<p>Dump a snapshot of atom quantities to one or more files every N
timesteps in a format readable by the <aclass="reference external"href="http://www.vtk.org">VTK visualization toolkit</a> or other visualization tools that use it,
e.g. <aclass="reference external"href="http://www.paraview.org">ParaView</a>. The timesteps on which dump
output is written can also be controlled by a variable; see the
option is invoked, the lines of atom information written to dump files
will be in an indeterminate order for each snapshot. This is even
true when running on a single processor, if the <aclass="reference internal"href="atom_modify.html"><spanclass="doc">atom_modify sort</span></a> option is on, which it is by default. In this
case atoms are re-ordered periodically during a simulation, due to
spatial sorting. It is also true when running in parallel, because
data for a single snapshot is collected from multiple processors, each
of which owns a subset of the atoms.</p>
</div>
<p>For the <em>custom/vtk</em> style, sorting is off by default. See the
Additionaly, you can use <em>xs</em>, <em>ys</em>, <em>zs</em> if you want to also save the
coordinates “scaled” to the box size, so that each value is 0.0 to
1.0. If the simulation box is triclinic (tilted), then all atom
coords will still be between 0.0 and 1.0. Use <em>xu</em>, <em>yu</em>, <em>zu</em> if you
want the coordinates “unwrapped” by the image flags for each atom.
Unwrapped means that if the atom has passed through a periodic
boundary one or more times, the value is printed for what the
coordinate would be if it had not been wrapped back into the periodic
box. Note that using <em>xu</em>, <em>yu</em>, <em>zu</em> means that the coordinate
values may be far outside the box bounds printed with the snapshot.
Using <em>xsu</em>, <em>ysu</em>, <em>zsu</em> is similar to using <em>xu</em>, <em>yu</em>, <em>zu</em>, except
that the unwrapped coordinates are scaled by the box size. Atoms that
have passed through a periodic boundary will have the corresponding
cooordinate increased or decreased by 1.0.</p>
<p>The image flags can be printed directly using the <em>ix</em>, <em>iy</em>, <em>iz</em>
attributes. For periodic dimensions, they specify which image of the
simulation box the atom is considered to be in. An image of 0 means
it is inside the box as defined. A value of 2 means add 2 box lengths
to get the true value. A value of -1 means subtract 1 box length to
get the true value. LAMMPS updates these flags as atoms cross
periodic boundaries during the simulation.</p>
<p>The <em>mux</em>, <em>muy</em>, <em>muz</em> attributes are specific to dipolar systems
defined with an atom style of <em>dipole</em>. They give the orientation of
the atom’s point dipole moment. The <em>mu</em> attribute gives the
magnitude of the atom’s dipole moment.</p>
<p>The <em>radius</em> and <em>diameter</em> attributes are specific to spherical
particles that have a finite size, such as those defined with an atom
style of <em>sphere</em>.</p>
<p>The <em>omegax</em>, <em>omegay</em>, and <em>omegaz</em> attributes are specific to
finite-size spherical particles that have an angular velocity. Only
certain atom styles, such as <em>sphere</em> define this quantity.</p>
<p>The <em>angmomx</em>, <em>angmomy</em>, and <em>angmomz</em> attributes are specific to
finite-size aspherical particles that have an angular momentum. Only
the <em>ellipsoid</em> atom style defines this quantity.</p>
<p>The <em>tqx</em>, <em>tqy</em>, <em>tqz</em> attributes are for finite-size particles that
can sustain a rotational torque due to interactions with other
particles.</p>
<p>The <em>spin</em>, <em>eradius</em>, <em>ervel</em>, and <em>erforce</em> attributes are for
particles that represent nuclei and electrons modeled with the
electronic force field (EFF). See <aclass="reference internal"href="atom_style.html"><spanclass="doc">atom_style electron</span></a> and <aclass="reference internal"href="pair_eff.html"><spanclass="doc">pair_style eff</span></a> for more
details.</p>
<p>The <em>c_ID</em> and <em>c_ID[N]</em> attributes allow per-atom vectors or arrays
calculated by a <aclass="reference internal"href="compute.html"><spanclass="doc">compute</span></a> to be output. The ID in the
attribute should be replaced by the actual ID of the compute that has
been defined previously in the input script. See the
<aclass="reference internal"href="compute.html"><spanclass="doc">compute</span></a> command for details. There are computes for
calculating the per-atom energy, stress, centro-symmetry parameter,
and coordination number of individual atoms.</p>
<p>Note that computes which calculate global or local quantities, as
opposed to per-atom quantities, cannot be output in a dump custom/vtk
command. Instead, global quantities can be output by the
<aclass="reference internal"href="thermo_style.html"><spanclass="doc">thermo_style custom</span></a> command, and local quantities
can be output by the dump local command.</p>
<p>If <em>c_ID</em> is used as an attribute, then the per-atom vector calculated
by the compute is printed. If <em>c_ID[N]</em> is used, then N must be in
the range from 1-M, which will print the Nth column of the M-length
per-atom array calculated by the compute.</p>
<p>The <em>f_ID</em> and <em>f_ID[N]</em> attributes allow vector or array per-atom
quantities calculated by a <aclass="reference internal"href="fix.html"><spanclass="doc">fix</span></a> to be output. The ID in the
attribute should be replaced by the actual ID of the fix that has been
defined previously in the input script. The <aclass="reference internal"href="fix_ave_atom.html"><spanclass="doc">fix ave/atom</span></a> command is one that calculates per-atom
quantities. Since it can time-average per-atom quantities produced by
any <aclass="reference internal"href="compute.html"><spanclass="doc">compute</span></a>, <aclass="reference internal"href="fix.html"><spanclass="doc">fix</span></a>, or atom-style
<aclass="reference internal"href="variable.html"><spanclass="doc">variable</span></a>, this allows those time-averaged results to
be written to a dump file.</p>
<p>If <em>f_ID</em> is used as a attribute, then the per-atom vector calculated
by the fix is printed. If <em>f_ID[N]</em> is used, then N must be in the
range from 1-M, which will print the Nth column of the M-length
per-atom array calculated by the fix.</p>
<p>The <em>v_name</em> attribute allows per-atom vectors calculated by a
<aclass="reference internal"href="variable.html"><spanclass="doc">variable</span></a> to be output. The name in the attribute
should be replaced by the actual name of the variable that has been
defined previously in the input script. Only an atom-style variable
can be referenced, since it is the only style that generates per-atom
values. Variables of style <em>atom</em> can reference individual atom
attributes, per-atom atom attributes, thermodynamic keywords, or
invoke other computes, fixes, or variables when they are evaluated, so
this is a very general means of creating quantities to output to a
dump file.</p>
<p>See <aclass="reference internal"href="Section_modify.html"><spanclass="doc">Section_modify</span></a> of the manual for information
on how to add new compute and fix styles to LAMMPS to calculate
per-atom quantities which could then be output into dump files.</p>
</div>
<hrclass="docutils"/>
<divclass="section"id="restrictions">
<h2>Restrictions</h2>
<p>The <em>custom/vtk</em> style does not support writing of gzipped dump files.</p>
<p>The <em>custom/vtk</em> dump style is part of the USER-VTK package. It is
only enabled if LAMMPS was built with that package. See the <aclass="reference internal"href="Section_start.html#start-3"><spanclass="std std-ref">Making LAMMPS</span></a> section for more info.</p>
<p>To use this dump style, you also must link to the VTK library. See
the info in lib/vtk/README and insure the Makefile.lammps file in that
directory is appropriate for your machine.</p>
<p>The <em>custom/vtk</em> dump style neither supports buffering nor custom
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