"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 dpd/energy command :h3
fix dpd/energy/kk command :h3

[Syntax:]

fix ID group-ID dpd/energy :pre

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

[Examples:]

fix 1 all dpd/energy :pre

[Description:]

Perform constant energy dissipative particle dynamics (DPD-E)
integration.  This fix updates the internal energies for particles in
the group at each timestep.  It must be used in conjunction with a
deterministic integrator (e.g. "fix nve"_fix_nve.html) that updates
the particle positions and velocities.

For fix {dpd/energy}, the particle internal temperature is related to
the particle internal energy through a mesoparticle equation of state.
An additional fix must be specified that defines the equation of state
for each particle, e.g. "fix eos/cv"_fix_eos_cv.html.

This fix must be used with the "pair_style
dpd/fdt/energy"_pair_style.html command.

Note that numerous variants of DPD can be specified by choosing an
appropriate combination of the integrator and "pair_style
dpd/fdt/energy"_pair_style.html command.  DPD under isoenergetic conditions
can be specified by using fix {dpd/energy}, fix {nve} and pair_style
{dpd/fdt/energy}.  DPD under isoenthalpic conditions can
be specified by using fix {dpd/energy}, 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 must be used with an additional fix that specifies time
integration, e.g. "fix nve"_fix_nve.html.

The fix {dpd/energy} requires the {dpd} "atom_style"_atom_style.html
to be used in order to properly account for the particle internal
energies and temperature.

The fix {dpd/energy} must be used with an additional fix that specifies the
mesoparticle equation of state for each particle.

[Related commands:]

"fix nve"_fix_nve.html "fix eos/cv"_fix_eos_cv.html

[Default:] none

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:link(Lisal1)
[(Lisal)] M. Lisal, J.K. Brennan, J. Bonet Avalos, "Dissipative
particle dynamics at isothermal, isobaric, isoenergetic, and
isoenthalpic conditions using Shardlow-like splitting algorithms.",
J. Chem. Phys., 135, 204105 (2011).

:link(Larentzos3)
[(Larentzos)] 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).
