"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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write_dump command :h3

[Syntax:]

write_dump group-ID style file dump-args modify dump_modify-args :pre

group-ID = ID of the group of atoms to be dumped :ulb,l
style = any of the supported "dump styles"_dump.html :l
file = name of file to write dump info to :l
dump-args = any additional args needed for a particular "dump style"_dump.html :l
modify = all args after this keyword are passed to "dump_modify"_dump_modify.html (optional) :l
dump-modify-args = args for "dump_modify"_dump_modify.html (optional) :l,ule

[Examples:]

write_dump all atom dump.atom
write_dump subgroup atom dump.run.bin
write_dump all custom dump.myforce.* id type x y vx fx
write_dump flow custom dump.%.myforce id type c_myF\[3\] v_ke modify sort id
write_dump all xyz system.xyz modify sort id elements O H 
write_dump all image snap*.jpg type type size 960 960 modify backcolor white
write_dump all image snap*.jpg element element &
   bond atom 0.3 shiny 0.1 ssao yes 6345 0.2 size 1600 1600  &
   modify backcolor white element C C O H N C C C O H H S O H :pre

[Description:]

Dump a single snapshot of atom quantities to one or more files for the
current state of the system.  This is a one-time immediate operation,
in contrast to the "dump"_dump.html command which will will set up a
dump style to write out snapshots periodically during a running
simulation.

The syntax for this command is mostly identical to that of the
"dump"_dump.html and "dump_modify"_dump_modify.html commands as if
they were concatenated together, with the following exceptions: There
is no need for a dump ID or dump frequency and the keyword {modify} is
added.  The latter is so that the full range of
"dump_modify"_dump_modify.html options can be specified for the single
snapshot, just as they can be for multiple snapshots.  The {modify}
keyword separates the arguments that would normally be passed to the
{dump} command from those that would be given the {dump_modify}.  Both
support optional arguments and thus LAMMPS needs to be able to cleanly
separate the two sets of args.

Note that if the specified filename uses wildcard characters "*" or
"%", as supported by the "dump"_dump.html commmand, they will operate
in the same fashion to create the new filename(s).  Normally, "dump
image"_dump_image.html files require a filename with a "*" character
for the timestep.  That is not the case for the write_dump command; no
wildcard "*" character is necessary.

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[Restrictions:]

All restrictions for the "dump"_dump.html and
"dump_modify"_dump_modify.html commands apply to this command as well,
with the exception of the "dump image"_dump_image.html filename not
requiring a wildcard "*" character, as noted above.

Since dumps are normally written during a "run"_run.html or "energy
minimization"_minimize.html, the simulation has to be ready to run
before this command can be used.  Similarly, if the dump requires
information from a compute, fix, or variable, the information needs to
have been calculated for the current timestep (e.g. by a prior run),
else LAMMPS will generate an error message.

For example, it is not possible to dump per-atom energy with this
command before a run has been performed, since no energies and forces
have yet been calculated.  See the "variable"_variable.html doc page
sectinn on Variable Accuracy for more information on this topic.

[Related commands:]

"dump"_dump.html, "dump image"_dump_image.html,
"dump_modify"_dump_modify.html

[Default:]

The defaults are listed on the doc pages for the "dump"_dump.html and
"dump image"_dump_image.html and "dump_modify"_dump_modify.html
commands.