lammps/doc/fix_print.txt

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"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 :pre
ID, group-ID are documented in "fix"_fix.html command
print = style name of this fix command
N = print every N steps
string = text string to print with optional variable names :ul
[Examples:]
fix extra all print 100 "Coords of marker atom = $x $y $z" :pre
[Description:]
Print a text string to the screen and logfile every N steps during a
simulation run. This can be used for diagnostic purposes or even as a
debugging tool to monitor some quantity during a run. The text string
must be a single argument, so it should be enclosed in double quotes
if it is more than one word. If it contains variables ($a thru $z) 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.
Note that if {equal}-style variables are used in the print line which
contain "thermo_style custom"_thermo_style.html keywords for potential
energy such as pe, eng, evdwl, ebond, etc, they will only be
up-to-date on timesteps where thermodynamics are computed. Hence, if
you output thermodynamics every 100 steps, but issue a fix print
command with N = 2 that contains such a variable, the printed value
will only be current on timesteps that are a multiple of 100. This is
because the potential functions in LAMMPS (pairwise, bond, etc) only
compute energies on timesteps when thermodynamic output is being
performed.
[Restrictions:] none
[Related commands:]
"variable"_variable.html, "print"_print.html
[Default:] none