# Installation of Python Fast Azimuthal Integration library¶

## Abstract¶

Installation procedure for all main operating systems

## Hardware requirement¶

PyFAI has been tested on various hardware: i386, x86_64, PPC64le, ARM. The main constrain may be the memory requirement: 2GB of memory is a minimal requirement to run the tests. The program may run with less but “MemoryError” are expected (appearing sometimes as segmentation faults). As a consequence, a 64-bits operating system with enough memory is strongly advised.

## Dependencies¶

PyFAI is a Python library which relies on the scientific stack (numpy, scipy, matplotlib)

• Python: version 3.5 or newer (version 2.7 and 3.4 were just dropped with 0.18)
• NumPy: version 1.12 or newer (version 1.8 was dropped with 0.18)
• SciPy: version 0.18 or newer (version 0.14 was dropped with 0.18)
• Matplotlib: verson 2.0 or newer (version 0.99 was dropped with 0.18)
• FabIO: version 0.5 or newer
• h5py (to access HDF5 files)
• silx (version 0.10 http://www.silx.org)

There are plenty of optional dependencies which will not prevent pyFAI from working by may impair performances or prevent tools from properly working:

• pyopencl (for GPU computing)
• fftw (for image analysis)
• PyQt5 or PyQt4 or PySide (for the graphical user interface)

## Build dependencies:¶

In addition to the run dependencies, pyFAI needs a C compiler to build extensions.

C files are generated from cython source and distributed. The distributed version correspond to OpenMP version. Non-OpenMP version needs to be built from cython source code (especially on MacOSX). If you want to generate your own C files, make sure your local Cython version is sufficiently recent (>0.20).

## Building procedure¶

python setup.py build


There are few specific options to setup.py:

• --no-cython: Prevent Cython (even if present) to re-generate the C source code. Use the one provided by the development team.
• --no-openmp: Recompiles the Cython code without OpenMP support (default under MacOSX).
• --openmp: Recompiles the Cython code with OpenMP support (Default under Windows and Linux).
• --with-testimages: build the source distribution including all test images. Download 200MB of test images to create a self consistent tar-ball.

## Test suites¶

PyFAI comes with a test suite to ensure all core functionalities are working as expected and numerical results are correct:

python setup.py build test


Nota: to run the test, an internet connection is needed as 200MB of test images need to be download. You may have to set the environment variable http_proxy and https_proxy according to the networking environment you are in. Specifically at ESRF, please phone the hotline at 24-24 to get those information.

## Environment variables¶

PyFAI can use a certain number of environment variable to modify its default behavior:

• PYFAI_OPENCL: set to “0” to disable the use of OpenCL
• PYFAI_DATA: path with gui, calibrant, …
• PYFAI_TESTIMAGES: path wit test images (if absent, they get downloaded from the internet)