forked from lijiext/lammps
73 lines
2.3 KiB
Plaintext
73 lines
2.3 KiB
Plaintext
.. index:: timestep
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timestep command
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================
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Syntax
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""""""
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.. parsed-literal::
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timestep dt
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* dt = timestep size (time units)
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Examples
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""""""""
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.. parsed-literal::
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timestep 2.0
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timestep 0.003
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Description
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"""""""""""
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Set the timestep size for subsequent molecular dynamics simulations.
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See the :doc:`units <units>` command for the time units associated with
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each choice of units that LAMMPS supports.
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The default value for the timestep size also depends on the choice of
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units for the simulation; see the default values below.
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When the :doc:`run style <run_style>` is *respa*\ , dt is the timestep for
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the outer loop (largest) timestep.
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Restrictions
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""""""""""""
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none
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Related commands
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""""""""""""""""
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:doc:`fix dt/reset <fix_dt_reset>`, :doc:`run <run>`,
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:doc:`run_style <run_style>` respa, :doc:`units <units>`
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Default
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"""""""
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+--------------------------------+------------+-----------------------+
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| choice of :doc:`units <units>` | time units | default timestep size |
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+--------------------------------+------------+-----------------------+
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| lj | tau | 0.005 tau |
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+--------------------------------+------------+-----------------------+
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| real | fmsec | 1.0 fmsec |
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+--------------------------------+------------+-----------------------+
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| metal | psec | 0.001 psec |
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+--------------------------------+------------+-----------------------+
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| si | sec | 1.0e-8 sec (10 nsec) |
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+--------------------------------+------------+-----------------------+
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| cgs | sec | 1.0e-8 sec (10 nsec) |
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+--------------------------------+------------+-----------------------+
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| electron | fmsec | 0.001 fmsec |
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+--------------------------------+------------+-----------------------+
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| micro | usec | 2.0 usec |
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+--------------------------------+------------+-----------------------+
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| nano | nsec | 0.00045 nsec |
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+--------------------------------+------------+-----------------------+
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.. _lws: http://lammps.sandia.gov
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.. _ld: Manual.html
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.. _lc: Section_commands.html#comm
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