python

Virtual Environment

• Rationale and the official solution: https://docs.python.org/3/tutorial/venv.html
• Conda-based:
  • install miniforge instead of miniconda
  • run conda init $((basename $SHELL)) to create a conda shell function in ~/.?shrc
  • run conda config --set auto_activate_base false to avoid turning your shell into the base environment automatically.
  • run conda create -n g4 geant4 to create an virtual environment called g4 with package geant4 installed in it. (NOTE: this doesn’t work for Windows)
  • run conda activate g4 to get into the g4 virtual environment
    • Geant4 datasets installed through Conda do not have G4 in front of their folder names. This lets geant4-config --check-datasets report errors.
    • use cmake -DCMAKE_PREFIX_PATH=/path/to/miniforge/base/folder/ -B build to let [cmake] use miniforge-based libraries.
    • HDF5 installed by Conda is not thread safe, while geant4 installed by Conda is multithread enabled. This causes trouble to compile geant4 applications.
  • run conda deactivate to quit the virtual environment
  • way to uninstall:
    • conda init --reverse $((basename $SHELL)) to remove conda function in ~/.?shrc
    • brew remove miniforge on MacOS or simply delete folder /path/to/miniforge on Linux
• Docker-based.

python in cygwin

python is provided in cygwin. One can follow this question in stackoverfow to install python packages.

Libraries

SimpleHTTPServer

The following command will serve the contents of the directory where the command is executed at port 8080:

python -m SimpleHTTPServer 8080

By default the server is running at port 8000. No root access is required to run this command.

Web socket

It is used to establish a permanent connection between the web server and a client through which the server can push data to the client. There is no need to have an update loop on the client side.

Kill script with ctrl-C when there is thread in it

https://stackoverflow.com/questions/11815947/cannot-kill-python-script-with-ctrl-c

Show modules available

In python:

help('modules')

In shell:

pydoc3 modules

plotting

xkcd style

https://en.wikipedia.org/wiki/Xkcd https://matplotlib.org/api/_as_gen/matplotlib.pyplot.xkcd.html