forked from lijiext/lammps
51 lines
1.5 KiB
Plaintext
51 lines
1.5 KiB
Plaintext
"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
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:link(lws,http://lammps.sandia.gov)
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:link(ld,Manual.html)
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:link(lc,Section_commands.html#comm)
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:line
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compute variable command :h3
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[Syntax:]
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compute ID group-ID variable name :pre
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ID, group-ID are documented in "compute"_compute.html command
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variable/atom = style name of this compute command
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name = variable name to invoke to compute a scalar quantity :ul
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[Examples:]
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compute 1 all variable myTemp :pre
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[Description:]
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Define a computation that calculates a formula that returns a scalar
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quantity. This quantity can be time averaged and output via the "fix
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ave/time"_fix_ave_time.html command. It could also be output via the
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"thermo_style custom"_thermo_style.html command, although it makes
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more sense to access the variable directly in this case.
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The formula is defined by the "variable equal"_variable.html command.
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A variable of style {equal} can access properties of the system, such
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as volume or temperature, and also reference individual atom
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attributes, such as its coordinates or velocity.
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For example, these 3 commands would time average the system density
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(assuming the volume fluctuates) temperature and output the average
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value periodically to the file den.profile:
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variable den equal div(atoms,vol)
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compute density all variable den
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fix 1 all ave/time 1 1000 density 0 den.profile :pre
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[Restrictions:] none
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[Related commands:]
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"fix ave/time"_fix_ave_time.html, "variable"_variable.html
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[Default:] none
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