Temperature of the system varying too rapidly

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1

I’m currently trying to simulate a group of particles called active particles. This system is basically a bunch of particles with each having their own propulsion( the direction, propulsion are determined by certain simple rules). Hence, the energy of the system is not conserved (in the conventional sense ke+pe). But I would expect a uniform variation in temp, ke, pe and etotal. I have made the following changes in the code and the temp&ke seem to be fluctuating too rapidly. I have realized that this could be a problem as the system im trying to simulate doesn’t seem to evolve very appreciably over large time scales as the systems (well documented, see below.) have done. And these changes run perfectly for the documented systems as below.
I have attached below the changes made in the file of changes being made and log.lammps.

What might cause this?

For more info please consult these two papers:

  1. [http://dx.doi.org/10.1119/1.4870398] Simulation of the active Brownian motion of a microswimmer.
  2. [DOI: 10.1039/c3sm52813h] Phase behavior of active Brownian particles: the
    role of dimensionality. (In my system I’m trying to put the particles which follow equations 6 & 7)

changes.txt (4.64 KB)

log.lammps (44 KB)

2

Why do you need to make any changes to existing LAMMPS code?

Maybe you need to add new fixes, computes, etc to LAMMPS,

but that is different. If you have made changes to existing code,

I doubt you will find folks here that want to debug your code.

That would really be your job. Likewise, no one is likely to go

read papers that you cite.

What you could ask is explain what the model is you are trying to

adapt LAMMPS to, and ask what the best way to do that in LAMMPS is.

Steve