OpenMP Support

The setup.py script tests to see of OpenMP is available during installation. Unit tests executed by continuous integration (Linux only, no macOS) currently do not enforce successful OpenMP discovery, but if OpenMP is found, tests are executed. You can check the build manifests and recent logs for more detailed information about OpenMP being tested by CI.

Three platforms have been manually tested for OpenMP support:

  • Arch Linux: system python (3.7.2) and GCC (8.2).
  • Debian Buster: system python3 (3.7.2) with GCC 8.3 and libgomp1 installed.
  • macOS 10.14: Homebrew python3 (3.7.2) with libomp installed from Homebrew (Apple LLVM version 10.0.0). Also Anaconda python3 (3.6.8 and 3.7.2) and python2 (2.7.15) distributions with libomp installed from Homebrew (you’ll likely need to remove the extra libiomp5.dylib from the Anaconda environment lib folder or conda install nomkl, see here).

To check if OpenMP was detected and used while compiling the extension module pygram11._core, try the following:

>>> import pygram11
>>> pygram11.OPENMP
True

Needless to say, if you see False OpenMP acceleration isn’t available.

The histogramming functions use a named argument for requesting OpenMP usage. If pygram11.OPENMP is False then the argument is ignored by the C++ code.