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<title>angle_style hybrid command &mdash; LAMMPS 15 May 2015 version documentation</title>
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<div class="section" id="angle-style-hybrid-command">
<span id="index-0"></span><h1>angle_style hybrid command<a class="headerlink" href="#angle-style-hybrid-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>angle_style hybrid style1 style2 ...
</pre></div>
</div>
<ul class="simple">
<li>style1,style2 = list of one or more angle styles</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>angle_style hybrid harmonic cosine
angle_coeff 1 harmonic 80.0 30.0
angle_coeff 2* cosine 50.0
</pre></div>
</div>
</div>
<div class="section" id="description">
<h2>Description<a class="headerlink" href="#description" title="Permalink to this headline"></a></h2>
<p>The <em>hybrid</em> style enables the use of multiple angle styles in one
simulation. An angle style is assigned to each angle type. For
example, angles in a polymer flow (of angle type 1) could be computed
with a <em>harmonic</em> potential and angles in the wall boundary (of angle
type 2) could be computed with a <em>cosine</em> potential. The assignment
of angle type to style is made via the <a class="reference internal" href="angle_coeff.html"><em>angle_coeff</em></a>
command or in the data file.</p>
<p>In the angle_coeff commands, the name of an angle style must be added
after the angle type, with the remaining coefficients being those
appropriate to that style. In the example above, the 2 angle_coeff
commands set angles of angle type 1 to be computed with a <em>harmonic</em>
potential with coefficients 80.0, 30.0 for K, theta0. All other angle
types (2-N) are computed with a <em>cosine</em> potential with coefficient
50.0 for K.</p>
<p>If angle coefficients are specified in the data file read via the
<a class="reference internal" href="read_data.html"><em>read_data</em></a> command, then the same rule applies.
E.g. &#8220;harmonic&#8221; or &#8220;cosine&#8221;, must be added after the angle type, for each
line in the &#8220;Angle Coeffs&#8221; section, e.g.</p>
<div class="highlight-python"><div class="highlight"><pre>Angle Coeffs
</pre></div>
</div>
<div class="highlight-python"><div class="highlight"><pre>1 harmonic 80.0 30.0
2 cosine 50.0
...
</pre></div>
</div>
<p>If <em>class2</em> is one of the angle hybrid styles, the same rule holds for
specifying additional BondBond (and BondAngle) coefficients either via
the input script or in the data file. I.e. <em>class2</em> must be added to
each line after the angle type. For lines in the BondBond (or
BondAngle) section of the data file for angle types that are not
<em>class2</em>, you must use an angle style of <em>skip</em> as a placeholder, e.g.</p>
<div class="highlight-python"><div class="highlight"><pre>BondBond Coeffs
</pre></div>
</div>
<div class="highlight-python"><div class="highlight"><pre>1 skip
2 class2 3.6512 1.0119 1.0119
...
</pre></div>
</div>
<p>Note that it is not necessary to use the angle style <em>skip</em> in the
input script, since BondBond (or BondAngle) coefficients need not be
specified at all for angle types that are not <em>class2</em>.</p>
<p>An angle style of <em>none</em> with no additional coefficients can be used
in place of an angle style, either in a input script angle_coeff
command or in the data file, if you desire to turn off interactions
for specific angle types.</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>This angle style can only be used if LAMMPS was built with the
MOLECULE package (which it is by default). See the <a class="reference internal" href="Section_start.html#start-3"><span>Making LAMMPS</span></a> section for more info on packages.</p>
<p>Unlike other angle styles, the hybrid angle style does not store angle
coefficient info for individual sub-styles in a <a class="reference internal" href="restart.html"><em>binary restart files</em></a>. Thus when retarting a simulation from a restart
file, you need to re-specify angle_coeff commands.</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="angle_coeff.html"><em>angle_coeff</em></a></p>
<p><strong>Default:</strong> none</p>
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