Fortran installation in Mac OS (Intel)
For Mac OS Intel, we recommend to use homebrew. Trying to install gfortran (or gcc) from source can be complicated, and setup-related errors can be easily introduced.
For a safe installation, start executing in your terminal:
brew update
brew upgrade
brew doctor
The command brew doctor may show a list of fixes. We recommend to go through this list before moving on to the next step.
Finally, the fortran compiler can be installed by running in the terminal:
brew install gcc