forked from lijiext/lammps
92 lines
2.6 KiB
Plaintext
92 lines
2.6 KiB
Plaintext
.. index:: print
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print command
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=============
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Syntax
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""""""
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.. parsed-literal::
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print string keyword value
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* string = text string to print, which may contain variables
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* zero or more keyword/value pairs may be appended
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* keyword = *file* or *append* or *screen*
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.. parsed-literal::
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*file* value = filename
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*append* value = filename
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*screen* value = *yes* or *no*
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Examples
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""""""""
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.. parsed-literal::
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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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Description
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"""""""""""
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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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If the *file* or *append* keyword is used, a filename is specified to
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which the output will be written. If *file* is used, then the
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filename is overwritten if it already exists. If *append* 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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If the *screen* 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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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 :doc:`fix print <fix_print>` 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 *every* option of the :doc:`run <run>`
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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 :doc:`jump <jump>` and
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:doc:`next <next>` commands).
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See the :doc:`variable <variable>` command for a description of *equal*
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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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:doc:`compute <compute>` or :doc:`fix <fix>`, or references to other
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:doc:`variables <variable>`.
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Restrictions
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""""""""""""
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none
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Related commands
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""""""""""""""""
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:doc:`fix print <fix_print>`, :doc:`variable <variable>`
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Default
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"""""""
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The option defaults are no file output and screen = yes.
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.. _lws: http://lammps.sandia.gov
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.. _ld: Manual.html
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.. _lc: Section_commands.html#comm
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