[lammps-users] Doubt on restart command

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1

Hi lammps users
I am running a series of fixes (nvt followed by few npt’s) for large timesteps. I need to break my simulation. When I wrote a restart file after nvt run and read the restart file for npt run, I could observe that the temperature started from zero again. The final temperature from nvt run was 300 K. Is it possible to restart the simulation from the same temperature?
Regards
Abhiram

2

there is not enough information here to make a meaningful assessment of what is going on, so I have to resolve to blind guessing.
if you are talking about ramping the temperature then you should look at the “start” and “stop” keywords of the run command.
if this guess is not correct, you need to provide more details and explanations of what you are doing and what is going wrong.

best if you could provide a “minimal” example by modifying one of the example input files.

axel.

3

Thanks for your reply. Sorry that my question was not clear. I did not mean ramping temperature. I have attached a baby code here. In the log file, after nvt simulation, the temperature is 97 K, and npt starts at the same 97 K. But if you split this code into two, read a restart file after nvt simulation and start npt, the temperature begins from 0 K. Is it possible to start from the same temperature where nvt simulation ended? I hope my question is clear.

Regards
Abhiram

log.lammps (18.9 KB)

in.polyethylene (1.25 KB)

few_atoms.data (186 KB)

4

you are issuing the “write_restart” commands before the run and not after.
that means your restart will write down the current state before a run, i.e. at T = 0K for the nvt file.

axel.