Getting ArrayFire source code is as simple as running the following command.

git clone --recursive https://github.com/arrayfire/arrayfire.git

If you are cloning any version prior to 3.8.0 then, please make sure you clone along with --recursive git option so that all necessary submodules are also fetch during clone.

git clone --recursive https://github.com/arrayfire/arrayfire.git -b v3.8.0

In case you forgot to do it, submodules may also be pulled by running the following from the ArrayFire repository:

git submodule init
git submodule update