68 lines
2.2 KiB
ReStructuredText
68 lines
2.2 KiB
ReStructuredText
.. index:: timestep
|
|
|
|
timestep command
|
|
================
|
|
|
|
Syntax
|
|
""""""
|
|
|
|
.. parsed-literal::
|
|
|
|
timestep dt
|
|
|
|
* dt = timestep size (time units)
|
|
|
|
Examples
|
|
""""""""
|
|
|
|
.. code-block:: LAMMPS
|
|
|
|
timestep 2.0
|
|
timestep 0.003
|
|
|
|
Description
|
|
"""""""""""
|
|
|
|
Set the timestep size for subsequent molecular dynamics simulations.
|
|
See the :doc:`units <units>` command for the time units associated with
|
|
each choice of units that LAMMPS supports.
|
|
|
|
The default value for the timestep size also depends on the choice of
|
|
units for the simulation; see the default values below.
|
|
|
|
When the :doc:`run style <run_style>` is *respa*\ , dt is the timestep for
|
|
the outer loop (largest) timestep.
|
|
|
|
Restrictions
|
|
""""""""""""
|
|
none
|
|
|
|
Related commands
|
|
""""""""""""""""
|
|
|
|
:doc:`fix dt/reset <fix_dt_reset>`, :doc:`run <run>`,
|
|
:doc:`run_style <run_style>` respa, :doc:`units <units>`
|
|
|
|
Default
|
|
"""""""
|
|
|
|
+--------------------------------+---------------+-----------------------+
|
|
| choice of :doc:`units <units>` | time units | default timestep size |
|
|
+--------------------------------+---------------+-----------------------+
|
|
| lj | :math:`\tau` | 0.005 :math:`\tau` |
|
|
+--------------------------------+---------------+-----------------------+
|
|
| real | fs | 1.0 fs |
|
|
+--------------------------------+---------------+-----------------------+
|
|
| metal | ps | 0.001 ps |
|
|
+--------------------------------+---------------+-----------------------+
|
|
| si | s | 1.0e-8 s (10 ns) |
|
|
+--------------------------------+---------------+-----------------------+
|
|
| cgs | s | 1.0e-8 s (10 ns) |
|
|
+--------------------------------+---------------+-----------------------+
|
|
| electron | fs | 0.001 fs |
|
|
+--------------------------------+---------------+-----------------------+
|
|
| micro | :math:`\mu`\ s| 2.0 :math:`\mu`\ s |
|
|
+--------------------------------+---------------+-----------------------+
|
|
| nano | ns | 0.00045 ns |
|
|
+--------------------------------+---------------+-----------------------+
|