MPICH, depending on the device, supports MPMD programs. However, the mpirun script currently does not support MPMD programs. For the ch_p4 device, the user must create a mpichman-chp4/node14.htm\#Node21 procgroup file and invoke the program that will have rank zero in MPI_COMM_WORLD with the command-line option -p4pg filename. See the Installation and User's Guide for more information.