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

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:link(ld,Manual.html)
:link(lc,Commands_all.html)

:line

compute_modify command :h3

[Syntax:]

compute_modify compute-ID keyword value ... :pre

compute-ID = ID of the compute to modify :ulb,l
one or more keyword/value pairs may be listed :l
keyword = {extra/dof} or {extra} or {dynamic/dof} or {dynamic} :l
  {extra/dof} value = N
    N = # of extra degrees of freedom to subtract
  {extra} syntax is identical to {extra/dof}, will be disabled at some point
  {dynamic/dof} value = {yes} or {no}
    yes/no = do or do not re-compute the number of degrees of freedom (DOF) contributing to the temperature
  {dynamic} syntax is identical to {dynamic/dof}, will be disabled at some point :pre
:ule

[Examples:]

compute_modify myTemp extra/dof 0
compute_modify newtemp dynamic/dof yes extra/dof 600 :pre

[Description:]

Modify one or more parameters of a previously defined compute.  Not
all compute styles support all parameters.

The {extra/dof} or {extra} keyword refers to how many
degrees-of-freedom are subtracted (typically from 3N) as a normalizing
factor in a temperature computation.  Only computes that compute a
temperature use this option.  The default is 2 or 3 for "2d or 3d
systems"_dimension.html which is a correction factor for an ensemble
of velocities with zero total linear momentum. For compute
temp/partial, if one or more velocity components are excluded, the
value used for {extra} is scaled accordingly. You can use a negative
number for the {extra} parameter if you need to add
degrees-of-freedom.  See the "compute
temp/asphere"_compute_temp_asphere.html command for an example.

The {dynamic/dof} or {dynamic} keyword determines whether the number
of atoms N in the compute group and their associated degrees of
freedom are re-computed each time a temperature is computed.  Only
compute styles that calculate a temperature use this option.  By
default, N and their DOF are assumed to be constant.  If you are
adding atoms or molecules to the system (see the "fix
pour"_fix_pour.html, "fix deposit"_fix_deposit.html, and "fix
gcmc"_fix_gcmc.html commands) or expect atoms or molecules to be lost
(e.g. due to exiting the simulation box or via "fix
evaporate"_fix_evaporate.html), then this option should be used to
insure the temperature is correctly normalized.

NOTE: The {extra} and {dynamic} keywords should not be used as they
are deprecated (March 2017) and will eventually be disabled.  Instead,
use the equivalent {extra/dof} and {dynamic/dof} keywords.

[Restrictions:] none

[Related commands:]

"compute"_compute.html

[Default:]

The option defaults are extra/dof = 2 or 3 for 2d or 3d systems and
dynamic/dof = no.
