Tutorial Python Code Error

[bytetec]

Hi everyone

I tried the pure python tutorial code but it fails with "list index out of range" error.

https://docs.flamegpu.com/tutorial/index.html#tutorial-creating-the-circles-model

Has anybody an idea how to fix this?
Thx in advance for helping.

[Robadob]

Hi,

I'm not too familiar with the Python native API (It was developed by @mondus).

I just built pyflamegpu from master (with Python 3.9) on my local machine and tried to run the full tutorial source (from the end of the page).

There was an error, addRoot() at line 89 should be addExecutionRoot() (I'll correct this ASAP), but after fixing that the tutorial ran without an exception being thrown.

It's possible you've made a mistake in following the tutorial. Based on the specific code where the error is occurring, I would assume that method being passed to pyflamegpu.codegen.translate() is incorrectly defined.

Could you possibly share your code in a gist so that I can investigate further (and perhaps add a clearer error to the codegen function).

[bytetec]

Hi Robadob
Code is an 1:1 copy from the tutorial page plus the addRoot() correction.
I'm using Python 3.11 could that be an issue? Otherwise I think it is something with the c++ setup, I'm not very familiar with that.

This is all I get.

[bytetec]

Thank you, I'm not in a hurry :-)

[Robadob]

Built pyflamegpu from the bugfix_pynative_2023_07_05 branch (this just fixes the pynative translation bug that I noticed whilst investigating your first post) with Python 3.11.4 installed via miniconda, and it runs fine for me.

Could you perhaps download this copy of the tutorial, the same version I'm running and check whether that works? My current best guess is that you've got some unusual/subtle difference in your copy somehow.

If that fails, next step would be having you run it through a standalone copy of codegen.py so we can actually log some information to catch where the difference is coming from.

[Robadob]

I also noticed in the second screenshot you posted, you're use PyCharm (and it's included in the callstack of the error). It's possible PyCharm is running the code weirdly to enable debugging and this interfering with how codegen grabs the code. Are you able to try and run the tutorial outside of pycharm? If that's confirmed to be the problem we can look into it and find a resolution.

[Robadob]

Ok I've thought about this overnight.

I'm fairly certain PyCharm's PyDev debugger's exec(compile(contents+"\n", file, 'exec'), glob, loc) is to blame. Somehow, it's breaking codegen's detection of the function.

I've tried moving the tutorial inside a module, but that doesn't break it. So I'll need to find time to install this module to debug this further.

A temporary workaround for yourself would be to instead pass the agent functions as strings, bypassing the detection that is failing.

The original fn

@pyflamegpu.agent_function
def output_message(message_in: pyflamegpu.MessageNone, message_out: pyflamegpu.MessageSpatial2D):
    message_out.setVariableUInt("id", pyflamegpu.getID())
    message_out.setLocation(
        pyflamegpu.getVariableFloat("x"),
        pyflamegpu.getVariableFloat("y"))
    return pyflamegpu.ALIVE
    
output_func_translated = pyflamegpu.codegen.translate(output_message)

Simply becomes:

output_message_str = """
@pyflamegpu.agent_function
def output_message(message_in: pyflamegpu.MessageNone, message_out: pyflamegpu.MessageSpatial2D):
    message_out.setVariableUInt("id", pyflamegpu.getID())
    message_out.setLocation(
        pyflamegpu.getVariableFloat("x"),
        pyflamegpu.getVariableFloat("y"))
    return pyflamegpu.ALIVE
    
output_func_translated = pyflamegpu.codegen.translate(output_message_str)
"""

I've created a new issue, #1078, to track this as I'm not confident I'll find a resolution quickly.

[bytetec]

yes, without PyCharm it works. Also the workaround works.

I'm pretty sure that in the 2022 version of PyCharm hadn't this error.
Thanks for opening the issue and specially your help.

[Robadob]

Which version of PyCharm are you using? I'll try and reproduce this if I get time this afternoon.

[bytetec]

PyCharm 2023.1.2 (Professional Edition)
Build #PY-231.9011.38, built on May 16, 2023

[Robadob]

I still can't reproduce this 😢

Both Debug and Run work for me in the latest PyCharm (I couldn't spot a download old version link) and Python 3.11

PyCharm 2023.1.3 (Professional Edition)
Build #PY-231.9161.41, built on June 20, 2023

This is all that prints to console in each case, it's visible that pydevd is being used.

Debug

C:\Users\Robert\miniconda3\envs\py311\python.exe "C:/Program Files/JetBrains/PyCharm 2023.1.3/plugins/python/helpers/pydev/pydevd.py" --multiprocess --qt-support=auto --client 127.0.0.1 --port 56357 --file C:\Users\Robert\PycharmProjects\pythonProject\main.py -s 100 
Connected to pydev debugger (build 231.9161.41)

Process finished with exit code 0

Release

C:\Users\Robert\miniconda3\envs\py311\python.exe C:\Users\Robert\PycharmProjects\pythonProject\main.py -s 100 

Process finished with exit code 0

Without being able to reproduce the unexpected behaviour, I doubt we can address it unless you want to assist by debugging it on your end.