or need any further instructions. Unfortunately, I am not an OSX user, so I've really been ignoring that OS up until now.

Personally, I'm in two minds of whether to incorporate these changes into the project permanently. I think it's most likely necessary, but if you're using the FMU in a non python tool then having the link to libpython is necessary to resolve dependencies correctly. But I need to think about this more...

[sergiochavezlazo96]

Hi @StephenSmith25, thank you so much. I am going to try what you said and let you know how it goes. I would also like to know why pythonfmu or pythonfmu3 does not support model exchange. Is it because it too different to cosimulation or is just not relevant to your purposes? I am asking this because I am planning to write a function or package that does support the creation FMU for model exchange and I was thinking to use pythonfmu3 as a base line?
Thank you once again for your help and continuing this amazing project.

[StephenSmith25]

Hey. I don't know if there is a particular reason why model exchange is not supported in PythonFMU. In my case, with pythonfmu3, I just didn't have a use for it as I am working in the area of cosimulation. I don't think it would be that difficult to extend the project to support Model exchange, as most the code already exists on the c++ side.