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<div class="section" id="pair-style-brownian-command">
<span id="index-0"></span><h1>pair_style brownian command<a class="headerlink" href="#pair-style-brownian-command" title="Permalink to this headline">¶</a></h1>
</div>
<div class="section" id="pair-style-brownian-omp-command">
<h1>pair_style brownian/omp command<a class="headerlink" href="#pair-style-brownian-omp-command" title="Permalink to this headline">¶</a></h1>
</div>
<div class="section" id="pair-style-brownian-poly-command">
<h1>pair_style brownian/poly command<a class="headerlink" href="#pair-style-brownian-poly-command" title="Permalink to this headline">¶</a></h1>
</div>
<div class="section" id="pair-style-brownian-poly-omp-command">
<h1>pair_style brownian/poly/omp command<a class="headerlink" href="#pair-style-brownian-poly-omp-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>pair_style style mu flaglog flagfld cutinner cutoff t_target seed flagHI flagVF
</pre></div>
</div>
<ul class="simple">
<li>style = <em>brownian</em> or <em>brownian/poly</em></li>
<li>mu = dynamic viscosity (dynamic viscosity units)</li>
<li>flaglog = 0/1 log terms in the lubrication approximation on/off</li>
<li>flagfld = 0/1 to include/exclude Fast Lubrication Dynamics effects</li>
<li>cutinner = inner cutoff distance (distance units)</li>
<li>cutoff = outer cutoff for interactions (distance units)</li>
<li>t_target = target temp of the system (temperature units)</li>
<li>seed = seed for the random number generator (positive integer)</li>
<li>flagHI (optional) = 0/1 to include/exclude 1/r hydrodynamic interactions</li>
<li>flagVF (optional) = 0/1 to include/exclude volume fraction corrections in the long-range isotropic terms</li>
</ul>
</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>pair_style brownian 1.5 1 1 2.01 2.5 2.0 5878567 (assuming radius = 1)
pair_coeff 1 1 2.05 2.8
pair_coeff * *
</pre></div>
</div>
</div>
<div class="section" id="description">
<h2>Description<a class="headerlink" href="#description" title="Permalink to this headline">¶</a></h2>
<p>Styles <em>brownian</em> and <em>brownain/poly</em> compute Brownian forces and
torques on finite-size particles. The former requires monodisperse
spherical particles; the latter allows for polydisperse spherical
particles.</p>
<p>These pair styles are designed to be used with either the <a class="reference internal" href="pair_lubricate.html"><em>pair_style lubricate</em></a> or <a class="reference internal" href="pair_lubricateU.html"><em>pair_style lubricateU</em></a> commands to provide thermostatting
when dissipative lubrication forces are acting. Thus the parameters
<em>mu</em>, <em>flaglog</em>, <em>flagfld</em>, <em>cutinner</em>, and <em>cutoff</em> should be
specified consistent with the settings in the lubrication pair styles.
For details, refer to either of the lubrication pair styles.</p>
<p>The <em>t_target</em> setting is used to specify the target temperature of
the system. The random number <em>seed</em> is used to generate random
numbers for the thermostatting procedure.</p>
<p>The <em>flagHI</em> and <em>flagVF</em> settings are optional. Neither should be
used, or both must be defined.</p>
<hr class="docutils" />
<p>The following coefficients must be defined for each pair of atoms
types via the <a class="reference internal" href="pair_coeff.html"><em>pair_coeff</em></a> command as in the examples
above, or in the data file or restart files read by the
<a class="reference internal" href="read_data.html"><em>read_data</em></a> or <a class="reference internal" href="read_restart.html"><em>read_restart</em></a>
commands, or by mixing as described below:</p>
<ul class="simple">
<li>cutinner (distance units)</li>
<li>cutoff (distance units)</li>
</ul>
<p>The two coefficients are optional. If neither is specified, the two
cutoffs specified in the pair_style command are used. Otherwise both
must be specified.</p>
<hr class="docutils" />
<p>Styles with a <em>cuda</em>, <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"><em>this section</em></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 USER-CUDA, 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>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>-suffix command-line switch</span></a> when you invoke LAMMPS, or you can
use the <a class="reference internal" href="suffix.html"><em>suffix</em></a> command in your input script.</p>
<p>See <a class="reference internal" href="Section_accelerate.html"><em>this section</em></a> of the manual for more
instructions on how to use the accelerated styles effectively.</p>
<hr class="docutils" />
<p><strong>Mixing, shift, table, tail correction, restart, rRESPA info</strong>:</p>
<p>For atom type pairs I,J and I != J, the two cutoff distances for this
pair style can be mixed. The default mix value is <em>geometric</em>. See
the &#8220;pair_modify&#8221; command for details.</p>
<p>This pair style does not support the <a class="reference internal" href="pair_modify.html"><em>pair_modify</em></a>
shift option for the energy of the pair interaction.</p>
<p>The <a class="reference internal" href="pair_modify.html"><em>pair_modify</em></a> table option is not relevant
for this pair style.</p>
<p>This pair style does not support the <a class="reference internal" href="pair_modify.html"><em>pair_modify</em></a>
tail option for adding long-range tail corrections to energy and
pressure.</p>
<p>This pair style writes its information to <a class="reference internal" href="restart.html"><em>binary restart files</em></a>, so pair_style and pair_coeff commands do not need
to be specified in an input script that reads a restart file.</p>
<p>This pair style can only be used via the <em>pair</em> keyword of the
<a class="reference internal" href="run_style.html"><em>run_style respa</em></a> command. It does not support the
<em>inner</em>, <em>middle</em>, <em>outer</em> keywords.</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>These styles are part of the FLD package. They are only enabled if
LAMMPS was built with that package. See the <span class="xref std std-ref">Making LAMMPS</span> section for more info.</p>
<p>Only spherical monodisperse particles are allowed for pair_style
brownian.</p>
<p>Only spherical particles are allowed for pair_style brownian/poly.</p>
</div>
<div class="section" id="related-commands">
<h2>Related commands<a class="headerlink" href="#related-commands" title="Permalink to this headline">¶</a></h2>
<p><a class="reference internal" href="pair_coeff.html"><em>pair_coeff</em></a>, <a class="reference internal" href="pair_lubricate.html"><em>pair_style lubricate</em></a>, <a class="reference internal" href="pair_lubricateU.html"><em>pair_style lubricateU</em></a></p>
</div>
<div class="section" id="default">
<h2>Default<a class="headerlink" href="#default" title="Permalink to this headline">¶</a></h2>
<p>The default settings for the optional args are flagHI = 1 and flagVF =
1.</p>
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