forked from lijiext/lammps
539 lines
27 KiB
HTML
539 lines
27 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>pair_style hybrid command — LAMMPS 15 May 2015 version 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 May 2015 version 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>pair_style hybrid 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="pair-style-hybrid-command">
|
|
<span id="index-0"></span><h1>pair_style hybrid command<a class="headerlink" href="#pair-style-hybrid-command" title="Permalink to this headline">¶</a></h1>
|
|
</div>
|
|
<div class="section" id="pair-style-hybrid-omp-command">
|
|
<h1>pair_style hybrid/omp command<a class="headerlink" href="#pair-style-hybrid-omp-command" title="Permalink to this headline">¶</a></h1>
|
|
</div>
|
|
<div class="section" id="pair-style-hybrid-overlay-command">
|
|
<h1>pair_style hybrid/overlay command<a class="headerlink" href="#pair-style-hybrid-overlay-command" title="Permalink to this headline">¶</a></h1>
|
|
</div>
|
|
<div class="section" id="pair-style-hybrid-overlay-omp-command">
|
|
<h1>pair_style hybrid/overlay/omp command<a class="headerlink" href="#pair-style-hybrid-overlay-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>pair_style hybrid style1 args style2 args ...
|
|
pair_style hybrid/overlay style1 args style2 args ...
|
|
</pre></div>
|
|
</div>
|
|
<ul class="simple">
|
|
<li>style1,style2 = list of one or more pair styles and their arguments</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>pair_style hybrid lj/cut/coul/cut 10.0 eam lj/cut 5.0
|
|
pair_coeff 1*2 1*2 eam niu3
|
|
pair_coeff 3 3 lj/cut/coul/cut 1.0 1.0
|
|
pair_coeff 1*2 3 lj/cut 0.5 1.2
|
|
</pre></div>
|
|
</div>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style hybrid/overlay lj/cut 2.5 coul/long 2.0
|
|
pair_coeff * * lj/cut 1.0 1.0
|
|
pair_coeff * * coul/long
|
|
</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> and <em>hybrid/overlay</em> styles enable the use of multiple
|
|
pair styles in one simulation. With the <em>hybrid</em> style, exactly one
|
|
pair style is assigned to each pair of atom types. With the
|
|
<em>hybrid/overlay</em> style, one or more pair styles can be assigned to
|
|
each pair of atom types. The assignment of pair styles to type pairs
|
|
is made via the <a class="reference internal" href="pair_coeff.html"><em>pair_coeff</em></a> command.</p>
|
|
<p>Here are two examples of hybrid simulations. The <em>hybrid</em> style could
|
|
be used for a simulation of a metal droplet on a LJ surface. The
|
|
metal atoms interact with each other via an <em>eam</em> potential, the
|
|
surface atoms interact with each other via a <em>lj/cut</em> potential, and
|
|
the metal/surface interaction is also computed via a <em>lj/cut</em>
|
|
potential. The <em>hybrid/overlay</em> style could be used as in the 2nd
|
|
example above, where multiple potentials are superposed in an additive
|
|
fashion to compute the interaction between atoms. In this example,
|
|
using <em>lj/cut</em> and <em>coul/long</em> together gives the same result as if
|
|
the <em>lj/cut/coul/long</em> potential were used by itself. In this case,
|
|
it would be more efficient to use the single combined potential, but
|
|
in general any combination of pair potentials can be used together in
|
|
to produce an interaction that is not encoded in any single pair_style
|
|
file, e.g. adding Coulombic forces between granular particles.</p>
|
|
<p>All pair styles that will be used are listed as “sub-styles” following
|
|
the <em>hybrid</em> or <em>hybrid/overlay</em> keyword, in any order. Each
|
|
sub-style’s name is followed by its usual arguments, as illustrated in
|
|
the example above. See the doc pages of individual pair styles for a
|
|
listing and explanation of the appropriate arguments.</p>
|
|
<p>Note that an individual pair style can be used multiple times as a
|
|
sub-style. For efficiency this should only be done if your model
|
|
requires it. E.g. if you have different regions of Si and C atoms and
|
|
wish to use a Tersoff potential for pure Si for one set of atoms, and
|
|
a Tersoff potetnial for pure C for the other set (presumably with some
|
|
3rd potential for Si-C interactions), then the sub-style <em>tersoff</em>
|
|
could be listed twice. But if you just want to use a Lennard-Jones or
|
|
other pairwise potential for several different atom type pairs in your
|
|
model, then you should just list the sub-style once and use the
|
|
pair_coeff command to assign parameters for the different type pairs.</p>
|
|
<div class="admonition warning">
|
|
<p class="first admonition-title">Warning</p>
|
|
<p class="last">An exception to this option to list an individual pair
|
|
style multiple times are the pair styles implemented as Fortran
|
|
libraries: <a class="reference internal" href="pair_meam.html"><em>pair_style meam</em></a> and <a class="reference internal" href="pair_reax.html"><em>pair_style reax</em></a> (<a class="reference internal" href="pair_reax_c.html"><em>pair_style reax/c</em></a> is OK).
