Moving to openmpi on ubuntu 24.04

[bsrunnels]

If you are running ubuntu 24.04, you must use openmpi instead of mpich, otherwise alamo will not run properly. If you are starting on a clean system, you can just follow the instructions in the documentation.

If you are modifying your current system, follow these steps:

1. Ensure that you have merged the latest development into your branch

    git checkout development 
    git pull
    git checkout my-branch
    git merge development
    # resolve conflicts if any
    git commit
    git push
   

2. Install openmpi

    sudo apt install libopenmpi-dev
   

3. Ensure that your system uses openmpi instead of mpich with

    sudo update-alternatives --config mpi
    sudo update-alternatives --config mpirun
   

4. Purge all old alamo and amrex compilations with

    make realclean
   

5. Reconfigure and build. In the output of your configure script you should see

    mpi implementation     openmpi
   

   (if you do not, check steps 2-3)

(Pursuant to #127)