forked from lijiext/lammps
87 lines
3.0 KiB
HTML
87 lines
3.0 KiB
HTML
<HTML>
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<CENTER><A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LAMMPS Documentation</A> - <A HREF = "Section_commands.html#comm">LAMMPS Commands</A>
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</CENTER>
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<HR>
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<H3>print command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>print string keyword value
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</PRE>
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<UL><LI>string = text string to print, which may contain variables
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<LI>zero or more keyword/value pairs may be appended
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<LI>keyword = <I>file</I> or <I>append</I> or <I>screen</I>
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<PRE> <I>file</I> value = filename
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<I>append</I> value = filename
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<I>screen</I> value = <I>yes</I> or <I>no</I>
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</PRE>
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>print "Done with equilibration" file info.dat
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print Vol=$v append info.dat screen no
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print "The system volume is now $v"
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print 'The system volume is now $v'
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print """
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System volume = $v
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System temperature = $t
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"""
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>Print a text string to the screen and logfile. The text string must
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be a single argument, so if it is one line but more than one word, it
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should be enclosed in single or double quotes. To generate multiple
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lines of output, the string can be enclosed in triple quotes, as in
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the last example above. If the text string contains variables, they
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will be evaluated and their current values printed.
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</P>
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<P>If the <I>file</I> or <I>append</I> keyword is used, a filename is specified to
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which the output will be written. If <I>file</I> is used, then the
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filename is overwritten if it already exists. If <I>append</I> is used,
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then the filename is appended to if it already exists, or created if
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it does not exist.
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</P>
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<P>If the <I>screen</I> keyword is used, output to the screen and logfile can
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be turned on or off as desired.
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</P>
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<P>If you want the print command to be executed multiple times (with
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changing variable values), there are 3 options. First, consider using
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the <A HREF = "fix_print.html">fix print</A> command, which will print a string
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periodically during a simulation. Second, the print command can be
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used as an argument to the <I>every</I> option of the <A HREF = "run.html">run</A>
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command. Third, the print command could appear in a section of the
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input script that is looped over (see the <A HREF = "jump.html">jump</A> and
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<A HREF = "next.html">next</A> commands).
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</P>
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<P>See the <A HREF = "variable.html">variable</A> command for a description of <I>equal</I>
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style variables which are typically the most useful ones to use with
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the print command. Equal-style variables can calculate formulas
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involving mathematical operations, atom properties, group properties,
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thermodynamic properties, global values calculated by a
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<A HREF = "compute.html">compute</A> or <A HREF = "fix.html">fix</A>, or references to other
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<A HREF = "variable.html">variables</A>.
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</P>
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<P><B>Restrictions:</B> none
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</P>
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<P><B>Related commands:</B>
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</P>
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<P><A HREF = "fix_print.html">fix print</A>, <A HREF = "variable.html">variable</A>
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</P>
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<P><B>Default:</B>
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</P>
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<P>The option defaults are no file output and screen = yes.
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</P>
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</HTML>
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