Report bug on Thermo

Dear LAMMPS developers

I want to print all thermo data in the log.lammps as appeared in the linux terminal. But, only those associated with minimization is written. What’s the problem?

Thanks in advance

Dear LAMMPS developers

I want to print all thermo data in the log.lammps as appeared in the linux
terminal. But, only those associated with minimization is written. What's
the problem?

the problem is likely not with LAMMPS, but somewhere between your
chair and your keyboard.

however, it is impossible to say anything specific without knowing
which LAMMPS version you are using exactly and seeing your input
script.

axel

I’m using the recently released version.
I’ve set thermo to print data every 10 steps. But, nothing is appeared in the log.lammps until at least 100 steps progress in the simulation.
So, where is the issue?

I'm using the recently released version.
I've set thermo to print data every 10 steps. But, nothing is appeared in
the log.lammps until at least 100 steps progress in the simulation.
So, where is the issue?

let me repeat:

however, it is impossible to say anything specific without knowing
which LAMMPS version you are using exactly, and seeing your input script.

with that in mind:

- "recently released" doesn't specify the version. there are stable
and unstable version. the proper and unique description of the version
of LAMMPS is the date it prints out.
- when you describe your input, you tell me your interpretation what
you think you did. i want to see *exactly* what you did and
*everything*.

considering, that you are not even able to follow very simple
instructions, it is not far fetched to assume, that there is something
in your input, that conflicts with what you claim you are doing.

axel.

9/10 times this is just a preference of your system buffer; on the supercomputer I submit I explicitly have to tell it to deliver information to the standard output with “2>&1” appended to the end of the shell command. On the other hand any other file such as a fix will release information on the requisite time-steps regardless. If you’re input file is correct, which we don’t know, there are still a million reasons this could happen with your job submission.

How should I fix this issue?

Does all the output actually appear eventually? if it doesn’t appear even when the job is done then it is another matter entirely.

The data appear in the log file during simulation, but with a few delays, say, 100 timesteps.

How can I remove this issue?

I don’t think this is an issue. In fact, it’s a feature. You don’t want your simulation to have to wait for frequent writes to disk, do you?
If you want to have it print immediately, there is an option to make the thermo output flush after every write called “flush”. Check the docs here: http://lammps.sandia.gov/doc/thermo_modify.html
However, unlike with toilets, there is a good reason to not flush in general.

There is a thermo_modify flush option to force thermo output to

the file every output step, w/out system buffering.

Steve

Haha! It would, however, be nice to be able to specify that the thermo output has be written to disk at MOST every N steps. On some machines, runs will go for a very long time without writing anything to log.lammps. On several occasions when runs on our cluster have crashed or timed-out, I’ve had to restart from an earlier restart file than I otherwise would have used, simply to avoid having gaps in the log file. This could be fixed by adding an option requiring thermo to flush whenever a restart file is written (as opposed to flushing every line).

Best,
Rob

Rob,

You are reminding me of an idea to change how output is handled, that I tried to pitch a few years back. I think it is time to revisit this idea and discuss it with Steve.

Axel