forked from lijiext/lammps
125 lines
4.8 KiB
Plaintext
125 lines
4.8 KiB
Plaintext
"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 property/atom command :h3
|
|
|
|
[Syntax:]
|
|
|
|
compute ID group-ID property/atom input1 input2 ... :pre
|
|
|
|
ID, group-ID are documented in "compute"_compute.html command :ulb,l
|
|
property/atom = style name of this compute command :l
|
|
input = one or more atom attributes :l
|
|
possible attributes = id, mol, type, mass,
|
|
x, y, z, xs, ys, zs, xu, yu, zu, ix, iy, iz,
|
|
vx, vy, vz, fx, fy, fz,
|
|
q, mux, muy, muz, mu,
|
|
radius, diameter, omegax, omegay, omegaz,
|
|
angmomx, angmomy, angmomz,
|
|
shapex,shapey, shapez,
|
|
quatw, quati, quatj, quatk, tqx, tqy, tqz,
|
|
spin, eradius, ervel, erforce
|
|
end1x, end1y, end1z, end2x, end2y, end2z,
|
|
corner1x, corner1y, corner1z,
|
|
corner2x, corner2y, corner2z,
|
|
corner3x, corner3y, corner3z :pre
|
|
id = atom ID
|
|
mol = molecule ID
|
|
type = atom type
|
|
mass = atom mass
|
|
x,y,z = unscaled atom coordinates
|
|
xs,ys,zs = scaled atom coordinates
|
|
xu,yu,zu = unwrapped atom coordinates
|
|
ix,iy,iz = box image that the atom is in
|
|
vx,vy,vz = atom velocities
|
|
fx,fy,fz = forces on atoms
|
|
q = atom charge
|
|
mux,muy,muz = orientation of dipole moment of atom
|
|
mu = magnitude of dipole moment of atom
|
|
radius,diameter = radius,diameter of spherical particle
|
|
omegax,omegay,omegaz = angular velocity of extended particle
|
|
angmomx,angmomy,angmomz = angular momentum of extended particle
|
|
shapex,shapey,shapez = 3 diameters of aspherical particle
|
|
quatw,quati,quatj,quatk = quaternion components for aspherical particles
|
|
tqx,tqy,tqz = torque on extended particles
|
|
spin = electron spin
|
|
eradius = electron radius
|
|
ervel = electron radial velocity
|
|
erforce = electron radial force
|
|
end12x, end12y, end12z = end points of line segment
|
|
coner123x, corner123y, corner123z = corner points of triangle :pre
|
|
:ule
|
|
|
|
[Examples:]
|
|
|
|
compute 1 all property/atom xs vx fx mux
|
|
compute 2 all property/atom type
|
|
compute 1 all property/atom ix iy iz :pre
|
|
|
|
[Description:]
|
|
|
|
Define a computation that simply stores atom attributes for each atom
|
|
in the group. This is useful so that the values can be used by other
|
|
"output commands"_Section_howto.html#howto_15 that take computes as
|
|
inputs. See for example, the "compute reduce"_compute_reduce.html,
|
|
"fix ave/atom"_fix_ave_atom.html, "fix ave/histo"_fix_ave_histo.html,
|
|
"fix ave/spatial"_fix_ave_spatial.html, and "atom-style
|
|
variable"_variable.html commands.
|
|
|
|
The list of possible attributes is the same as that used by the "dump
|
|
custom"_dump.html command, which describes their meaning, with some
|
|
additional quantities that are only defined for certain "atom
|
|
styles"_atom_style.html. Basically, this list gives your input script
|
|
access to any per-atom quantity stored by LAMMPS.
|
|
|
|
The values are stored in a per-atom vector or array as discussed
|
|
below. Zeroes are stored for atoms not in the specified group or for
|
|
quantities that are not defined for a particular particle in the group
|
|
(e.g. {shapex} if the particle is not an ellipsoid).
|
|
|
|
The additional quantities only accessible via this command, and not
|
|
directly via the "dump custom"_dump.html command, are as follows.
|
|
|
|
{Shapex}, {shapey}, and {shapez} are defined for ellipsoidal particles
|
|
and define the 3d shape of each particle. {Quatw}, {quati}, {quatj},
|
|
and {quatk} are also defined for ellipsoidal particles and store the
|
|
4-vector quaternion representing the orientation of each particle.
|
|
See the "set"_set.html command for an explanation of the quaternion
|
|
vector.
|
|
|
|
{End1x}, {end1y}, {end1z}, {end2x}, {end2y}, {end2z}, are defined for
|
|
line segment particles and define the end points of each line segment.
|
|
|
|
{Corner1x}, {corner1y}, {corner1z}, {corner2x}, {corner2y},
|
|
{corner2z}, {corner3x}, {corner3y}, {corner3z}, are defined for
|
|
triangular particles and define the corner points of each triangle.
|
|
|
|
[Output info:]
|
|
|
|
This compute calculates a per-atom vector or per-atom array depending
|
|
on the number of input values. If a single input is specified, a
|
|
per-atom vector is produced. If two or more inputs are specified, a
|
|
per-atom array is produced where the number of columns = the number of
|
|
inputs. The vector or array can be accessed by any command that uses
|
|
per-atom values from a compute as input. See "this
|
|
section"_Section_howto.html#howto_15 for an overview of LAMMPS output
|
|
options.
|
|
|
|
The vector or array values will be in whatever "units"_units.html the
|
|
corresponding attribute is in, e.g. velocity units for vx, charge
|
|
units for q, etc.
|
|
|
|
[Restrictions:] none
|
|
|
|
[Related commands:]
|
|
|
|
"dump custom"_dump.html, "compute reduce"_compute_reduce.html, "fix
|
|
ave/atom"_fix_ave_atom.html, "fix ave/spatial"_fix_ave_spatial.html
|
|
|
|
[Default:] none
|