forked from lijiext/lammps
283 lines
11 KiB
HTML
283 lines
11 KiB
HTML
|
|
||
|
|
|
||
|
|
<!DOCTYPE html>
|
||
|
|
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
|
||
|
|
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
|
||
|
|
<head>
|
||
|
|
<meta charset="utf-8">
|
||
|
|
|
||
|
|
<meta name="viewport" content="width=device-width, initial-scale=1.0">
|
||
|
|
|
||
|
|
<title>min_style command — LAMMPS documentation</title>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<link rel="stylesheet" href="_static/css/theme.css" type="text/css" />
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<link rel="stylesheet" href="_static/sphinxcontrib-images/LightBox2/lightbox2/css/lightbox.css" type="text/css" />
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<link rel="top" title="LAMMPS documentation" href="index.html"/>
|
||
|
|
|
||
|
|
|
||
|
|
<script src="_static/js/modernizr.min.js"></script>
|
||
|
|
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body class="wy-body-for-nav" role="document">
|
||
|
|
|
||
|
|
<div class="wy-grid-for-nav">
|
||
|
|
|
||
|
|
|
||
|
|
<nav data-toggle="wy-nav-shift" class="wy-nav-side">
|
||
|
|
<div class="wy-side-nav-search">
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<a href="Manual.html" class="icon icon-home"> LAMMPS
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</a>
|
||
|
|
|
||
|
|
|
||
|
|
<div role="search">
|
||
|
|
<form id="rtd-search-form" class="wy-form" action="search.html" method="get">
|
||
|
|
<input type="text" name="q" placeholder="Search docs" />
|
||
|
|
<input type="hidden" name="check_keywords" value="yes" />
|
||
|
|
<input type="hidden" name="area" value="default" />
|
||
|
|
</form>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
|
||
|
|
</div>
|
||
|
|
|
||
|
|
<div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<ul>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_intro.html">1. Introduction</a></li>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_start.html">2. Getting Started</a></li>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_commands.html">3. Commands</a></li>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_packages.html">4. Packages</a></li>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_accelerate.html">5. Accelerating LAMMPS performance</a></li>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_howto.html">6. How-to discussions</a></li>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_example.html">7. Example problems</a></li>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_perf.html">8. Performance & scalability</a></li>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_tools.html">9. Additional tools</a></li>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_modify.html">10. Modifying & extending LAMMPS</a></li>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_python.html">11. Python interface to LAMMPS</a></li>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_errors.html">12. Errors</a></li>
|
||
|
|
<li class="toctree-l1"><a class="reference internal" href="Section_history.html">13. Future and history</a></li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</div>
|
||
|
|
|
||
|
|
</nav>
|
||
|
|
|
||
|
|
<section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">
|
||
|
|
|
||
|
|
|
||
|
|
<nav class="wy-nav-top" role="navigation" aria-label="top navigation">
|
||
|
|
<i data-toggle="wy-nav-top" class="fa fa-bars"></i>
|
||
|
|
<a href="Manual.html">LAMMPS</a>
|
||
|
|
</nav>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<div class="wy-nav-content">
|
||
|
|
<div class="rst-content">
|
||
|
|
<div role="navigation" aria-label="breadcrumbs navigation">
|
||
|
|
<ul class="wy-breadcrumbs">
|
||
|
|
<li><a href="Manual.html">Docs</a> »</li>
|
||
|
|
|
||
|
|
<li>min_style command</li>
|
||
|
|
<li class="wy-breadcrumbs-aside">
|
||
|
|
|
||
|
|
|
||
|
|
<a href="http://lammps.sandia.gov">Website</a>
|
||
|
|
<a href="Section_commands.html#comm">Commands</a>
|
||
|
|
