Create_atoms 0 output

LAMMPS LAMMPS General Discussion
1

Dear all
I submit a job on 2 differents systems Windows 10 18 cores Intel I9 PC and a GENOA AMD 192 core
On GENOA AMD: lammps version is 2Aug2023 update 3
On Windows 10 : 29 August 2024

I use the same run command for both computer.
mpirun (or mpiexec for Windows) -np 8 lmp -in test.lammps

On GENOA AMD only 7 molecules on 80 requested are created

...
# Simulation box
create_atoms    0 random     80 200001 mybox  mol plastics  400001 overlap 2.0 maxtry 200 units box
WARNING: Only inserted 7 particles out of 80 (src/create_atoms.cpp:855)
Created 462 atoms
  using box units in orthogonal box = (0 0 0) to (75 75 75)
  create_atoms CPU = 0.159 seconds
...

While on widows machine 80 on 80 requested are created

...
# Simulation box
create_atoms    0 random     80 200001 mybox  mol plastics  400001 overlap 2.0 maxtry 200 units box
Created 5280 atoms
  using box units in orthogonal box = (0 0 0) to (75 75 75)
  create_atoms CPU = 1.047 seconds
...

Is it a MPI problem or ?
Thanks a lot in advance
Best
Pascal

2

It is due to the different versions. There have been updates and corrections to create_atoms between the two versions, and in particular how “overlap” is applied.

3

thanks a lot Axel.
I will ask for updating the version on GENOA machine.
Best
Pascal

4

Dear Axel
Updating the lammps version to 2024 solved the issue.
Thanks a lot
Pascal

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