ModuleNotFoundError: No module named 'PyNEC'

[jdh4]

I am on RHEL7. The shared library buids successfully but when I try to do "from PyNEC import *" it produces the error: ModuleNotFoundError: No module named 'PyNEC'

My PYTHONPATH includes $HOME/.local/lib/python3.8/site-packages as confirmed by print(sys.path).

The contents of that directory is:

easy-install.pth PyNEC-1.7.3.6-py3.8-linux-x86_64.egg

There is no directory called PyNEC containing an init.py file.

Here are the contents of the one directory:

$ ls PyNEC-1.7.3.6-py3.8-linux-x86_64.egg/ EGG-INFO examples pycache _PyNEC.cpython-38-x86_64-linux-gnu.so _PyNEC.py

[afiskon]

I have the same issue on MacOS Catalina 10.15.7. Python version is 3.9.1. It used to work last time I tried PyNEC in April 2020.

[afiskon]

As a workaround the previous version can be installed:

pip3 install PyNEC==1.7.3.4

Something was broken between releases 1.7.3.4 (Aug 2019) and 1.7.3.6 (May 2020)

[glenndk]

I have the same issue on MacOS 10.14.6:

$ pip freeze cycler==0.10.0 kiwisolver==1.3.1 matplotlib==3.4.1 necpp==1.7.3.5 numpy==1.20.2 Pillow==8.2.0 PyNEC==1.7.3.6 pyparsing==2.4.7 python-dateutil==2.8.1 scipy==1.6.2 six==1.15.0 $ python -V Python 3.9.4 $

Works after downgrade (but got an error "RuntimeError: SYMMETRY ERROR - NROW: 1929734915 NCOL: 1778416642" - might be my own fault [2021-may-08: Was my fault. PyNEC works in this environment]): $ pip freeze cycler==0.10.0 kiwisolver==1.3.1 matplotlib==3.4.1 necpp==1.7.3.5 numpy==1.20.2 Pillow==8.2.0 PyNEC==1.7.3.4 pyparsing==2.4.7 python-dateutil==2.8.1 scipy==1.6.3 six==1.15.0 $ python -V Python 3.9.4 $

[afiskon]

@glenndk try requirements.txt from this project https://github.com/afiskon/pynec-examples Worked for me.

[glenndk]

@afiskon Thanks for your comment. It was a fault in my test program. PyNEC==1.7.3.4 works in this environment:

$ pip freeze cycler==0.10.0 kiwisolver==1.3.1 matplotlib==3.4.1 necpp==1.7.3.5 numpy==1.20.2 Pillow==8.2.0 PyNEC==1.7.3.4 pyparsing==2.4.7 python-dateutil==2.8.1 scipy==1.6.3 six==1.15.0 $ python -V Python 3.9.4 $

[Nothing-Burger-Left-Pizza]

Similar problem here. "No module named 'PyNEC'". :-(

[Benitoite]

$ pydoc3 modules

Please wait a moment while I gather a list of all available modules...

_PyNEC  

>>> import _PyNEC
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: dynamic module does not define module export function (PyInit__PyNEC)

[daniel-ayers]

This is because (on my system at least) the name of the swig binary has changed from swig3.0 to just swig - see build.sh https://github.com/tmolteno/python-necpp/blob/master/PyNEC/build.sh#L17 .

If you look carefully at the output of the build process, swig isn't running at all. Making the above change fixed it for me.

[Benitoite]

@daniel-ayers Oh good catch. The module specified installing building with version 3, whereas swig is currently at version 4.

PR https://github.com/tmolteno/python-necpp/pull/26 generated.

[aeropung]

I know this is off-topic, but is PyNEC still being actively developed? If so, is there somewhere that provides documentation of the pl_card from the bottom of this page?

[daniel-ayers]

... is there somewhere that provides documentation of the pl_card ...

PyNEC is a Python wrapper around a C++ library that implements a very old (c. 1980) input & output format. To understand the PL card refer to the documentation of the original library - see https://github.com/tmolteno/python-necpp/issues/22#issuecomment-1469618534 .

[rezamarzban]

As a workaround the previous version can be installed:

pip3 install PyNEC==1.7.3.4

Something was broken between releases 1.7.3.4 (Aug 2019) and 1.7.3.6 (May 2020)

Solved the problem ...