We first need to define an environment variable for the root directory of COMPAS in your shell start-up file for COMPAS to run properly. For example, if you use bash as your shell, open ~/.bashrc with a text editor and put in the following:


where ~/codes should be replaced with the path to the directory where you cloned the COMPAS repository. For this to take effect, either restart your bash session or run:

source ~/.bashrc

If your shell is zsh (which is the default of macOS 10.15), set the environment variable as above in ~/.zshrc instead of ~/.bashrc. If your shell is csh, set the environment variable in ~/.cshrc using:


Now go to the COMPAS source code directory:


In this directory you will find the file Makefile, which you need to edit to point to your gsl, boost, and hdf5 include files and libraries.

If you installed the packages with Homebrew, the package files are likely to be found in /usr/local/opt (in directories gsl, boost, and hdf5 respectively), but if they are not found there you will need to use Homebrew to locate the files:

$ brew info boost
boost: stable 1.72.0 (bottled), HEAD
Collection of portable C++ source libraries
/usr/local/Cellar/boost/1.72.0 (14,466 files, 648.5MB) *

Copy the path, which in this case is /usr/local/Cellar/boost/1.72.0, and add it to the appropriate lines of the Makefile:

BOOSTINCDIR = /usr/local/Cellar/boost/1.72.0/include
BOOSTLIBDIR = /usr/local/Cellar/boost/1.72.0/lib

To build the COMPAS executable (compile and link) type:

make -f Makefile

The build process will run much faster if multiple processors/cores are available. To build the COMPAS executable using (e.g.) 4 cores, type:

make -j 4 -f Makefile

Note that both make commands shown above will conduct incremental builds: they will only compile source files that have changed. To ensure a clean build in which all source files are compiled, type:

make clean
make -j 4 -f Makefile

The clean option instructs make to remove all existing object files (.o), and the COMPAS executable. A subsequent make is then forced to compile all source files and link the resultant object files (and external libraries) into a new executable.

The executable can be tested with, e.g.,


which will display the code version.

See Building COMPAS locally for a detailed description of Makefile functionality.

A note for Mac users:

If you are using MacOS and running into linking issues with the boost libraries, try:

make clean
make CPP=clang++ -j$(sysctl -n hw.ncpu)

In some Mac installations, the GNU C++ compiler is not installed how we might expect, so trying to compile and link with clang++ might help.