|
|
This is because unlike a C++ class, they can not be instantiated
|
|
multiple times, due to the manner in which they were coded in Fortran.</p>
|
|
</div>
|
|
<p>In the pair_coeff commands, the name of a pair style must be added
|
|
after the I,J type specification, with the remaining coefficients
|
|
being those appropriate to that style. If the pair style is used
|
|
multiple times in the pair_style command, then an additional numeric
|
|
argument must also be specified which is a number from 1 to M where M
|
|
is the number of times the sub-style was listed in the pair style
|
|
command. The extra number indicates which instance of the sub-style
|
|
these coefficients apply to.</p>
|
|
<p>For example, consider a simulation with 3 atom types: types 1 and 2
|
|
are Ni atoms, type 3 are LJ atoms with charges. The following
|
|
commands would set up a hybrid simulation:</p>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style hybrid eam/alloy lj/cut/coul/cut 10.0 lj/cut 8.0
|
|
pair_coeff * * eam/alloy nialhjea Ni Ni NULL
|
|
pair_coeff 3 3 lj/cut/coul/cut 1.0 1.0
|
|
pair_coeff 1*2 3 lj/cut 0.8 1.3
|
|
</pre></div>
|
|
</div>
|
|
<p>As an example of using the same pair style multiple times, consider a
|
|
simulation with 2 atom types. Type 1 is Si, type 2 is C. The
|
|
following commands would model the Si atoms with Tersoff, the C atoms
|
|
with Tersoff, and the cross-interactions with Lennard-Jones:</p>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style hybrid lj/cut 2.5 tersoff tersoff
|
|
pair_coeff * * tersoff 1 Si.tersoff Si NULL
|
|
pair_coeff * * tersoff 2 C.tersoff NULL C
|
|
pair_coeff 1 2 lj/cut 1.0 1.5
|
|
</pre></div>
|
|
</div>
|
|
<p>If pair 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. “eam/alloy” or “lj/cut” must be added after the atom type, for
|
|
each line in the “Pair Coeffs” section, e.g.</p>
|
|
<div class="highlight-python"><div class="highlight"><pre>Pair Coeffs
|
|
</pre></div>
|
|
</div>
|
|
<div class="highlight-python"><div class="highlight"><pre>1 lj/cut/coul/cut 1.0 1.0
|
|
...
|
|
</pre></div>
|
|
</div>
|
|
<p>Note that the pair_coeff command for some potentials such as
|
|
<a class="reference internal" href="pair_eam.html"><em>pair_style eam/alloy</em></a> includes a mapping specification
|
|
of elements to all atom types, which in the hybrid case, can include
|
|
atom types not assigned to the <em>eam/alloy</em> potential. The NULL
|
|
keyword is used by many such potentials (eam/alloy, Tersoff, AIREBO,
|
|
etc), to denote an atom type that will be assigned to a different
|
|
sub-style.</p>
|
|
<p>For the <em>hybrid</em> style, each atom type pair I,J is assigned to exactly
|
|
one sub-style. Just as with a simulation using a single pair style,
|
|
if you specify the same atom type pair in a second pair_coeff command,
|
|
the previous assignment will be overwritten.</p>
|
|
<p>For the <em>hybrid/overlay</em> style, each atom type pair I,J can be
|
|
assigned to one or more sub-styles. If you specify the same atom type
|
|
pair in a second pair_coeff command with a new sub-style, then the
|
|
second sub-style is added to the list of potentials that will be
|
|
calculated for two interacting atoms of those types. If you specify
|
|
the same atom type pair in a second pair_coeff command with a
|
|
sub-style that has already been defined for that pair of atoms, then
|
|
the new pair coefficients simply override the previous ones, as in the
|
|
normal usage of the pair_coeff command. E.g. these two sets of
|
|
commands are the same:</p>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style lj/cut 2.5
|
|
pair_coeff * * 1.0 1.0
|
|
pair_coeff 2 2 1.5 0.8
|
|
</pre></div>
|
|
</div>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style hybrid/overlay lj/cut 2.5
|
|
pair_coeff * * lj/cut 1.0 1.0
|
|
pair_coeff 2 2 lj/cut 1.5 0.8
|
|
</pre></div>
|
|
</div>
|
|
<p>Coefficients must be defined for each pair of atoms types via the
|
|
<a class="reference internal" href="pair_coeff.html"><em>pair_coeff</em></a> command as described above, or in the
|
|
data file or restart files read by the <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, or by mixing as described
|
|
below.</p>
|
|
<p>For both the <em>hybrid</em> and <em>hybrid/overlay</em> styles, every atom type
