forked from lijiext/lammps
64 lines
1.9 KiB
Plaintext
64 lines
1.9 KiB
Plaintext
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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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mass command :h3
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[Syntax:]
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mass I value :pre
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I = atom type (see asterik form below)
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value = mass :ul
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[Examples:]
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mass 1 1.0
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mass * 62.5
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mass 2* 62.5 :pre
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[Description:]
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Set the mass for all atoms of one or more atom types. Mass values can
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also be set in the "read_data"_read_data.html data file. See the
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"units"_units.html command for what mass units to use.
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I can be specified in one of two ways. An explicit numeric value can
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be used, as in the 1st example above. Or a wild-card asterik can be
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used to set the mass for multiple atom types. This takes the form "*"
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or "*n" or "n*" or "m*n". If N = the number of atom types, then an
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asterik with no numeric values means all types from 1 to N. A leading
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asterik means all types from 1 to n (inclusive). A trailing asterik
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means all types from n to N (inclusive). A middle asterik means all
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types from m to n (inclusive).
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A line in a data file that specifies mass uses the exact same format
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as the arguments of the mass command in an input script, except that
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no wild-card asterik can be used. For example, under the "Masses"
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section of a data file, the line that corresponds to the 1st example
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above would be listed as
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1 1.0 :pre
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[Restrictions:]
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This command must come after the simulation box is defined by a
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"read_data"_read_data.html, "read_restart"_read_restart.html, or
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"create_box"_create_box.html command.
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All masses must be defined before a simulation is run (if the atom
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style requires masses be set). They must also all be defined before a
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"velocity"_velocity.html or "fix shake"_fix_shake.html command is
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used.
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Masses are not set for atom style granular. This is because each atom
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is assigned an individual mass in the data or restart file.
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[Related commands:] none
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[Default:] none
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