Can't run tutorial in notebook

[matham]

Objective of issue: Tutorial crashes

Lava version:

• current main (dec 6)
• 0.3.0 (feature release)
• 0.2.1 (bug fixes)
• 0.2.0 (current version)
• 0.1.2

I'm submitting a ...

• bug report
• feature request
• documentation request

I'm simply running through the cells of the tutorial one after the other from the GUI for tutorial02_processes and it freezes and the logs show the following error:

$ jupyter notebook
[I 14:59:09.234 NotebookApp] Serving notebooks from local directory: G:\Python\lava\lava
[I 14:59:09.234 NotebookApp] Jupyter Notebook 6.4.6 is running at:
[I 14:59:09.234 NotebookApp] http://localhost:8888/
[I 14:59:09.234 NotebookApp]  or http://127.0.0.1:8888/?token
[I 14:59:09.234 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[C 14:59:09.303 NotebookApp]

    To access the notebook, open this file in a browser:
        file:///C:/Users/Matthew%20Einhorn/AppData/Roaming/jupyter/runtime/nbserver-17496-open.html
    Or copy and paste one of these URLs:
        http://localhost:8888/?token
     or http://127.0.0.1:8888/?token
[W 14:59:34.725 NotebookApp] Notebook tutorials/in_depth/tutorial02_processes.ipynb is not trusted
[I 14:59:36.725 NotebookApp] Kernel started: dc72d164-3797-45f8-b4b4-ba468a763ba4, name: python3
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "C:\Users\Matthew Einhorn\AppData\Local\Programs\Python\Python39\lib\multiprocessing\spawn.py", line 116, in spawn_main
    exitcode = _main(fd, parent_sentinel)
  File "C:\Users\Matthew Einhorn\AppData\Local\Programs\Python\Python39\lib\multiprocessing\spawn.py", line 126, in _main
    self = reduction.pickle.load(from_parent)
AttributeError: Can't get attribute 'PyLifModel' on <module '__main__' (built-in)>
[I 15:01:36.642 NotebookApp] Saving file at /tutorials/in_depth/tutorial02_processes.ipynb

[PhilippPlank]

I assume your OS is MS Windows? This is the same issue as described here #95 correct?
We are looking into this.

[matham]

Yes, it is! Didn't see it :(

[PhilippPlank]

No worries, I just wanted to know if it is the same issue or a new one ;)
We will work on fixing it in the next weeks, until then a workaround would be to export the jupyter notebook into a python script via File -> Download as -> Python (.py) and run the python script instead of the notebook.

[awintel]

You do not even have to go that far if you prefer to mostly work in jupyter for your own example. You can also just put Process and ProcessModel definitions into a separate file and import it into jupyter from there.

This is related to a Python multiprocessing issue on Windows that we are currently using in the background.

This will likely not get resolved in 2021 anymore due to the approaching holiday season but who knows...

[Synchronicity89]

In Windows 10, using Visual Studio Community to run python files, and Visual Studio Code to run Jupyter notebook files, I have had varied results with tutorials. Sometimes I have to export the tutorial and then it runs OK in VSComm. Other times it runs better in the Jupyter notebook in Code. For example, after fixing this line in tutorials\in_depth\tutorial04_execution:

# runtime = Runtime(run_cond=run_condition, exe=executable)
runtime = Runtime(executable, ActorType.MultiProcessing)

It no longer crashes but runs better in Jupyter notebook

[PhilippPlank]

I will close this issue to remove duplicates. Please discuss further in #247. The issue is not solved yet.