Page MenuHomec4science
Files F82993769

compute_tally.html
No OneTemporary
Actions

File Metadata

Created
Sat, Sep 14, 15:22

compute_tally.html
View Options

<!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>compute force/tally command &mdash; LAMMPS 15 Dec 2015 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 15 Dec 2015 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 &amp; 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 &amp; 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>
&nbsp;
</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> &raquo;</li>
<li>compute force/tally 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="compute-force-tally-command">
<span id="index-0"></span><h1>compute force/tally command<a class="headerlink" href="#compute-force-tally-command" title="Permalink to this headline">¶</a></h1>
</div>
<div class="section" id="compute-heat-flux-tally-command">
<h1>compute heat/flux/tally command<a class="headerlink" href="#compute-heat-flux-tally-command" title="Permalink to this headline">¶</a></h1>
</div>
<div class="section" id="compute-pe-tally-command">
<h1>compute pe/tally command<a class="headerlink" href="#compute-pe-tally-command" title="Permalink to this headline">¶</a></h1>
</div>
<div class="section" id="compute-stress-tally-command">
<h1>compute stress/tally command<a class="headerlink" href="#compute-stress-tally-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>compute ID group-ID style group2-ID
</pre></div>
</div>
<ul class="simple">
<li>ID, group-ID are documented in <a class="reference internal" href="compute.html"><em>compute</em></a> command</li>
<li>style = <em>force/tally</em> or <em>pe/tally</em> or <em>stress/tally</em></li>
<li>group2-ID = group ID of second (or same) group</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>compute 1 lower force/tally upper
compute 1 left pe/tally right
compute 1 lower stress/tally lower
</pre></div>
</div>
</div>
<div class="section" id="description">
<h2>Description<a class="headerlink" href="#description" title="Permalink to this headline">¶</a></h2>
<p>Define a computation that calculates properties between two groups of
atoms by accumulating them from pairwise non-bonded computations. The
two groups can be the same. This is similar to <a class="reference internal" href="compute_group_group.html"><em>compute group/group</em></a> only that the data is
accumulated directly during the non-bonded force computation. The
computes <em>force/tally</em>, <em>pe/tally</em>, <em>stress/tally</em>, and
<em>heat/flux/tally</em> are primarily provided as example how to program
additional, more sophisticated computes using the tally mechanism.</p>
<hr class="docutils" />
<p>The pairwise contributions are computing via a callback that the
compute registers with the non-bonded pairwise force computation.
This limits the use to systems that have no bonds, no Kspace, and no
manybody interactions. On the other hand, the computation does not
have to compute forces or energies a second time and thus can be much
more efficient. The callback mechanism allows to write more complex
pairwise property computations.</p>
<hr class="docutils" />
<p><strong>Output info:</strong></p>
<p>Compute <em>pe/tally</em> calculates a global scalar (the energy) and a per
atom scalar (the contributions of the single atom to the global
scalar). Compute <em>force/tally</em> calculates a global scalar (the force
magnitude) and a per atom 3-element vector (force contribution from
each atom). Compute <em>stress/tally</em> calculates a global scalar
(average of the diagonal elements of the stress tensor) and a per atom
vector (the 6 elements of stress tensor contributions from the
individual atom).</p>
<p>Both the scalar and vector values calculated by this compute are
&#8220;extensive&#8221;.</p>
</div>
<div class="section" id="restrictions">
<h2>Restrictions<a class="headerlink" href="#restrictions" title="Permalink to this headline">¶</a></h2>
<p>This compute is part of the USER-TALLY package. It is only enabled
if LAMMPS was built with that package. See the <a class="reference internal" href="Section_start.html#start-3"><span>Making LAMMPS</span></a> section for more info.</p>
<p>Not all pair styles can be evaluated in a pairwise mode as required by
this compute. For example, 3-body and other many-body potentials,
such as <a class="reference internal" href="pair_tersoff.html"><em>Tersoff</em></a> and
<a class="reference internal" href="pair_sw.html"><em>Stillinger-Weber</em></a> cannot be used. <a class="reference internal" href="pair_eam.html"><em>EAM</em></a>
potentials only include the pair potential portion of the EAM
interaction when used by this compute, not the embedding term. Also
bonded or Kspace interactions do not contribute to this compute.</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 href="#id1"><span class="problematic" id="id2">*</span></a>compute group/group*_compute_group_group.html, <a href="#id3"><span class="problematic" id="id4">*</span></a>compute
heat/flux*_compute_heat_flux.html</p>
<p><strong>Default:</strong> none</p>
</div>
</div>
</div>
</div>
<footer>
<hr/>
<div role="contentinfo">
<p>
&copy; 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:'15 Dec 2015',
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>

Event Timeline

c4science · Help