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lammps/doc/src/fix_smd_adjust_dt.txt
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fix_smd_adjust_dt.txt
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"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)
:line
fix smd/adjust_dt command :h3
[Syntax:]
fix ID group-ID smd/adjust_dt arg :pre
ID, group-ID are documented in "fix"_fix.html command :ulb,l
smd/adjust_dt = style name of this fix command :l
arg = {s_fact} :l
{s_fact} = safety factor :pre
:ule
[Examples:]
fix 1 all smd/adjust_dt 0.1 :pre
[Description:]
The fix calculates a new stable time increment for use with the SMD time integrators.
The stable time increment is based on multiple conditions. For the SPH pair styles, a
CFL criterion (Courant, Friedrichs & Lewy, 1928) is evaluated, which determines the the speed of
sound cannot propagate further than a typical spacing between particles within a single time step to ensure
no information is lost. For the contact pair styles, a linear analysis of the pair potential determines a
stable maximum time step.
This fix inquires the minimum stable time increment across all particles contained in the group for which this
fix is defined. An additional safety factor {s_fact} is applied to the time increment.
See "this PDF guide"_USER/smd/SMD_LAMMPS_userguide.pdf to use Smooth Mach Dynamics in LAMMPS.
[Restart, fix_modify, output, run start/stop, minimize info:]
Currently, no part of USER-SMD supports restarting nor minimization.
[Restrictions:]
This fix is part of the USER-SMD package. It is only enabled if
LAMMPS was built with that package. See the "Making LAMMPS"_Section_start.html#start_3
section for more info.
[Related commands:]
"smd/tlsph_dt"_compute_smd_tlsph_dt.html
[Default:] none
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