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<div class="section" id="fix-nve-sphere-command">
<span id="index-0"></span><h1>fix nve/sphere command</h1>
</div>
<div class="section" id="fix-nve-sphere-omp-command">
<h1>fix nve/sphere/omp command</h1>
<div class="section" id="syntax">
<h2>Syntax</h2>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">fix</span> <span class="n">ID</span> <span class="n">group</span><span class="o">-</span><span class="n">ID</span> <span class="n">nve</span><span class="o">/</span><span class="n">sphere</span>
</pre></div>
</div>
<ul class="simple">
<li>ID, group-ID are documented in <a class="reference internal" href="fix.html"><span class="doc">fix</span></a> command</li>
<li>nve/sphere = style name of this fix command</li>
<li>zero or more keyword/value pairs may be appended</li>
</ul>
<pre class="literal-block">
keyword = <em>update</em>
<em>update</em> value = <em>dipole</em> or <em>dipole/dlm</em>
dipole = update orientation of dipole moment during integration
dipole/dlm = use DLM integrator to update dipole orientation
</pre>
</div>
<div class="section" id="examples">
<h2>Examples</h2>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">fix</span> <span class="mi">1</span> <span class="nb">all</span> <span class="n">nve</span><span class="o">/</span><span class="n">sphere</span>
<span class="n">fix</span> <span class="mi">1</span> <span class="nb">all</span> <span class="n">nve</span><span class="o">/</span><span class="n">sphere</span> <span class="n">update</span> <span class="n">dipole</span>
<span class="n">fix</span> <span class="mi">1</span> <span class="nb">all</span> <span class="n">nve</span><span class="o">/</span><span class="n">sphere</span> <span class="n">update</span> <span class="n">dipole</span><span class="o">/</span><span class="n">dlm</span>
</pre></div>
</div>
</div>
<div class="section" id="description">
<h2>Description</h2>
<p>Perform constant NVE integration to update position, velocity, and
angular velocity for finite-size spherical particles in the group each
timestep. V is volume; E is energy. This creates a system trajectory
consistent with the microcanonical ensemble.</p>
<p>This fix differs from the <a class="reference internal" href="fix_nve.html"><span class="doc">fix nve</span></a> command, which
assumes point particles and only updates their position and velocity.</p>
<p>If the <em>update</em> keyword is used with the <em>dipole</em> value, then the
orientation of the dipole moment of each particle is also updated
during the time integration. This option should be used for models
where a dipole moment is assigned to finite-size particles,
e.g. spheroids via use of the <a class="reference internal" href="atom_style.html"><span class="doc">atom_style hybrid sphere dipole</span></a> command.</p>
<p>The default dipole orientation integrator can be changed to the
Dullweber-Leimkuhler-McLachlan integration scheme
<a class="reference internal" href="fix_nh.html#nh-dullweber"><span class="std std-ref">(Dullweber)</span></a> when using <em>update</em> with the value
<em>dipole/dlm</em>. This integrator is symplectic and time-reversible,
giving better energy conservation and allows slightly longer timesteps
at only a small additional computational cost.</p>
<hr class="docutils" />
<p>Styles with a <em>gpu</em>, <em>intel</em>, <em>kk</em>, <em>omp</em>, or <em>opt</em> suffix are
functionally the same as the corresponding style without the suffix.
They have been optimized to run faster, depending on your available
hardware, as discussed in <a class="reference internal" href="Section_accelerate.html"><span class="doc">Section_accelerate</span></a>
of the manual. The accelerated styles take the same arguments and
should produce the same results, except for round-off and precision
issues.</p>
<p>These accelerated styles are part of the GPU, USER-INTEL, KOKKOS,
USER-OMP and OPT packages, respectively. They are only enabled if
LAMMPS was built with those packages. See the <a class="reference internal" href="Section_start.html#start-3"><span class="std std-ref">Making LAMMPS</span></a> section for more info.</p>
<p>You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the <a class="reference internal" href="Section_start.html#start-7"><span class="std std-ref">-suffix command-line switch</span></a> when you invoke LAMMPS, or you can
use the <a class="reference internal" href="suffix.html"><span class="doc">suffix</span></a> command in your input script.</p>
<p>See <a class="reference internal" href="Section_accelerate.html"><span class="doc">Section_accelerate</span></a> of the manual for
more instructions on how to use the accelerated styles effectively.</p>
<hr class="docutils" />
<p><strong>Restart, fix_modify, output, run start/stop, minimize info:</strong></p>
<p>No information about this fix is written to <a class="reference internal" href="restart.html"><span class="doc">binary restart files</span></a>. None of the <a class="reference internal" href="fix_modify.html"><span class="doc">fix_modify</span></a> options
are relevant to this fix. No global or per-atom quantities are stored
by this fix for access by various <a class="reference internal" href="Section_howto.html#howto-15"><span class="std std-ref">output commands</span></a>. No parameter of this fix can
be used with the <em>start/stop</em> keywords of the <a class="reference internal" href="run.html"><span class="doc">run</span></a> command.
This fix is not invoked during <a class="reference internal" href="minimize.html"><span class="doc">energy minimization</span></a>.</p>
</div>
<div class="section" id="restrictions">
<h2>Restrictions</h2>
<p>This fix requires that atoms store torque and angular velocity (omega)
and a radius as defined by the <a class="reference internal" href="atom_style.html"><span class="doc">atom_style sphere</span></a>
command. If the <em>dipole</em> keyword is used, then they must also store a
dipole moment as defined by the <a class="reference internal" href="atom_style.html"><span class="doc">atom_style dipole</span></a>
command.</p>
<p>All particles in the group must be finite-size spheres. They cannot
be point particles.</p>
</div>
<div class="section" id="related-commands">
<h2>Related commands</h2>
<p><a class="reference internal" href="fix_nve.html"><span class="doc">fix nve</span></a>, <a class="reference internal" href="fix_nve_asphere.html"><span class="doc">fix nve/asphere</span></a></p>
<p><strong>Default:</strong> none</p>
<hr class="docutils" />
<p id="nve-dullweber"><strong>(Dullweber)</strong> Dullweber, Leimkuhler and McLachlan, J Chem Phys, 107,
5840 (1997).</p>
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