1.. index:: timestep 2 3timestep command 4================ 5 6Syntax 7"""""" 8 9.. parsed-literal:: 10 11 timestep dt 12 13* dt = timestep size (time units) 14 15Examples 16"""""""" 17 18.. code-block:: LAMMPS 19 20 timestep 2.0 21 timestep 0.003 22 23Description 24""""""""""" 25 26Set the timestep size for subsequent molecular dynamics simulations. 27See the :doc:`units <units>` command for the time units associated with 28each choice of units that LAMMPS supports. 29 30The default value for the timestep size also depends on the choice of 31units for the simulation; see the default values below. 32 33When the :doc:`run style <run_style>` is *respa*, dt is the timestep for 34the outer loop (largest) timestep. 35 36Restrictions 37"""""""""""" 38 none 39 40Related commands 41"""""""""""""""" 42 43:doc:`fix dt/reset <fix_dt_reset>`, :doc:`run <run>`, 44:doc:`run_style <run_style>` respa, :doc:`units <units>` 45 46Default 47""""""" 48 49+--------------------------------+---------------+-----------------------+ 50| choice of :doc:`units <units>` | time units | default timestep size | 51+--------------------------------+---------------+-----------------------+ 52| lj | :math:`\tau` | 0.005 :math:`\tau` | 53+--------------------------------+---------------+-----------------------+ 54| real | fs | 1.0 fs | 55+--------------------------------+---------------+-----------------------+ 56| metal | ps | 0.001 ps | 57+--------------------------------+---------------+-----------------------+ 58| si | s | 1.0e-8 s (10 ns) | 59+--------------------------------+---------------+-----------------------+ 60| cgs | s | 1.0e-8 s (10 ns) | 61+--------------------------------+---------------+-----------------------+ 62| electron | fs | 0.001 fs | 63+--------------------------------+---------------+-----------------------+ 64| micro | :math:`\mu`\ s| 2.0 :math:`\mu`\ s | 65+--------------------------------+---------------+-----------------------+ 66| nano | ns | 0.00045 ns | 67+--------------------------------+---------------+-----------------------+ 68