|
|
pair I,J (where I <= J) must be assigned to at least one sub-style via
|
|
the <a class="reference internal" href="pair_coeff.html"><em>pair_coeff</em></a> command as in the examples above, or
|
|
in the data file read by the <a class="reference internal" href="read_data.html"><em>read_data</em></a>, or by mixing
|
|
as described below.</p>
|
|
<p>If you want there to be no interactions between a particular pair of
|
|
atom types, you have 3 choices. You can assign the type pair to some
|
|
sub-style and use the <a class="reference internal" href="neigh_modify.html"><em>neigh_modify exclude type</em></a>
|
|
command. You can assign it to some sub-style and set the coefficients
|
|
so that there is effectively no interaction (e.g. epsilon = 0.0 in a
|
|
LJ potential). Or, for <em>hybrid</em> and <em>hybrid/overlay</em> simulations, you
|
|
can use this form of the pair_coeff command in your input script:</p>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_coeff 2 3 none
|
|
</pre></div>
|
|
</div>
|
|
<p>or this form in the “Pair Coeffs” section of the data file:</p>
|
|
<div class="highlight-python"><div class="highlight"><pre>3 none
|
|
</pre></div>
|
|
</div>
|
|
<p>If an assignment to <em>none</em> is made in a simulation with the
|
|
<em>hybrid/overlay</em> pair style, it wipes out all previous assignments of
|
|
that atom type pair to sub-styles.</p>
|
|
<p>Note that you may need to use an <a class="reference internal" href="atom_style.html"><em>atom_style</em></a> hybrid
|
|
command in your input script, if atoms in the simulation will need
|
|
attributes from several atom styles, due to using multiple pair
|
|
potentials.</p>
|
|
<hr class="docutils" />
|
|
<p>Different force fields (e.g. CHARMM vs AMBER) may have different rules
|
|
for applying weightings that change the strength of pairwise
|
|
interactions bewteen pairs of atoms that are also 1-2, 1-3, and 1-4
|
|
neighbors in the molecular bond topology, as normally set by the
|
|
<a class="reference internal" href="special_bonds.html"><em>special_bonds</em></a> command. Different weights can be
|
|
assigned to different pair hybrid sub-styles via the <a class="reference internal" href="pair_modify.html"><em>pair_modify special</em></a> command. This allows multiple force fields
|
|
to be used in a model of a hybrid system, however, there is no consistent
|
|
approach to determine parameters automatically for the interactions
|
|
between the two force fields, this is only recommended when particles
|
|
described by the different force fields do not mix.</p>
|
|
<p>Here is an example for mixing CHARMM and AMBER: The global <em>amber</em>
|
|
setting sets the 1-4 interactions to non-zero scaling factors and
|
|
then overrides them with 0.0 only for CHARMM:</p>
|
|
<div class="highlight-python"><div class="highlight"><pre>special_bonds amber
|
|
pair_hybrid lj/charmm/coul/long 8.0 10.0 lj/cut/coul/long 10.0
|
|
pair_modify pair lj/charmm/coul/long special lj/coul 0.0 0.0 0.0
|
|
</pre></div>
|
|
</div>
|
|
<p>The this input achieves the same effect:</p>
|
|
<div class="highlight-python"><div class="highlight"><pre>special_bonds 0.0 0.0 0.1
|
|
pair_hybrid lj/charmm/coul/long 8.0 10.0 lj/cut/coul/long 10.0
|
|
pair_modify pair lj/cut/coul/long special lj 0.0 0.0 0.5
|
|
pair_modify pair lj/cut/coul/long special coul 0.0 0.0 0.83333333
|
|
pair_modify pair lj/charmm/coul/long special lj/coul 0.0 0.0 0.0
|
|
</pre></div>
|
|
</div>
|
|
<p>Here is an example for mixing Tersoff with OPLS/AA based on
|
|
a data file that defines bonds for all atoms where for the
|
|
Tersoff part of the system the force constants for the bonded
|
|
interactions have been set to 0. Note the global settings are
|
|
effectively <em>lj/coul 0.0 0.0 0.5</em> as required for OPLS/AA:</p>
|
|
<div class="highlight-python"><div class="highlight"><pre>special_bonds lj/coul 1e-20 1e-20 0.5
|
|
pair_hybrid tersoff lj/cut/coul/long 12.0
|
|
pair_modify pair tersoff special lj/coul 1.0 1.0 1.0
|
|
</pre></div>
|
|
</div>
|
|
<p>See the <a class="reference internal" href="pair_modify.html"><em>pair_modify</em></a> doc page for details on
|
|
the specific syntax, requirements and restrictions.</p>
|
|
<hr class="docutils" />
|
|
<p>The potential energy contribution to the overall system due to an
