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<div class="section" id="pair-style-dpd-conservative-command">
<span id="index-0"></span><h1>pair_style dpd/conservative command</h1>
<div class="section" id="syntax">
<h2>Syntax</h2>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">pair_style</span> <span class="n">dpd</span><span class="o">/</span><span class="n">conservative</span> <span class="n">cutoff</span>
</pre></div>
</div>
<ul class="simple">
<li>cutoff = global cutoff for DPD interactions (distance units)</li>
</ul>
</div>
<div class="section" id="examples">
<h2>Examples</h2>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">pair_style</span> <span class="n">dpd</span><span class="o">/</span><span class="n">conservative</span> <span class="mf">2.5</span>
<span class="n">pair_coeff</span> <span class="o">*</span> <span class="o">*</span> <span class="mf">3.0</span> <span class="mf">2.5</span>
<span class="n">pair_coeff</span> <span class="mi">1</span> <span class="mi">1</span> <span class="mf">3.0</span>
</pre></div>
</div>
</div>
<div class="section" id="description">
<h2>Description</h2>
<p>Style <em>dpd/conservative</em> computes the conservative force for
dissipative particle dynamics (DPD). The conservative force on atom I
due to atom J is given by</p>
<img alt="_images/pair_dpd_conservative.jpg" class="align-center" src="_images/pair_dpd_conservative.jpg" />
<p>where the weighting factor, omega_ij, varies between 0 and 1, and is
chosen to have the following functional form:</p>
<img alt="_images/pair_dpd_omega.jpg" class="align-center" src="_images/pair_dpd_omega.jpg" />
<p>where Rij is a unit vector in the direction Ri - Rj, and Rc is the
cutoff. Note that alternative definitions of the weighting function
exist, but would have to be implemented as a separate pair style
command.</p>
<p>Style <em>dpd/conservative</em> differs from the other dpd styles in that the
dissipative and random forces are not computed within the pair style.</p>
<p>For style <em>dpd/conservative</em>, the pairwise energy is due only to the
conservative force term Fc, and is shifted to be zero at the cutoff
distance Rc. The pairwise virial is calculated using only the
conservative term.</p>
<p>Style <em>dpd/conservative</em> requires the following coefficients to be
defined for each pair of atoms types via the
<a class="reference internal" href="pair_coeff.html"><span class="doc">pair_coeff</span></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"><span class="doc">read_data</span></a>
or <a class="reference internal" href="read_restart.html"><span class="doc">read_restart</span></a> commands:</p>
<ul class="simple">
<li>A (force units)</li>
<li>cutoff (distance units)</li>
</ul>
<p>The last coefficient is optional. If not specified, the global DPD
cutoff is used.</p>
</div>
<hr class="docutils" />
<div class="section" id="restrictions">
<h2>Restrictions</h2>
<p>The pair style <em>dpd/conservative</em> is only available if LAMMPS is built
with the USER-DPD package.</p>
</div>
<div class="section" id="related-commands">
<h2>Related commands</h2>
<p><a class="reference internal" href="pair_coeff.html"><span class="doc">pair_coeff</span></a>, <a class="reference internal" href="pair_dpd.html"><span class="doc">pair_dpd</span></a></p>
<p><strong>Default:</strong> none</p>
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