https://www.intel.com/content/www/us/en/docs/mpi-library/developer-reference-windows/2021-9/mpiexec-hydra.html
mpiexec.hydra
This Developer Reference provides you with the complete reference for the Intel(R) MPI Library.
hydra
https://www.ks.uiuc.edu/Research/namd/mailing_list/namd-l.2018-2019/1002.html
namd-l: multi-node mpiexec issue
namdlnodeissue