|
|
individual sub-style can be accessed and output via the <a class="reference internal" href="compute_pair.html"><em>compute pair</em></a> command.</p>
|
|
<hr class="docutils" />
|
|
<p>IMPORTANT: Several of the potentials defined via the pair_style
|
|
command in LAMMPS are really many-body potentials, such as Tersoff,
|
|
AIREBO, MEAM, ReaxFF, etc. The way to think about using these
|
|
potentials in a hybrid setting is as follows.</p>
|
|
<p>A subset of atom types is assigned to the many-body potential with a
|
|
single <a class="reference internal" href="pair_coeff.html"><em>pair_coeff</em></a> command, using “* <a href="#id1"><span class="problematic" id="id2">*</span></a>” to include
|
|
all types and the NULL keywords described above to exclude specific
|
|
types not assigned to that potential. If types 1,3,4 were assigned in
|
|
that way (but not type 2), this means that all many-body interactions
|
|
between all atoms of types 1,3,4 will be computed by that potential.
|
|
Pair_style hybrid allows interactions between type pairs 2-2, 1-2,
|
|
2-3, 2-4 to be specified for computation by other pair styles. You
|
|
could even add a second interaction for 1-1 to be computed by another
|
|
pair style, assuming pair_style hybrid/overlay is used.</p>
|
|
<p>But you should not, as a general rule, attempt to exclude the
|
|
many-body interactions for some subset of the type pairs within the
|
|
set of 1,3,4 interactions, e.g. exclude 1-1 or 1-3 interactions. That
|
|
is not conceptually well-defined for many-body interactions, since the
|
|
potential will typically calculate energies and foces for small groups
|
|
of atoms, e.g. 3 or 4 atoms, using the neighbor lists of the atoms to
|
|
find the additional atoms in the group. It is typically non-physical
|
|
to think of excluding an interaction between a particular pair of
|
|
atoms when the potential computes 3-body or 4-body interactions.</p>
|
|
<p>However, you can still use the pair_coeff none setting or the
|
|
<a class="reference internal" href="neigh_modify.html"><em>neigh_modify exclude</em></a> command to exclude certain
|
|
type pairs from the neighbor list that will be passed to a manybody
|
|
sub-style. This will alter the calculations made by a many-body
|
|
potential, since it builds its list of 3-body, 4-body, etc
|
|
interactions from the pair list. You will need to think carefully as
|
|
to whether it produces a physically meaningful result for your model.</p>
|
|
<p>For example, imagine you have two atom types in your model, type 1 for
|
|
atoms in one surface, and type 2 for atoms in the other, and you wish
|
|
to use a Tersoff potential to compute interactions within each
|
|
surface, but not between surfaces. Then either of these two command
|
|
sequences would implement that model:</p>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style hybrid tersoff
|
|
pair_coeff * * tersoff SiC.tersoff C C
|
|
pair_coeff 1 2 none
|
|
</pre></div>
|
|
</div>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style tersoff
|
|
pair_coeff * * SiC.tersoff C C
|
|
neigh_modify exclude type 1 2
|
|
</pre></div>
|
|
</div>
|
|
<p>Either way, only neighbor lists with 1-1 or 2-2 interactions would be
|
|
passed to the Tersoff potential, which means it would compute no
|
|
3-body interactions containing both type 1 and 2 atoms.</p>
|
|
<p>Here is another example, using hybrid/overlay, to use 2 many-body
|
|
potentials together, in an overlapping manner. Imagine you have CNT
|
|
(C atoms) on a Si surface. You want to use Tersoff for Si/Si and Si/C
|
|
interactions, and AIREBO for C/C interactions. Si atoms are type 1; C
|
|
atoms are type 2. Something like this will work:</p>
|
|
<div class="highlight-python"><div class="highlight"><pre>pair_style hybrid/overlay tersoff airebo 3.0
|
|
pair_coeff * * tersoff SiC.tersoff.custom Si C
|
|
pair_coeff * * airebo CH.airebo NULL C
|
|
</pre></div>
|
|
</div>
|
|
<p>Note that to prevent the Tersoff potential from computing C/C
|
|
interactions, you would need to modify the SiC.tersoff file to turn
|
|
off C/C interaction, i.e. by setting the appropriate coefficients to
|
|
0.0.</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
|
|
functionally the same as the corresponding style without the suffix.
