"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)

:line

compute temp/partial command :h3

[Syntax:]

compute ID group-ID temp/partial xflag yflag zflag :pre

ID, group-ID are documented in "compute"_compute.html command
temp/partial = style name of this compute command
xflag,yflag,zflag = 0/1 for whether to exclude/include this dimension :ul

[Examples:]

compute newT flow temp/partial 1 1 0 :pre

[Description:]

Define a compute to calculate the temperature of a group of atoms,
after excluding one or more velocity components.  A compute of this
style can be used by any command that computes a temperature,
e.g. "thermo_modify"_thermo_modify.html, "fix
temp/rescale"_fix_temp_rescale.html, "fix npt"_fix_npt.html, etc.

The temperature is calculated by the formula KE = dim/2 N k T, where
KE = total kinetic energy of the group of atoms (sum of 1/2 m v^2),
dim = dimensionality of the simulation, N = number of atoms in the
group, k = Boltzmann constant, and T = temperature.  The calculation
of KE excludes the x, y, or z dimensions if xflag, yflag, or zflag =
0.  The dim parameter is adjusted to give the correct number of
degrees of freedom.

A 6-component kinetic energy tensor is also calculated by this compute
for use in the calculation of a pressure tensor.  The formula for the
components of the tensor is the same as the above formula, except that
v^2 is replaced by vx * vy for the xy component, etc.

The number of atoms contributing to the temperature is assumed to be
constant for the duration of the run; use the {dynamic} option of the
"compute_modify"_compute_modify.html command if this is not the case.

This compute subtracts out degrees-of-freedom due to fixes that
constrain molecular motion, such as "fix shake"_fix_shake.html and
"fix rigid"_fix_rigid.html.  This means the temperature of groups of
atoms that include these constraints will be computed correctly.  If
needed, the subtracted degrees-of-freedom can be altered using the
{extra} option of the "compute_modify"_compute_modify.html command.

[Restrictions:] none

[Related commands:]

"compute temp"_compute_temp.html, "compute
temp/region"_compute_temp_region.html, "compute
pressure"_compute_pressure.html

[Default:] none
