<p>Zero out the force and torque on a granular particle. This is useful
for preventing certain particles from moving in a simulation. The
<aclass="reference internal"href="pair_gran.html"><spanclass="doc">granular pair styles</span></a> also detect if this fix has been
defined and compute interactions between frozen and non-frozen
particles appropriately, as if the frozen particle has infinite mass.
A similar functionality for normal (point) particles can be obtained
using <aclass="reference internal"href="fix_setforce.html"><spanclass="doc">fix setforce</span></a>.</p>
<hrclass="docutils"/>
<p>Styles with a 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
<aclass="reference internal"href="Section_accelerate.html"><spanclass="doc">Section 5</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 <aclass="reference internal"href="Section_start.html#start-3"><spanclass="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 <aclass="reference internal"href="Section_start.html#start-7"><spanclass="std std-ref">-suffix command-line switch</span></a> when you invoke LAMMPS, or you can
use the <aclass="reference internal"href="suffix.html"><spanclass="doc">suffix</span></a> command in your input script.</p>
<p>See <aclass="reference internal"href="Section_accelerate.html"><spanclass="doc">Section 5</span></a> of the manual for
more instructions on how to use the accelerated styles effectively.</p>
<hrclass="docutils"/>
<p><strong>Restart, fix_modify, output, run start/stop, minimize info:</strong></p>
<p>No information about this fix is written to <aclass="reference internal"href="restart.html"><spanclass="doc">binary restart files</span></a>. None of the <aclass="reference internal"href="fix_modify.html"><spanclass="doc">fix_modify</span></a> options
are relevant to this fix.</p>
<p>This fix computes a global 3-vector of forces, which can be accessed
by various <aclass="reference internal"href="Section_howto.html#howto-15"><spanclass="std std-ref">output commands</span></a>. This is the
total force on the group of atoms before the forces on individual
atoms are changed by the fix. The vector values calculated by this
fix are “extensive”.</p>
<p>No parameter of this fix can be used with the <em>start/stop</em> keywords of
the <aclass="reference internal"href="run.html"><spanclass="doc">run</span></a> command. This fix is not invoked during <aclass="reference internal"href="minimize.html"><spanclass="doc">energy minimization</span></a>.</p>
</div>
<divclass="section"id="restrictions">
<h2>Restrictions</h2>
<p>This fix is part of the GRANULAR 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>There can only be a single freeze fix defined. This is because other
the <aclass="reference internal"href="pair_gran.html"><spanclass="doc">granular pair styles</span></a> treat frozen particles
differently and need to be able to reference a single group to which
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