|
|
They have been optimized to run faster, depending on your available
|
|
hardware, as discussed in <a class="reference internal" href="Section_accelerate.html"><em>Section_accelerate</em></a>
|
|
of the manual.</p>
|
|
<p>Since the <em>hybrid</em> and <em>hybrid/overlay</em> styles delegate computation
|
|
to the individual sub-styles, the suffix versions of the <em>hybrid</em>
|
|
and <em>hybrid/overlay</em> styles are used to propagate the corresponding
|
|
suffix to all sub-styles, if those versions exist. Otherwise the
|
|
non-accelerated version will be used.</p>
|
|
<p>The individual accelerated sub-styles are part of the USER-CUDA, GPU,
|
|
USER-OMP and OPT packages, respectively. They are only 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>
|
|
<hr class="docutils" />
|
|
<p><strong>Mixing, shift, table, tail correction, restart, rRESPA info</strong>:</p>
|
|
<p>Any pair potential settings made via the
|
|
<a class="reference internal" href="pair_modify.html"><em>pair_modify</em></a> command are passed along to all
|
|
sub-styles of the hybrid potential.</p>
|
|
<p>For atom type pairs I,J and I != J, if the sub-style assigned to I,I
|
|
and J,J is the same, and if the sub-style allows for mixing, then the
|
|
coefficients for I,J can be mixed. This means you do not have to
|
|
specify a pair_coeff command for I,J since the I,J type pair will be
|
|
assigned automatically to the sub-style defined for both I,I and J,J
|
|
and its coefficients generated by the mixing rule used by that
|
|
sub-style. For the <em>hybrid/overlay</em> style, there is an additional
|
|
requirement that both the I,I and J,J pairs are assigned to a single
|
|
sub-style. See the “pair_modify” command for details of mixing rules.
|
|
See the See the doc page for the sub-style to see if allows for
|
|
mixing.</p>
|
|
<p>The hybrid pair styles supports the <a class="reference internal" href="pair_modify.html"><em>pair_modify</em></a>
|
|
shift, table, and tail options for an I,J pair interaction, if the
|
|
associated sub-style supports it.</p>
|
|
<p>For the hybrid pair styles, the list of sub-styles and their
|
|
respective settings are written to <a class="reference internal" href="restart.html"><em>binary restart files</em></a>, so a <a class="reference internal" href="pair_style.html"><em>pair_style</em></a> command does
|
|
not need to specified in an input script that reads a restart file.
|
|
However, the coefficient information is not stored in the restart
|
|
file. Thus, pair_coeff commands need to be re-specified in the
|
|
restart input script.</p>
|
|
<p>These pair styles support the use of the <em>inner</em>, <em>middle</em>, and
|
|
<em>outer</em> keywords of the <a class="reference internal" href="run_style.html"><em>run_style respa</em></a> command, if
|
|
their sub-styles do.</p>
|
|
</div>
|
|
<div class="section" id="restrictions">
|
|
<h2>Restrictions<a class="headerlink" href="#restrictions" title="Permalink to this headline">¶</a></h2>
|
|
<p>When using a long-range Coulombic solver (via the
|
|
<a class="reference internal" href="kspace_style.html"><em>kspace_style</em></a> command) with a hybrid pair_style,
|
|
one or more sub-styles will be of the “long” variety,
|
|
e.g. <em>lj/cut/coul/long</em> or <em>buck/coul/long</em>. You must insure that the
|
|
short-range Coulombic cutoff used by each of these long pair styles is
|
|
the same or else LAMMPS will generate an error.</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="pair_coeff.html"><em>pair_coeff</em></a></p>
|
|
<p><strong>Default:</strong> none</p>
|
|
</div>
|
|
</div>
|
|
|
|
|
|
</div>
|
|
</div>
|
|
<footer>
|
|
|
|
|
|
<hr/>
|
|
|
|
<div role="contentinfo">
|
|
<p>
|
|
© Copyright .
|
|
</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 May 2015 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> |