2007-11-02 00:46:50 +08:00
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"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 pe command :h3
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[Syntax:]
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compute ID group-ID pe keyword ... :pre
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ID, group-ID are documented in "compute"_compute.html command
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pe = style name of this compute command
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2007-11-03 05:05:48 +08:00
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zero or more keywords may be appended
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2007-11-02 00:46:50 +08:00
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keyword = {pair} or {bond} or {angle} or {dihedral} or {improper} or {kspace} :ul
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[Examples:]
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compute 1 all pe
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2007-12-01 07:16:45 +08:00
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compute molPE all pe bond angle dihedral improper :pre
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2007-11-02 00:46:50 +08:00
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[Description:]
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Define a computation that calculates the potential energy of the
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entire system of atoms. The specified group must be "all". See the
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2007-12-01 07:16:45 +08:00
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"compute pe/atom"_compute_pe_atom.html command if you want per-atom
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2007-11-02 00:46:50 +08:00
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energies. These per-atom values could be summed for a group of atoms
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2008-02-26 00:06:38 +08:00
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via the "compute reduce"_compute_reduce.html command.
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2007-11-02 00:46:50 +08:00
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2008-03-01 09:13:20 +08:00
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The energy is calculated by the various pair, bond, etc potentials
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2007-11-02 00:46:50 +08:00
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defined for the simulation. If no extra keywords are listed, then the
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potential energy is the sum of pair, bond, angle, dihedral, improper,
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and kspace (long-range) energy. If any extra keywords are listed,
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then only those components are summed to compute the potential energy.
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Various fixes can contribute to the total potential energy of the
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system. See the doc pages for "individual fixes"_fix.html for
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details. The {thermo} option of the
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"compute_modify"_compute_modify.html command determines whether these
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contributions are added into the computed potential energy. If no
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keywords are specified the default is {yes}. If any keywords are
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specified, the default is {no}.
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A compute of this style with the ID of "thermo_pe" is created when
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LAMMPS starts up, as if this command were in the input script:
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compute thermo_pe all pe :pre
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See the "thermo_style" command for more details.
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2008-01-03 03:25:15 +08:00
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[Output info:]
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2009-12-04 07:58:11 +08:00
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This compute calculates a global scalar (the potential energy). This
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value can be used by any command that uses a global scalar value from
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a compute as input. See "this section"_Section_howto.html#4_15 for an
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overview of LAMMPS output options.
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2008-01-03 03:25:15 +08:00
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The scalar value calculated by this compute is "extensive", meaning it
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it scales with the number of atoms in the simulation.
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2010-01-24 07:20:05 +08:00
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The scalar value will be in energy "units"_units.html.
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2007-11-02 00:46:50 +08:00
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[Restrictions:] none
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2007-12-01 07:16:45 +08:00
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[Related commands:]
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"compute pe/atom"_compute_pe_atom.html
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2007-11-02 00:46:50 +08:00
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[Default:] none
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