running multiple partitions on a single processor

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1

Hi all,

In the documentation for neb it states: “Note that if you have MPI installed, you can run a multi-replica simulation with more replicas (partitions) than you have physical processors, e.g you can run a 10-replica simulation on just one or two processors.”

However, I cannot find an example in the doc or on the list on how to run multiple partitions on a single processor. Can someone please give me the appropriate mpirun command with the correct -partition option in order to accomplish this?

Thanks for your time,

-CBL

2

Suppose your computer has only 1 physical processor. If you have an MPI installation, you can still do:

mpirun -np 4 lmp_linux -partition 4x1 -in in.neb.hop1

It’s just that now all four MPI processes will be sharing the one processor. At best, it will run 4 times as slow as running on four cores with good memory bandwidth. But you will still get the same answer at the end.

Aidan

3

Aidan,

Thanks for your reply, that was easy enough.

-CBL