Numextension¶

Numextension is a Python module containing a set of functions Leginon needs to operate on Numpy arrays. Since it is implemented in C rather than in pure Python, the module must be compliled before using. You can avoid compiling yourself by using one of the provided Windows installers for commonly used versions of Python and Numpy. For non-standard or newer versions of Python/Numpy, use the instructions below for doing your own compile.

Pre-compiled Windows Installers¶

• numextension-git.win-amd64-py3.8.exe
• numextension-git.win-amd64-py3.9.exe

Compiling Numextension on Windows¶

Install Build Tools¶

Windows versions of Python and Numpy are developed using Microsoft Visual Studio. Extension modules written in C should also be compiled with VS. Luckily you do not have to install a full version of Visual Studio. Compiling a Python extension only requires a minimal set of command line build tools. These tools are documented here:

https://docs.microsoft.com/en-us/cpp/build/building-on-the-command-line?view=msvc-160

and can be downloaded from here:

https://visualstudio.microsoft.com/downloads/#build-tools-for-visual-studio-2019

Install Python and Numpy you want to compile numextension for¶

• You may install multiple versions of python, then use the "py" launcher to select which one to use
• Download and install Python: https://www.python.org/downloads/windows/
  • In the optional installation features, it is recommended to select installing "py launcher" so you can easily select which python version to run on the command line
• Use pip on the command line to install numpy, use specific pip for version of python you are installing in (eg. pip3.8, pip3.9, etc)
  • As of 2020-11-29, there is a bug in Win 10 (update 2004) that prevents some versions of numpy to work correctly. The bug and workaround is detailed here: https://developercommunity.visualstudio.com/content/problem/1207405/fmod-after-an-update-to-windows-2004-is-causing-a.html
  • Workaround is to install older version 1.19.3 version of numpy instead of 1.19.4:
    • pip3.8 uninstall numpy (if you already have numpy installed)
    • pip3.8 install numpy==1.19.3

Compile numextension in a VS native tools command prompt:¶

• Search and launch this from start menu: "x64 Native Tools Command Prompt for VS 2019"
• cd to the numextension directory
• compile and build a windows installer for your specific Python version.
  • py -3.8 setup.py bdist_wininst
• The new windows installer will be found in the numextension/dist folder