MacOS has the compiler “gfortran” and the libraries “LAPACK” and “BLAS” installed already as system libraries. Important is to install “Xcode” from the Appstore. (Sign the license after opening it from the application folder.) Then install the “Command-Line tools” of Xcode. (Check the web for installation instructions).

I am installing Linux programs using homebrew. If you do not have it already, follow the installation instruction on its web page. Then install the following libraries.

brew install fftw  --with-fortran
brew install openmpi
brew install grace

1. Unpack the PAW distribution into a directory, which I will name PAWDIR in the following.
2. add the directory PAWDIR/bin/osx_gfortran_accellerate to your PATH variable in your ~/.profile
3. Create a file ''parms.osx_gfortran_accelerate'' in PAWDIR
4. Check the values of the parameters FFTDIR, FFTHEADER, MPIDIR, and MPIDIR in parms.osx_gfortran_accelerate. Most likely you will need to adjust the version numbers.
5. execute in PAWDIR

        autoconf
        configure --with-parmfile=parms.osx_gfortran_accelerate
        make all 

After the configure command you should get some information that ends with done!—configuration completed successfully!. If not inspect the error messages. The make command may take a very long time if you set up the code for the first time.

1. Code sign: When you try to remotely execute unsigned code under macos, it will ask you for permission. This is painful when you run parallel code. Therefore it is advisable to sign the parallel executables. This is a fairly complicated procedure, which you need to look up.
2. Increase the stack size and the core-dump size

<code>

    ulimit -s 65532 
    ulimit -c unlimited 
  </code