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
<hr/>
|
||
|
|
|
||
|
|
</div>
|
||
|
|
<div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
|
||
|
|
<div itemprop="articleBody">
|
||
|
|
|
||
|
|
<div class="section" id="min-style-command">
|
||
|
|
<span id="index-0"></span><h1>min_style command</h1>
|
||
|
|
<div class="section" id="syntax">
|
||
|
|
<h2>Syntax</h2>
|
||
|
|
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">min_style</span> <span class="n">style</span>
|
||
|
|
</pre></div>
|
||
|
|
</div>
|
||
|
|
<ul class="simple">
|
||
|
|
<li>style = <em>cg</em> or <em>hftn</em> or <em>sd</em> or <em>quickmin</em> or <em>fire</em></li>
|
||
|
|
</ul>
|
||
|
|
</div>
|
||
|
|
<div class="section" id="examples">
|
||
|
|
<h2>Examples</h2>
|
||
|
|
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">min_style</span> <span class="n">cg</span>
|
||
|
|
<span class="n">min_style</span> <span class="n">fire</span>
|
||
|
|
</pre></div>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
<div class="section" id="description">
|
||
|
|
<h2>Description</h2>
|
||
|
|
<p>Choose a minimization algorithm to use when a <a class="reference internal" href="minimize.html"><span class="doc">minimize</span></a>
|
||
|
|
command is performed.</p>
|
||
|
|
<p>Style <em>cg</em> is the Polak-Ribiere version of the conjugate gradient (CG)
|
||
|
|
algorithm. At each iteration the force gradient is combined with the
|
||
|
|
previous iteration information to compute a new search direction
|
||
|
|
perpendicular (conjugate) to the previous search direction. The PR
|
||
|
|
variant affects how the direction is chosen and how the CG method is
|
||
|
|
restarted when it ceases to make progress. The PR variant is thought
|
||
|
|
to be the most effective CG choice for most problems.</p>
|
||
|
|
<p>Style <em>hftn</em> is a Hessian-free truncated Newton algorithm. At each
|
||
|
|
iteration a quadratic model of the energy potential is solved by a
|
||
|
|
conjugate gradient inner iteration. The Hessian (second derivatives)
|
||
|
|
of the energy is not formed directly, but approximated in each
|
||
|
|
conjugate search direction by a finite difference directional
|
||
|
|
derivative. When close to an energy minimum, the algorithm behaves
|
||
|
|
like a Newton method and exhibits a quadratic convergence rate to high
|
||
|
|
accuracy. In most cases the behavior of <em>hftn</em> is similar to <em>cg</em>,
|
||
|
|
but it offers an alternative if <em>cg</em> seems to perform poorly. This
|
||
|
|
style is not affected by the <a class="reference internal" href="min_modify.html"><span class="doc">min_modify</span></a> command.</p>
|
||
|
|
<p>Style <em>sd</em> is a steepest descent algorithm. At each iteration, the
|
||
|
|
search direction is set to the downhill direction corresponding to the
|
||
|
|
force vector (negative gradient of energy). Typically, steepest
|
||
|
|
descent will not converge as quickly as CG, but may be more robust in
|
||
|
|
some situations.</p>
|
||
|
|
<p>Style <em>quickmin</em> is a damped dynamics method described in
|
||
|
|
<a class="reference internal" href="#sheppard"><span class="std std-ref">(Sheppard)</span></a>, where the damping parameter is related to the
|
||
|
|
projection of the velocity vector along the current force vector for
|
||
|
|
each atom. The velocity of each atom is initialized to 0.0 by this
|
||
|
|
style, at the beginning of a minimization.</p>
|
||
|
|
<p>Style <em>fire</em> is a damped dynamics method described in
|
||
|
|
<a class="reference internal" href="#bitzek"><span class="std std-ref">(Bitzek)</span></a>, which is similar to <em>quickmin</em> but adds a variable
|
||
|
|
timestep and alters the projection operation to maintain components of
|
||
|
|
the velocity non-parallel to the current force vector. The velocity
|
||
|
|
of each atom is initialized to 0.0 by this style, at the beginning of
|
||
|
|
a minimization.</p>
|
||
|
|
<p>Either the <em>quickmin</em> and <em>fire</em> styles are useful in the context of
|
||
|
|
