"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)

:line

restart command :h3

[Syntax:]

restart 0
restart N root
restart N file1 file2 :pre

N = write a restart file every this many timesteps
root = filename to which timestep # is appended
file1,file2 = two full filenames, toggle between them when writing file :ul

[Examples:]

restart 0
restart 1000 poly.restart
restart 1000 restart.*.equil
restart 10000 poly.%.1 poly.%.2 :pre

[Description:]

Write out a binary restart file every so many timesteps as a run
proceeds.  A value of 0 means do not write out restart files.  Using
one filename as an argument will create a series of filenames which
include the timestep in the filename.  Using two filenames will
produce only 2 restart files.  LAMMPS will toggle between the 2 names
as it writes successive restart files.

Similar to "dump"_dump.html files, the restart filename(s) can contain
two wild-card characters.  If a "*" appears in the filename, it is
replaced with the current timestep value.  This is only recognized
when a single filename is used (not when toggling back and forth).
Thus, the 3rd example above creates restart files as follows:
restart.1000.equil, restart.2000.equil, etc.  If a single filename is
used with no "*", then the timestep value is appended.  E.g. the 2nd
example above creates restart files as follows: poly.restart.1000,
poly.restart.2000, etc.

If a "%" character appears in the restart filename(s), then one file
is written for each processor and the "%" character is replaced with
the processor ID from 0 to P-1.  An additional file with the "%"
replaced by "base" is also written, which contains global information.
For example, the files written on step 1000 for filename restart.%
would be restart.base.1000, restart.0.1000, restart.1.1000, ...,
restart.P-1.1000.  This creates smaller files and can be a fast mode
of output and subsequent input on parallel machines that support
parallel I/O.

Restart files are written on timesteps that are a multiple of N but
not on the first timestep of a run or minimization.  A restart file is
not written on the last timestep of a run unless it is a multiple of
N.  A restart file is written on the last timestep of a minimization
if N > 0 and the minimization converges.

See the "read_restart"_read_restart.html command for information about
what is stored in a restart file.

Restart files can be read by a "read_restart"_read_restart.html
command to restart a simulation from a particular state.  Because the
file is binary (to enable exact restarts), it may not be readable on
another machine.  In this case, the "restart2data
program"_Section_tools.html#restart in the tools directory can be used
to convert a restart file to an ASCII data file.  Both the
read_restart command and restart2data tool can read in a restart file
that was written with the "%" character so that multiple files were
created.

[Restrictions:] none

[Related commands:]

"write_restart"_write_restart.html, "read_restart"_read_restart.html

[Default:]

restart 0 :pre
