Installation procedure on MacOSX

Install Python3:

To install pyFAI on an Apple computer you will need a scientific Python3 stack. MacOSX provides by default Python2.7, you will need to install a recent version of Python3 (3.7 at least). Those distribution are available as dmg images from: Python.org

After downloading, move the app into the Applications folder.

Using a virtual environment:

It is not adviced to use pip together with sudo. Always use a virtual environment !

python3 -m venv pyfai
source pyfai/bin/activate
pip install pyFAI[full]

If you get an error about the local “UTF-8”, try to:

export LC_ALL=C

Before the installation.

Installation from sources

Get the sources from Github:

python3 -m venv pyfai
source pyfai/bin/activate
pip install build
wget https://github.com/silx-kit/pyFAI/archive/main.zip
unzip main.zip
cd pyFAI-main
pip install -r requirements.txt
pip install . --upgrade

About OpenMP

OpenMP is a way to write multi-threaded code, running on multiple cores simultaneously. PyFAI makes heavy use of OpenMP, but there is an issue with recent versions of MacOSX (>v10.6) where the default compiler of Apple, Xcode, dropped the support for OpenMP.

There are two ways to compile pyFAI on MacOSX:

Using Xcode which desctivates OpenMP
Using another compiler which supports OpenMP

Using Xcode

To build pyFAI from sources, a C-compiler is needed. On an Apple computer, the default compiler is Xcode, and it is available for free on the AppStore. The absence of OpenMP is mitigated on Apple computer by the support of OpenCL which provied parallel intgeration.

Using gcc or clang

If you want to keep the OpenMP feature (which makes the processing slightly faster), the alternative is to install another compiler like gcc or clang on your Apple computer and define the environment variable CC.