<li>Nstep = snapshot timestep to read from file</li>
<li>one or more fields may be appended</li>
</ul>
<pre class="literal-block">
field = <em>x</em> or <em>y</em> or <em>z</em> or <em>vx</em> or <em>vy</em> or <em>vz</em> or <em>q</em> or <em>ix</em> or <em>iy</em> or <em>iz</em>
<em>x</em>,*y*,*z* = atom coordinates
<em>vx</em>,*vy*,*vz* = velocity components
<em>q</em> = charge
<em>ix</em>,*iy*,*iz* = image flags in each dimension
</pre>
<ul class="simple">
<li>zero or more keyword/value pairs may be appended</li>
<li>keyword = <em>box</em> or <em>replace</em> or <em>purge</em> or <em>trim</em> or <em>add</em> or <em>label</em> or <em>scaled</em> or <em>wrapped</em> or <em>format</em></li>
</ul>
<pre class="literal-block">
<em>box</em> value = <em>yes</em> or <em>no</em> = replace simulation box with dump box
<em>replace</em> value = <em>yes</em> or <em>no</em> = overwrite atoms with dump atoms
<em>purge</em> value = <em>yes</em> or <em>no</em> = delete all atoms before adding dump atoms
<em>trim</em> value = <em>yes</em> or <em>no</em> = trim atoms not in dump snapshot
<em>add</em> value = <em>yes</em> or <em>no</em> = add new dump atoms to system
<em>label</em> value = field column
field = one of the listed fields or <em>id</em> or <em>type</em>
column = label on corresponding column in dump file
<em>scaled</em> value = <em>yes</em> or <em>no</em> = coords in dump file are scaled/unscaled
<em>wrapped</em> value = <em>yes</em> or <em>no</em> = coords in dump file are wrapped/unwrapped
<em>format</em> values = format of dump file, must be last keyword if used
<p>Atom coordinates read from the dump file are first converted into
unscaled coordinates, relative to the box dimensions of the snapshot.
These coordinates are then be assigned to an existing or new atom in
the current simulation. The coordinates will then be remapped to the
simulation box, whether it is the original box or the dump snapshot
box. If periodic boundary conditions apply, this means the atom will
be remapped back into the simulation box if necessary. If shrink-wrap
boundary conditions apply, the new coordinates may change the
simulation box dimensions. If fixed boundary conditions apply, the
atom will be lost if it is outside the simulation box.</p>
<p>For <em>native</em> format dump files, the 3 xyz image flags for an atom in
the dump file are set to the corresponding values appearing in the
dump file if the <em>ix</em>, <em>iy</em>, <em>iz</em> fields are specified. If not
specified, the image flags for replaced atoms are not changed and
image flags for new atoms are set to default values. If coordinates
read from the dump file are in unwrapped format (e.g. <em>xu</em>) then the
image flags for read-in atoms are also set to default values. The
remapping procedure described in the previous paragraph will then
change images flags for all atoms (old and new) if periodic boundary
conditions are applied to remap an atom back into the simulation box.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">If you get a warning about inconsistent image flags after
reading in a dump snapshot, it means one or more pairs of bonded atoms
now have inconsistent image flags. As discussed in <a class="reference internal" href="Section_errors.html"><em>Section errors</em></a> this may or may not cause problems for
subsequent simulations, One way this can happen is if you read image
flag fields from the dump file but do not also use the dump file box
parameters.</p>
</div>
<p>LAMMPS knows how to compute unscaled and remapped coordinates for the
snapshot column labels discussed above, e.g. <em>x</em>, <em>xs</em>, <em>xu</em>, <em>xsu</em>.
If another column label is assigned to the <em>x</em> or <em>y</em> or <em>z</em> field via
the <em>label</em> keyword, e.g. for coordinates output by the <a class="reference internal" href="fix_ave_atom.html"><em>fix ave/atom</em></a> command, then LAMMPS needs to know whether
the coordinate information in the dump file is scaled and/or wrapped.
This can be set via the <em>scaled</em> and <em>wrapped</em> keywords. Note that
the value of the <em>scaled</em> and <em>wrapped</em> keywords is ignored for fields
<em>x</em> or <em>y</em> or <em>z</em> if the <em>label</em> keyword is not used to assign a
column label to that field.</p>
<p>The scaled/unscaled and wrapped/unwrapped setting must be identical
for any of the <em>x</em>, <em>y</em>, <em>z</em> fields that are specified. Thus you
cannot read <em>xs</em> and <em>yu</em> from the dump file. Also, if the dump file
coordinates are scaled and the simulation box is triclinic, then all 3
of the <em>x</em>, <em>y</em>, <em>z</em> fields must be specified, since they are all
needed to generate absolute, unscaled coordinates.</p>
</div>
<hr class="docutils" />
<div class="section" id="restrictions">
<h2>Restrictions<a class="headerlink" href="#restrictions" title="Permalink to this headline">¶</a></h2>
<p>To read gzipped dump files, you must compile LAMMPS with the
-DLAMMPS_GZIP option - see the <a class="reference internal" href="Section_start.html#start-2"><span>Making LAMMPS</span></a> section of the documentation.</p>
<p>The <em>molfile</em> dump file formats are part of the USER-MOLFILE package.
They are only enabled if LAMMPS was built with that packages. See the
<a class="reference internal" href="Section_start.html#start-3"><span>Making LAMMPS</span></a> section for more info.</p>
</div>
<div class="section" id="related-commands">
<h2>Related commands<a class="headerlink" href="#related-commands" title="Permalink to this headline">¶</a></h2>
Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>.