Crash when calling Python via C++ plugin in EDEM (tested with built-in and local Python 3.8)

rorccccc

Dear EDEM Support Team,

I am currently developing a C++ plugin for EDEM and would like to call custom Python functions using the Python C API (e.g., PyImport_ImportModule, PyObject_CallObject, etc.).
These Python scripts work correctly in a standalone Python environment, and calling the Python modules from a standalone C++ application also works without issues.
If I call Py_Initialize() or PyEval_InitThreads() from the plugin, EDEM sometimes crashes with the message:(Fatal Python error: can't initialize sys standard streams).
I have already tried:
1. Using EDEM's built-in Python38.dll and python38.lib;

2. Using my locally installed official Python 3.8 interpreter;

3. Using GIL management;
However, both environments result in the same random crash, especially during the second call to Python.
My questions are:
1. Does EDEM internally initialize and manage a Python interpreter via Python C API?

2. Is it supported and safe to use the Python C API from within a plugin (e.g., Py_Initialize, PyGILState_Ensure)?(Particle Body Force)

3. If so, is there a recommended initialization order, thread management, or plugin calling procedure?

4. Is there a recommended way to safely interact with EDEM’s Python environment from a C++ plugin?
Any advice, recommended practices, or documentation references would be greatly appreciated.
Thank you very much for your support and assistance!

Renan

Hi,

Under 2025.0/1 we create a new python interpreter to handle each analyst script call.

It is completely unsupported to manage a separate interpreter from inside a plugin, and I can't speak to what instability that might introduce. I suspect a large amount except in the most basic single-core cpu solver deck.

In the simplest cases (eg only used in the plugin starting method), in theory the usual Py_SetPythonHome, Py_Initialize, import/call/run sequence might be viable - but this isn't advised. Our GIL management is implicit in 2025 and so shouldn't interfere as it doesn't occur at solvetime

To be attempted I suspect setPythonHome must be loaded with the version of python shipped with edem, something like EDEM-Install/../common/python/python3.8/win64/

We believe that different options/versions will cause instability, so the safest attempt is to use the shipped version.

 The error 'can't initialize sys standard streams' can be caused by a lack of physical terminal to display the streams, this might be resolved by opening the edem console via view > toggle display commandline

At the moment we have no plans to enable python integration directly via the physics chain

Best regards,

Renan