LAMMPS output abbreviations.

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1

Hello,

I had a question about the meaning of certain output from a LAMMPS simulation.
After the simulation has finished running, LAMMPS outputs the number of ‘procs’ on which the simulation was run (for example, I have a simulation that has output “Loop time of 52.5691 on 20 procs (20 MPI x 1 OpenMP) for 10000 steps with 19449 atoms”)

What are these ‘procs’? Is this simply the number of processors, or something else?

Thank you

Casey Hansen
casey.e.hansen@…24…

2

Hello,

I had a question about the meaning of certain output from a LAMMPS
simulation.
After the simulation has finished running, LAMMPS outputs the number of
'procs' on which the simulation was run (for example, I have a simulation
that has output "Loop time of 52.5691 on 20 procs (20 MPI x 1 OpenMP) for
10000 steps with 19449 atoms")

What are these 'procs'? Is this simply the number of processors, or
something else?

that depends on your interpretation of "processor". with today's
hardware, this is ambiguous.
procs stands for "processor equivalents", or "tasks" or "processor
cores". so the total number of parallel tasks you told LAMMPS area
available for this instance.

axel.

3

I.e. MPI tasks specified in your mpirun command.

Steve

4

I.e. MPI tasks specified in your mpirun command.

... times the number of OpenMP threads per MPI task. :wink: