Hi Lana I’m a Open MPI newbie too, but I managed to build Open MPI 4.0.4 quite easily on Ubuntu 20.04 just following the instructions in README/INSTALL in the top level source directory, namely:
mkdir build cd build ../configure CFLAGS=“-O3” # My CFLAGS make all sudo make all sudo make install It just worked. My small cluster happily runs Open MPI over TCP/1GB Ethernet. The make install step installed everything into /usr/local. I did forget to ldconfig initially, which confused me. Other than that it just worked. John
