2011-10-27 00:59:49 +08:00
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<CENTER><A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LAMMPS Documentation</A> - <A HREF = "Section_commands.html#comm">LAMMPS Commands</A>
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<HR>
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<H3>pair_style brownian command
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</H3>
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2012-01-07 01:38:57 +08:00
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<H3>pair_style brownian/omp command
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</H3>
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2011-10-27 00:59:49 +08:00
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<H3>pair_style brownian/poly command
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</H3>
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2012-01-07 01:38:57 +08:00
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<H3>pair_style brownian/poly/omp command
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</H3>
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2011-10-27 00:59:49 +08:00
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<P><B>Syntax:</B>
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</P>
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2012-05-24 01:47:58 +08:00
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<PRE>pair_style style mu flaglog flagfld cutinner cutoff t_target seed flagHI flagVF
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2011-10-27 00:59:49 +08:00
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</PRE>
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<UL><LI>style = <I>brownian</I> or <I>brownian/poly</I>
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<LI>mu = dynamic viscosity (dynamic viscosity units)
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<LI>flaglog = 0/1 log terms in the lubrication approximation on/off
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<LI>flagfld = 0/1 to include/exclude Fast Lubrication Dynamics effects
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<LI>cutinner = inner cutoff distance (distance units)
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<LI>cutoff = outer cutoff for interactions (distance units)
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<LI>t_target = target temp of the system (temperature units)
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2012-05-24 01:47:58 +08:00
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<LI>seed = seed for the random number generator (positive integer)
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<LI>flagHI (optional) = 0/1 to include/exclude 1/r hydrodynamic interactions
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<LI>flagVF (optional) = 0/1 to include/exclude volume fraction corrections in the long-range isotropic terms
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2011-10-27 00:59:49 +08:00
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</UL>
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<P><B>Examples:</B>
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</P>
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2012-05-24 01:47:58 +08:00
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<PRE>pair_style brownian 1.5 1 1 2.01 2.5 2.0 5878567 (assuming radius = 1)
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2011-10-27 00:59:49 +08:00
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pair_coeff 1 1 2.05 2.8
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pair_coeff * *
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>Styles <I>brownian</I> and <I>brownain/poly</I> compute Brownian forces and
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torques on finite-size particles. The former requires monodisperse
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spherical particles; the latter allows for polydisperse spherical
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particles.
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</P>
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<P>These pair styles are designed to be used with either the <A HREF = "pair_lubricate.html">pair_style
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lubricate</A> or <A HREF = "pair_lubricateU.html">pair_style
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lubricateU</A> commands to provide thermostatting
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when dissipative lubrication forces are acting. Thus the parameters
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<I>mu</I>, <I>flaglog</I>, <I>flagfld</I>, <I>cutinner</I>, and <I>cutoff</I> should be
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specified consistent with the settings in the lubrication pair styles.
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For details, refer to either of the lubrication pair styles.
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</P>
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<P>The <I>t_target</I> setting is used to specify the target temperature of
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the system. The random number <I>seed</I> is used to generate random
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numbers for the thermostatting procedure.
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</P>
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2012-05-24 01:47:58 +08:00
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<P>The <I>flagHI</I> and <I>flagVF</I> settings are optional. Neither should be
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used, or both must be defined.
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</P>
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<HR>
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2011-10-27 00:59:49 +08:00
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<P>The following coefficients must be defined for each pair of atoms
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types via the <A HREF = "pair_coeff.html">pair_coeff</A> command as in the examples
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above, or in the data file or restart files read by the
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<A HREF = "read_data.html">read_data</A> or <A HREF = "read_restart.html">read_restart</A>
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commands, or by mixing as described below:
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</P>
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<UL><LI>cutinner (distance units)
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<LI>cutoff (distance units)
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</UL>
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<P>The two coefficients are optional. If neither is specified, the two
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cutoffs specified in the pair_style command are used. Otherwise both
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must be specified.
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</P>
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<HR>
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2014-08-15 00:30:25 +08:00
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<P>Styles with a <I>cuda</I>, <I>gpu</I>, <I>intel</I>, <I>kk</I>, <I>omp</I>, or <I>opt</I> suffix are
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functionally the same as the corresponding style without the suffix.
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They have been optimized to run faster, depending on your available
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hardware, as discussed in <A HREF = "Section_accelerate.html">this section</A> of
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the manual. The accelerated styles take the same arguments and should
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produce the same results, except for round-off and precision issues.
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2012-01-07 01:38:57 +08:00
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</P>
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2014-08-15 00:30:25 +08:00
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<P>These accelerated styles are part of the USER-CUDA, GPU, USER-INTEL,
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KOKKOS, USER-OMP and OPT packages, respectively. They are only
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enabled if LAMMPS was built with those packages. See the <A HREF = "Section_start.html#start_3">Making
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LAMMPS</A> section for more info.
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2012-01-07 01:38:57 +08:00
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</P>
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<P>You can specify the accelerated styles explicitly in your input script
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2012-01-28 07:39:14 +08:00
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by including their suffix, or you can use the <A HREF = "Section_start.html#start_7">-suffix command-line
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2012-01-07 01:38:57 +08:00
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switch</A> when you invoke LAMMPS, or you can
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use the <A HREF = "suffix.html">suffix</A> command in your input script.
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</P>
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<P>See <A HREF = "Section_accelerate.html">this section</A> of the manual for more
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instructions on how to use the accelerated styles effectively.
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</P>
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<HR>
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2011-10-27 00:59:49 +08:00
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<P><B>Mixing, shift, table, tail correction, restart, rRESPA info</B>:
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</P>
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<P>For atom type pairs I,J and I != J, the two cutoff distances for this
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pair style can be mixed. The default mix value is <I>geometric</I>. See
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the "pair_modify" command for details.
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</P>
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<P>This pair style does not support the <A HREF = "pair_modify.html">pair_modify</A>
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shift option for the energy of the pair interaction.
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</P>
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<P>The <A HREF = "pair_modify.html">pair_modify</A> table option is not relevant
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for this pair style.
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</P>
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<P>This pair style does not support the <A HREF = "pair_modify.html">pair_modify</A>
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tail option for adding long-range tail corrections to energy and
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pressure.
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</P>
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<P>This pair style writes its information to <A HREF = "restart.html">binary restart
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files</A>, so pair_style and pair_coeff commands do not need
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to be specified in an input script that reads a restart file.
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</P>
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<P>This pair style can only be used via the <I>pair</I> keyword of the
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<A HREF = "run_style.html">run_style respa</A> command. It does not support the
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<I>inner</I>, <I>middle</I>, <I>outer</I> keywords.
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</P>
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<HR>
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<P><B>Restrictions:</B>
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</P>
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<P>These styles are part of the FLD package. They are only enabled if
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LAMMPS was built with that package. See the <A HREF = "Section_start.html#2_3">Making
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LAMMPS</A> section for more info.
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</P>
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<P>Only spherical monodisperse particles are allowed for pair_style
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brownian.
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</P>
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<P>Only spherical particles are allowed for pair_style brownian/poly.
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</P>
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<P><B>Related commands:</B>
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</P>
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<P><A HREF = "pair_coeff.html">pair_coeff</A>, <A HREF = "pair_lubricate.html">pair_style
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lubricate</A>, <A HREF = "pair_lubricateU.html">pair_style
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lubricateU</A>
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</P>
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2012-05-24 01:47:58 +08:00
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<P><B>Default:</B>
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</P>
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<P>The default settings for the optional args are flagHI = 1 and flagVF =
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1.
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2011-10-27 00:59:49 +08:00
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</P>
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</HTML>
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