[lammps-users] Dumping temperature of a subset of atoms?

I am new to LAMMPS and was trying to find out if there is some way to
dump the temperature of a subset of atoms to a file on a regular basis
without modifying the code. I have done my own coding for small systems
in FORTRAN but wanted to try LAMMPS out to take advantage of the
parallel code to model larger structures, but I need to track the
temperatures subsets of atoms throughout my simulation. I see I can
group the specific atoms of interest and use the temperature command to
define how temperatures are computed, but is there a way to dump the
temperature(s) of the specific atom set to a file at desired N
timesteps? Ultimately, I would like to be able to do a running average
of temperature over N timesteps.

Another minor question: When defining a region, the xlo, xhi, ylo,...
values appear to require lattice cell units as defined by the lattice
command rather than the distance units as indicated in the manual. Is
this true or am I missing something. For example:

units metal

lattice fcc 5.71902

region worldbox block 0 5 0 5 -20 20 #These appear to require lattice
cell units opposed to distance units.

create_box 1 worldbox

create_atoms 1 worldbox

Will create box bounds of:

0 28.5951

0 28.5951

-114.381 114.381

And will create a lattice filling this entire space, opposed to a box
bound of:

0 5

0 5

-20 20



The thermo_style custom command lets you print out the
termperature(s) of various groups or regions of atoms, whenever
thermodynamics is printed.

The region command has an option "units" which can be lattice
or box to specify either of the options you describe below.
Note that if you fill a periodic box with atoms (using create_atoms)
and specify the region with box units (e.g. Angstroms), then
you need to insure you the box size is correct for periodicity. The
lattice option does that for you.

See the doc pages for these commands for more details.