Hi @CRquantum
I can answer a few of your questions:
what is the most easy way to use gfortran + mpi for M1 chip Mac?
A lot of Apple computer users (both Apple M1 chip and Intel x86 chip) use Homebrew or MacPorts to install and manage packages from the command line on their macOS computers.
I have tried both, and currently use Homebrew. Once setup, you can install gfortran with the command: brew install gfortran. I have not used mpich but a quick search with brew info mpich does show it exists at version: stable 4.0.1.
More details here: Homebrew ‘mpich’
The command shown in you message using apt is to install the packages under Linux, where apt is package manager (ie similar to Homebrew) - but used on Linux distributions such as Debian and Ubuntu, plus others. The equivalent command using Homebrew would be:
brew install gfortran mpich
NB: the use of sudo is not required for Homebrew.
does that gfortran and mpi run properly on M1 chip?
I use gfortran on my M1 based Apple computers and it works well. The currently installed version via Homebrew is:
GNU Fortran (Homebrew GCC 11.2.0_3) 11.2.0
There are other approaches available as well - but the above is probably the most common for macOS computers.
Hopefully someone else can help with your question about mpi running correctly 