nudged elastic band (NEB) calculations via the <a class="reference internal" href="neb.html"><span class="doc">neb</span></a> command.</p>
|
||
|
|
<div class="admonition note">
|
||
|
|
<p class="first admonition-title">Note</p>
|
||
|
|
<p class="last">The damped dynamic minimizers use whatever timestep you have
|
||
|
|
defined via the <a class="reference internal" href="timestep.html"><span class="doc">timestep</span></a> command. Often they will
|
||
|
|
converge more quickly if you use a timestep about 10x larger than you
|
||
|
|
would normally use for dynamics simulations.</p>
|
||
|
|
</div>
|
||
|
|
<div class="admonition note">
|
||
|
|
<p class="first admonition-title">Note</p>
|
||
|
|
<p class="last">The <em>quickmin</em> and <em>fire</em> styles do not yet support the use of
|
||
|
|
the <a class="reference internal" href="fix_box_relax.html"><span class="doc">fix box/relax</span></a> command or minimizations
|
||
|
|
involving the electron radius in <a class="reference internal" href="pair_eff.html"><span class="doc">eFF</span></a> models.</p>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
<div class="section" id="restrictions">
|
||
|
|
<h2>Restrictions</h2>
|
||
|
|
<blockquote>
|
||
|
|
<div>none</div></blockquote>
|
||
|
|
</div>
|
||
|
|
<div class="section" id="related-commands">
|
||
|
|
<h2>Related commands</h2>
|
||
|
|
<p><a class="reference internal" href="min_modify.html"><span class="doc">min_modify</span></a>, <a class="reference internal" href="minimize.html"><span class="doc">minimize</span></a>, <a class="reference internal" href="neb.html"><span class="doc">neb</span></a></p>
|
||
|
|
</div>
|
||
|
|
<div class="section" id="default">
|
||
|
|
<h2>Default</h2>
|
||
|
|
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">min_style</span> <span class="n">cg</span>
|
||
|
|
</pre></div>
|
||
|
|
</div>
|
||
|
|
<hr class="docutils" />
|
||
|
|
<p id="sheppard"><strong>(Sheppard)</strong> Sheppard, Terrell, Henkelman, J Chem Phys, 128, 134106
|
||
|
|
(2008). See ref 1 in this paper for original reference to Qmin in
|
||
|
|
Jonsson, Mills, Jacobsen.</p>
|
||
|
|
<p id="bitzek"><strong>(Bitzek)</strong> Bitzek, Koskinen, Gahler, Moseler, Gumbsch, Phys Rev Lett,
|
||
|
|
97, 170201 (2006).</p>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
<footer>
|
||
|
|
|
||
|
|
|
||
|
|
<hr/>
|
||
|
|
|
||
|
|
<div role="contentinfo">
|
||
|
|
<p>
|
||
|
|
© Copyright 2013 Sandia Corporation.
|
||
|
|
</p>
|
||
|
|
</div>
|
||
|
|
Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>.
|
||
|
|
|
||
|
|
</footer>
|
||
|
|
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
</section>
|
||
|
|
|
||
|
|
</div>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<script type="text/javascript">
|
||
|
|
var DOCUMENTATION_OPTIONS = {
|
||
|
|
URL_ROOT:'./',
|
||
|
|
VERSION:'',
|
||
|
|
COLLAPSE_INDEX:false,
|
||
|
|
FILE_SUFFIX:'.html',
|
||
|
|
HAS_SOURCE: true
|
||
|
|
};
|
||
|
|
</script>
|
||
|
|
<script type="text/javascript" src="_static/jquery.js"></script>
|
||
|
|
<script type="text/javascript" src="_static/underscore.js"></script>
|
||
|
|
<script type="text/javascript" src="_static/doctools.js"></script>
|
||
|
|
<script type="text/javascript" src="https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
|
||
|
|
<script type="text/javascript" src="_static/sphinxcontrib-images/LightBox2/lightbox2/js/jquery-1.11.0.min.js"></script>
|
||
|
|
<script type="text/javascript" src="_static/sphinxcontrib-images/LightBox2/lightbox2/js/lightbox.min.js"></script>
|
||
|
|
<script type="text/javascript" src="_static/sphinxcontrib-images/LightBox2/lightbox2-customize/jquery-noconflict.js"></script>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<script type="text/javascript" src="_static/js/theme.js"></script>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
<script type="text/javascript">
|
||
|
|
jQuery(function () {
|
||
|
|
SphinxRtdTheme.StickyNav.enable();
|
||
|
|
});
|
||
|
|
</script>
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|