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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@14212 f3b2605a-c512-4ea7-a41b-209d697bcdaa
59 lines
1.9 KiB
HTML
59 lines
1.9 KiB
HTML
<HTML>
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<CENTER><A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LAMMPS Documentation</A> - <A HREF = "Section_commands.html#comm">LAMMPS Commands</A>
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</CENTER>
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<HR>
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<H3>timestep command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>timestep dt
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</PRE>
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<UL><LI>dt = timestep size (time units)
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>timestep 2.0
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timestep 0.003
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>Set the timestep size for subsequent molecular dynamics simulations.
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See the <A HREF = "units.html">units</A> command for the time units associated with
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each choice of units that LAMMPS supports.
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</P>
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<P>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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</P>
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<P>When the <A HREF = "run_style.html">run style</A> is <I>respa</I>, dt is the timestep for
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the outer loop (largest) timestep.
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</P>
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<P><B>Restrictions:</B> none
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</P>
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<P><B>Related commands:</B>
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</P>
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<P><A HREF = "fix_dt_reset.html">fix dt/reset</A>, <A HREF = "run.html">run</A>,
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<A HREF = "run_style.html">run_style</A> respa, <A HREF = "units.html">units</A>
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</P>
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<P><B>Default:</B>
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</P>
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<DIV ALIGN=left ><TABLE BORDER=1 >
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<TR ALIGN="center"><TD >choice of <A HREF = "units.html">units</A> </TD><TD > time units </TD><TD > default timestep size</TD></TR>
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<TR ALIGN="center"><TD >lj </TD><TD > tau </TD><TD > 0.005 tau</TD></TR>
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<TR ALIGN="center"><TD >real </TD><TD > fmsec </TD><TD > 1.0 fmsec</TD></TR>
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<TR ALIGN="center"><TD >metal </TD><TD > psec </TD><TD > 0.001 psec</TD></TR>
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<TR ALIGN="center"><TD >si </TD><TD > sec </TD><TD > 1.0e-8 sec (10 nsec)</TD></TR>
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<TR ALIGN="center"><TD >cgs </TD><TD > sec </TD><TD > 1.0e-8 sec (10 nsec)</TD></TR>
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<TR ALIGN="center"><TD >electron </TD><TD > fmsec </TD><TD > 0.001 fmsec</TD></TR>
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<TR ALIGN="center"><TD >micro </TD><TD > usec </TD><TD > 2.0 usec</TD></TR>
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<TR ALIGN="center"><TD >nano </TD><TD > nsec </TD><TD > 0.00045 nsec
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</TD></TR></TABLE></DIV>
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</HTML>
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