MDAnalysis¶

OpenMP on macOS¶

Apple's Clang compiler does not support OpenMP, and g++ on macOS is an alias for clang++. Therefore, compiling a simple OpenMP program with g++ -fopenmp fails on macOS.

clang: error: unsupported option '-fopenmp'
clang: error: unsupported option '-fopenmp'

Simple OpenMP program

#include <omp.h>

int main(void) {
    omp_get_num_threads();
}

g++ on macOS is an alias for clang++.

OpenMP Support with GCC¶

In order to use OpenMP on macOS, one needs to install gcc, for example via Homebrew.

brew install gcc

MDAnalysis can then be installed with OpenMP support as follows:

CC=gcc-11 CXX=g++-11 pip install -e package

Disabling OpenMP Support¶

OpenMP support can be explicitly disabled with

MDA_USE_OPENMP=FALSE CC=gcc-11 CXX=g++-11 pip install -e package