"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)

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fix shardlow command :h3
fix shardlow/kk command :h3

[Syntax:]

fix ID group-ID shardlow :pre

ID, group-ID are documented in "fix"_fix.html command
shardlow = style name of this fix command :ul

[Examples:]

fix 1 all shardlow :pre

[Description:]

Specifies that the Shardlow splitting algorithm (SSA) is to be used to
integrate the DPD equations of motion.  The SSA splits the integration
into a stochastic and deterministic integration step.  The fix
{shardlow} performs the stochastic integration step and must be used
in conjunction with a deterministic integrator (e.g. "fix
nve"_fix_nve.html or "fix nph"_fix_nh.html).  The stochastic
integration of the dissipative and random forces is performed prior to
the deterministic integration of the conservative force. Further
details regarding the method are provided in "(Lisal)"_#Lisal and
"(Larentzos1)"_#Larentzos1sh.

The fix {shardlow} must be used with the "pair_style
dpd/fdt"_pair_style.html or "pair_style
dpd/fdt/energy"_pair_style.html command to properly initialize the
fluctuation-dissipation theorem parameter(s) sigma (and kappa, if
necessary).

Note that numerous variants of DPD can be specified by choosing an
appropriate combination of the integrator and "pair_style
dpd/fdt"_pair_style.html command.  DPD under isothermal conditions can
be specified by using fix {shardlow}, fix {nve} and pair_style
{dpd/fdt}.  DPD under isoenergetic conditions can be specified by
using fix {shardlow}, fix {nve} and pair_style {dpd/fdt/energy}.  DPD
under isobaric conditions can be specified by using fix shardlow, fix
{nph} and pair_style {dpd/fdt}.  DPD under isoenthalpic conditions can
be specified by using fix shardlow, fix {nph} and pair_style
{dpd/fdt/energy}.  Examples of each DPD variant are provided in the
examples/USER/dpd directory.

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Styles with a {gpu}, {intel}, {kk}, {omp}, or {opt} 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 "Section 5"_Section_accelerate.html
of the manual.  The accelerated styles take the same arguments and
should produce the same results, except for round-off and precision
issues.

These accelerated styles are part of the GPU, USER-INTEL, KOKKOS,
USER-OMP and OPT packages, respectively.  They are only enabled if
LAMMPS was built with those packages.  See the "Making
LAMMPS"_Section_start.html#start_3 section for more info.

You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the "-suffix command-line
switch"_Section_start.html#start_6 when you invoke LAMMPS, or you can
use the "suffix"_suffix.html command in your input script.

See "Section 5"_Section_accelerate.html of the manual for
more instructions on how to use the accelerated styles effectively.

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[Restrictions:]

This command is part of the USER-DPD package.  It is only enabled if
LAMMPS was built with that package.  See the "Making
LAMMPS"_Section_start.html#start_3 section for more info.

This fix is currently limited to orthogonal simulation cell
geometries.

This fix must be used with an additional fix that specifies time
integration, e.g. "fix nve"_fix_nve.html or "fix nph"_fix_nh.html.

The Shardlow splitting algorithm requires the sizes of the sub-domain
lengths to be larger than twice the cutoff+skin.  Generally, the
domain decomposition is dependent on the number of processors
requested.

[Related commands:]

"pair_style dpd/fdt"_pair_dpd_fdt.html, "fix eos/cv"_fix_eos_cv.html

[Default:] none

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:link(Lisal)
[(Lisal)] M. Lisal, J.K. Brennan, J. Bonet Avalos, "Dissipative
particle dynamics as isothermal, isobaric, isoenergetic, and
isoenthalpic conditions using Shardlow-like splitting algorithms.",
J. Chem. Phys., 135, 204105 (2011).

:link(Larentzos1sh)
[(Larentzos1)] J.P. Larentzos, J.K. Brennan, J.D. Moore, M. Lisal and
W.D. Mattson, "Parallel Implementation of Isothermal and Isoenergetic
Dissipative Particle Dynamics Using Shardlow-Like Splitting
Algorithms", Comput. Phys. Commun., 185, 1987-1998 (2014).

:link(Larentzos2sh)
[(Larentzos2)] J.P. Larentzos, J.K. Brennan, J.D. Moore, and
W.D. Mattson, "LAMMPS Implementation of Constant Energy Dissipative
Particle Dynamics (DPD-E)", ARL-TR-6863, U.S. Army Research
Laboratory, Aberdeen Proving Ground, MD (2014).
