MacOS CMake Installation with Homebrew

Since the introduction of the CMake build system for Octopus, it is also possible to use this on MacOS. Here we give the instructions, using Homebrew. MacPorts might work, but is untested and currently unsupported.

Preparing the homebrew environment

Installing homebrew

You can install homebrew by following the instructions on HomeBrew.

We recommend adding the following line to your .zprofile:

eval "$(/opt/homebrew/bin/brew shellenv)"

Otherwise, you need to execute this command before you can use any brew-installed packages.

Installing required packages

For a CMake installation of Octopus, you need a number of packages on your system. First, you need to install CMake itself, as well as the compiler, the build system and pkg-config. You can do this with

brew install cmake ninja pkg-config gcc@13

Octopus has some required dependencies, some of which can be automatically installed by CMake but a few need to be installed with brew. These are fftw, gsl and for parallel builds also metis. They can be installed with:

brew install fftw openblas metis
brew install --cc=gcc13 open-mpi
brew install --cc=gcc13 gsl

Note that we **do not** install `libxc` from brew. While this works with sequential builds, MPI builds have a problem, which requires to build `libxc` itself with `CMake`

Configuring and compiling with CMake

With this environment in place, you can configure Octopus simply by

cmake --preset mac-brew-gcc13 --install-prefix=<dir>

This configures a serial build of Octopus. If you want to enable MPI, you need to add the option


to the above command.

This command will download `libxc` and configure it with default values, which disables the 3rd order kernels. These are needed for a subset of Octopus features, such as some Sternheimer or Casida calculations. In case you do need these kernels, add `-DLIBXC_DISABLE_KXC=OFF` to the command line.

If you want to check the result of the configuration, you can inspect the file `cmake_build_macos/CMakeCache.txt`, which contains more details on installed packages, etc.

You can now compile the code using:

cmake --build --preset mac-brew-gcc13

The first compilation might take a while, as it also will compile remaining dependencies, such as libxc.

Testing the compiled code

To test the code, you can invoke:

ctest --preset mac-brew-gcc13

This will run a subset of the tests, which should complete in about 20 minutes (depending on your machine).

At the time of writing, it is expected that some tests will fail, as the results of some sensitive tests fall slightly outside the set tolerances.