<span id="index-0"></span><h1>compute orientorder/atom command<a class="headerlink" href="#compute-orientorder-atom-command" title="Permalink to this headline">¶</a></h1>
<div class="section" id="syntax">
<h2>Syntax<a class="headerlink" href="#syntax" title="Permalink to this headline">¶</a></h2>
<div class="highlight-python"><div class="highlight"><pre>compute ID group-ID orientorder/atom keyword values ...
</pre></div>
</div>
<ul class="simple">
<li>ID, group-ID are documented in <a class="reference internal" href="compute.html"><em>compute</em></a> command</li>
<li>orientorder/atom = style name of this compute command</li>
<li>one or more keyword/value pairs may be appended</li>
</ul>
<pre class="literal-block">
keyword = <em>cutoff</em> or <em>nnn</em> or <em>ql</em>
<em>cutoff</em> value = distance cutoff
<em>nnn</em> value = number of nearest neighbors
<em>degrees</em> values = nlvalues, l1, l2,...
</pre>
</div>
<div class="section" id="examples">
<h2>Examples<a class="headerlink" href="#examples" title="Permalink to this headline">¶</a></h2>
<div class="highlight-python"><div class="highlight"><pre>compute 1 all orientorder/atom
The numerical values of all order parameters up to <a href="#id17"><span class="problematic" id="id18">*</span></a>Q*12
for a range of commonly encountered high-symmetry structures are given
in Table I of <a class="reference internal" href="#mickel"><span>Mickel et al.</span></a>.</p>
<p>The value of <em>Ql</em> is set to zero for atoms not in the
specified compute group, as well as for atoms that have less than
<em>nnn</em> neighbors within the distance cutoff.</p>
<p>The neighbor list needed to compute this quantity is constructed each
time the calculation is performed (i.e. each time a snapshot of atoms
is dumped). Thus it can be inefficient to compute/dump this quantity
too frequently.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">If you have a bonded system, then the settings of
<a class="reference internal" href="special_bonds.html"><em>special_bonds</em></a> command can remove pairwise
interactions between atoms in the same bond, angle, or dihedral. This
is the default setting for the <a class="reference internal" href="special_bonds.html"><em>special_bonds</em></a>
command, and means those pairwise interactions do not appear in the
neighbor list. Because this fix uses the neighbor list, it also means
those pairs will not be included in the order parameter. This
difficulty can be circumvented by writing a dump file, and using the
<a class="reference internal" href="rerun.html"><em>rerun</em></a> command to compute the order parameter for
snapshots in the dump file. The rerun script can use a
<a class="reference internal" href="special_bonds.html"><em>special_bonds</em></a> command that includes all pairs in
the neighbor list.</p>
</div>
<p><strong>Output info:</strong></p>
<p>This compute calculates a per-atom array with <em>nlvalues</em> columns, giving the
<em>Ql</em> values for each atom, which are real numbers on the range 0 <= <em>Ql</em> <= 1.</p>
<p>These values can be accessed by any command that uses
per-atom values from a compute as input. See <a class="reference internal" href="Section_howto.html#howto-15"><span>Section_howto 15</span></a> for an overview of LAMMPS output
options.</p>
</div>
<div class="section" id="restrictions">
<h2>Restrictions<a class="headerlink" href="#restrictions" title="Permalink to this headline">¶</a></h2>
<blockquote>
<div>none</div></blockquote>
</div>
<div class="section" id="related-commands">
<h2>Related commands<a class="headerlink" href="#related-commands" title="Permalink to this headline">¶</a></h2>
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