lammps/doc/fix_print.txt

"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

fix print command :h3

[Syntax:]

fix ID group-ID print N string keyword value ... :pre

ID, group-ID are documented in "fix"_fix.html command :ulb,l
print = style name of this fix command :l
N = print every N steps :l
string = text string to print with optional variable names :l
zero or more keyword/value pairs may be appended :l
keyword = {file} or {screen} :l
  {file} value = filename
  {screen} value = {yes} or {no} :pre
:ule

[Examples:]

fix extra all print 100 "Coords of marker atom = $x $y $z"
fix extra all print 100 "Coords of marker atom = $x $y $z" file coord.txt :pre

[Description:]

Print a text string every N steps during a simulation run.  This can
be used for diagnostic purposes or as a debugging tool to monitor some
quantity during a run.  The text string must be a single argument, so
it should be enclosed in double quotes if it is more than one word.
If it contains variables it must be enclosed in double quotes to
insure they are not evaluated when the input script is read, but will
instead be evaluated when the string is printed.

See the "variable"_variable.html command for a description of {equal}
style variables which are the most useful ones to use with the fix
print command, since they are evaluated afresh each timestep that the
fix print line is output.  Equal-style variables can calculate
formulas involving mathematical operations, atom properties, group
properties, thermodyanimc properties, global values calculated by a
"compute"_compute.html or "fix"_fix.html, or references to other
"variables"_variable.html.

If the {file} keyword is used, a filename is specified to which the
output generated by this fix will be written.

If the {screen} keyword is used, output by this fix to the screen and
logfile can be turned on or off as desired.

[Restart, fix_modify, output, run start/stop, minimize info:]

No information about this fix is written to "binary restart
files"_restart.html.  None of the "fix_modify"_fix_modify.html options
are relevant to this fix.  No global scalar or vector or per-atom
quantities are stored by this fix for access by various "output
commands"_Section_howto.html#4_15.  No parameter of this fix can be
used with the {start/stop} keywords of the "run"_run.html command.
This fix is not invoked during "energy minimization"_minimize.html.

[Restrictions:] none

[Related commands:]

"variable"_variable.html, "print"_print.html

[Default:]

The option defaults are no file output and screen = yes.