2006-09-22 00:22:34 +08:00
2015-07-30 22:53:28 +08:00
<!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" >
2015-12-21 23:20:41 +08:00
< title > improper_style class2 command — LAMMPS documentation< / title >
2015-07-30 22:53:28 +08:00
2006-09-22 00:22:34 +08:00
2015-07-30 22:53:28 +08:00
2006-09-22 00:22:34 +08:00
2015-07-30 22:53:28 +08:00
2006-09-22 00:22:34 +08:00
2015-07-30 22:53:28 +08:00
2006-09-22 00:22:34 +08:00
2015-07-30 22:53:28 +08:00
2006-09-22 00:22:34 +08:00
2015-07-30 22:53:28 +08:00
< 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" / >
2015-12-21 23:20:41 +08:00
< link rel = "top" title = "LAMMPS documentation" href = "index.html" / >
2015-07-30 22:53:28 +08:00
< 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 > improper_style class2 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 = "improper-style-class2-command" >
< span id = "index-0" > < / span > < h1 > improper_style class2 command< a class = "headerlink" href = "#improper-style-class2-command" title = "Permalink to this headline" > ¶< / a > < / h1 >
< / div >
< div class = "section" id = "improper-style-class2-omp-command" >
< h1 > improper_style class2/omp command< a class = "headerlink" href = "#improper-style-class2-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 > improper_style class2
< / pre > < / div >
< / div >
< / 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 > improper_style class2
2010-11-19 01:28:36 +08:00
improper_coeff 1 100.0 0
2015-07-30 22:53:28 +08:00
improper_coeff * aa 0.0 0.0 0.0 115.06 130.01 115.06
< / 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 > class2< / em > improper style uses the potential< / p >
< img alt = "_images/improper_class2.jpg" class = "align-center" src = "_images/improper_class2.jpg" / >
< p > where Ei is the improper term and Eaa is an angle-angle term. The 3 X
terms in Ei are an average over 3 out-of-plane angles.< / p >
< p > The 4 atoms in an improper quadruplet (listed in the data file read by
the < a class = "reference internal" href = "read_data.html" > < em > read_data< / em > < / a > command) are ordered I,J,K,L. X_IJKL
2007-06-28 23:07:55 +08:00
refers to the angle between the plane of I,J,K and the plane of J,K,L,
and the bond JK lies in both planes. Similarly for X_KJLI and X_LJIK.
Note that atom J appears in the common bonds (JI, JK, JL) of all 3 X
terms. Thus J (the 2nd atom in the quadruplet) is the atom of
2015-07-30 22:53:28 +08:00
symmetry in the 3 X angles.< / p >
< p > The subscripts on the various theta’ s refer to different combinations
2007-06-28 23:07:55 +08:00
of 3 atoms (I,J,K,L) used to form a particular angle. E.g. Theta_IJL
is the angle formed by atoms I,J,L with J in the middle. Theta1,
2007-06-28 23:25:31 +08:00
theta2, theta3 are the equilibrium positions of those angles. Again,
atom J (the 2nd atom in the quadruplet) is the atom of symmetry in the
2015-07-30 22:53:28 +08:00
theta angles, since it is always the center atom.< / p >
< p > Since atom J is the atom of symmetry, normally the bonds J-I, J-K, J-L
2007-06-29 05:59:10 +08:00
would exist for an improper to be defined between the 4 atoms, but
2015-07-30 22:53:28 +08:00
this is not required.< / p >
2015-12-20 02:42:24 +08:00
< p > See < a class = "reference internal" href = "pair_modify.html#sun" > < span > (Sun)< / span > < / a > for a description of the COMPASS class2 force field.< / p >
2015-07-30 22:53:28 +08:00
< p > Coefficients for the Ei and Eaa formulas must be defined for each
improper type via the < a class = "reference internal" href = "improper_coeff.html" > < em > improper_coeff< / em > < / a > command as
2010-11-18 02:20:48 +08:00
in the example above, or in the data file or restart files read by the
2015-07-30 22:53:28 +08:00
< 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.< / p >
< p > These are the 2 coefficients for the Ei formula:< / p >
< ul class = "simple" >
< li > K (energy/radian^2)< / li >
< li > X0 (degrees)< / li >
< / ul >
< p > X0 is specified in degrees, but LAMMPS converts it to radians
internally; hence the units of K are in energy/radian^2.< / p >
< p > For the Eaa formula, each line in a
< a class = "reference internal" href = "improper_coeff.html" > < em > improper_coeff< / em > < / a > command in the input script lists
7 coefficients, the first of which is “ aa” to indicate they are
2010-11-18 02:20:48 +08:00
AngleAngle coefficients. In a data file, these coefficients should be
2015-07-30 22:53:28 +08:00
listed under a “ AngleAngle Coeffs” heading and you must leave out the
“ aa” , i.e. only list 6 coefficients after the improper type.< / p >
< ul class = "simple" >
< li > aa< / li >
< li > M1 (energy/distance)< / li >
< li > M2 (energy/distance)< / li >
< li > M3 (energy/distance)< / li >
< li > theta1 (degrees)< / li >
< li > theta2 (degrees)< / li >
< li > theta3 (degrees)< / li >
< / ul >
< p > The theta values are specified in degrees, but LAMMPS converts them to
radians internally; hence the units of M are in energy/radian^2.< / 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
2014-08-15 00:30:25 +08:00
functionally the same as the corresponding style without the suffix.
They have been optimized to run faster, depending on your available
2015-07-30 22:53:28 +08:00
hardware, as discussed in < a class = "reference internal" href = "Section_accelerate.html" > < em > Section_accelerate< / em > < / a >
2014-08-15 00:30:25 +08:00
of the manual. The accelerated styles take the same arguments and
should produce the same results, except for round-off and precision
2015-07-30 22:53:28 +08:00
issues.< / p >
< p > These accelerated styles are part of the USER-CUDA, GPU, USER-INTEL,
2014-08-15 00:30:25 +08:00
KOKKOS, USER-OMP and OPT packages, respectively. They are only
2015-07-30 22:53:28 +08:00
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 > Section_accelerate< / em > < / a > of the manual for
more instructions on how to use the accelerated styles effectively.< / 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 improper style can only be used if LAMMPS was built with the
CLASS2 package. See the < a class = "reference internal" href = "Section_start.html#start-3" > < span > Making LAMMPS< / span > < / a >
section for more info on packages.< / 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 = "improper_coeff.html" > < em > improper_coeff< / em > < / a > < / p >
< p > < strong > Default:< / strong > none< / p >
< hr class = "docutils" / >
< p id = "sun" > < strong > (Sun)< / strong > Sun, J Phys Chem B 102, 7338-7364 (1998).< / p >
< / div >
< / div >
< / div >
< / div >
< footer >
< hr / >
< div role = "contentinfo" >
< p >
2015-12-11 01:23:56 +08:00
© Copyright 2013 Sandia Corporation.
2015-07-30 22:53:28 +08:00
< / 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:'./',
2015-12-21 23:20:41 +08:00
VERSION:'',
2015-07-30 22:53:28 +08:00
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 >
