[gmx-users] Replica Exchange MD Errors

[Robert Johnson]

Hello everyone,
I am trying to run some benchmakrs on a replica exchange simulation. I
have several .tpr files: topol0.tpr, topol1.tpr, topol2.tpr, up to
topol7.tpr. I would like the calculation to proceed all on the same
node (for benchmarking and debugging reasons and so I don't have to
wait in a queue). However, I am having problems launching the job.
Here are the commands I've tried along with the corresponding error
message:

mpirun -np 1 mdrun_mpi -replex 160 -s topol
ERROR: Can not open file topol.tpr

mpirun -np 1 mdrun_mpi -replex 160 -s topol*
ERROR: Nothing to exchange with only one replica

I've tried other combinations and included the -multi flag, but all
have given one of these error messages. Any suggestions?
Thanks,
Bob Johnson