forked from lijiext/lammps
60 lines
1.9 KiB
Plaintext
60 lines
1.9 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 ke command :h3
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[Syntax:]
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compute ID group-ID ke :pre
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ID, group-ID are documented in "compute"_compute.html command
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ke = style name of this compute command :ul
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[Examples:]
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compute 1 all ke :pre
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[Description:]
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Define a computation that calculates the translational kinetic energy
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of a group of particles.
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The kinetic energy or each particle is computed as 1/2 m v^2, where m
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and v are the mass and velocity of the particle.
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There is a subtle difference between the quantity calculated by this
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compute and the kinetic energy calculated by the {ke} or {etotal}
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keyword used in thermodynamic output, as specified by the
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"thermo_style"_thermo_style.html command. For this compute, kinetic
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energy is "translational" kinetic energy, calculated by the simple
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formula above. For thermodynamic output, the {ke} keyword infers
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kinetic energy from the temperature of the system with 1/2 Kb T of
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energy for each degree of freedom. For the default temperature
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computation via the "compute temp"_compute_temp.html command, these
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are the same. But different computes that calculate temperature can
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subtract out different non-thermal components of velocity and/or
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include different degrees of freedom (translational, rotational, etc).
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[Output info:]
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This compute calculates a global scalar (the KE). This value can be
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used by any command that uses a global scalar value from a compute as
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input. See "this section"_Section_howto.html#4_15 for an overview of
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LAMMPS output options.
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The scalar value calculated by this compute is "extensive". The
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scalar value will be in energy "units"_units.html.
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[Restrictions:] none
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[Related commands:]
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"compute erotate/sphere"_compute_erotate_sphere.html
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[Default:] none
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