Increasing tasks per node causing instability

[Madison Mirelez]

Hello, 

I am attempting to do scalability testing on a NVE simulation of 7579 water molecules using the MBX potential in LAMMPS.The system consists of a 61.5 x 61.5 x 61.5 Angstrom box generated with packmol and converted to a LAMMPS data file using a python script. I have included these files under the names generate_water.inp, convert.py, and waterbox.data. I also included my LAMMPS input file under in.water and my job submission file under sb.water

When I submit the job with 1 node and 1 task per node the simulation runs smoothly and remains stable. However, when I increase the tasks per node, such as using 2 tasks per node or higher, I begin to encounter problems. These problems being a steady rise in the total energy, pressure, and temperature which sometimes lead to a lost atoms error. I have noticed that as the tasks per node increase so does the starting total energy and the likelihood of the simulation getting a lost atoms error. I have also noticed that the length of the minimization phase decreases. 

I am new to using MBX and generating my own LAMMPS data file so Im having trouble deciphering where the issue is stemming from. I would greatly appreciate any advice or guidance regarding this issue.

Thank You,

Madison