Multiple Walker simulations without MPI

GROMACS version: 2019.4
GROMACS modification: Yes, PLUMED

Hi all,

The PLUMED Belfast tutorial for replica-exchange and multiple walker simulations (PLUMED: Belfast tutorial: Replica exchange II and Multiple walkers) notes that multiple walker simulations can be run independently without MPI, using the filesystem to share the biasing potential. Does this require any different directory structure to the -multi method? And how would the mdrun call look like?

My guess is from the original:

mpirun -np 4 gmx_mpi mdrun -s topol -plumed plumed -multi 4 >& log &


gmx mdrun -s topol0.tpr -plumed plumed.dat
gmx mdrun -s topol1.tpr -plumed plumed.dat
gmx mdrun -s topol2.tpr -plumed plumed.dat
gmx mdrun -s topol3.tpr -plumed plumed.dat

Is this correct?