Useful links:

Amber supports Apple's macOS. The instructions below are for installing Amber's prerequisites natively, i.e., without using a package management system. These systems can simplify the installation of the prerequisites but must be installed themselves.

Install XCode: Xcode contains Apple's development tools. To check whether you have it, run the following command in a terminal:

xcode-select -v

If you do not get a response containing the word version then install XCode. You can download it from the Mac App Store (just search for "xcode"). After installing XCode, you need to agree to the license. So run the following command in a terminal:

sudo xcodebuild -license

Then, read through the license (or type q to skip through it), and type "agree" when prompted. After this, you need to install the command-line tools. Running the following command in the terminal installs the command-line tools:

xcode-select --install

Install XQuartz: Starting with OS X 10.8, Apple stopped including X11 with their OS. Instead, you have to get the XQuartz program. To check whether you already have it, look in the Utilities folder in Applications. You can download it here.

Install gfortran: You will need a Fortran compiler. Apple doesn't supply one, but to check whether you have gfortran, run the following command in a terminal:

gfortran -v

If you do not get a response containing the word version then install gfortran. Get it for your macOS version here. Note: gfortran 11.2.0 was used to beta test Amber 22; using a version substantially newer might cause problems during the compilation of Amber.

Install cmake: Amber now builds with the cmake program, which you can get from cmake.org/download/. You will need to put this program in your PATH as well:

export PATH=/Applications/CMake.app/Contents/bin:$PATH

To check whether you have it installed and in your PATH, run the following command in a terminal:

cmake --version

You should get a response containing the word version.

Install Amber: Now you are ready to proceed with the installation instructions in the Amber manual. Briefly, go to the amber22_src/build folder, and edit and run the run_cmake script.