2015-07-30 22:38:28 +08:00
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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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2006-09-22 00:22:34 +08:00
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2015-07-30 22:38:28 +08:00
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<HR>
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2006-09-22 00:22:34 +08:00
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2015-07-30 22:38:28 +08:00
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<H3>compute_modify command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>compute_modify compute-ID keyword value ...
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</PRE>
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<UL><LI>compute-ID = ID of the compute to modify
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2006-09-22 00:22:34 +08:00
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<LI>one or more keyword/value pairs may be listed
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2006-09-22 00:22:34 +08:00
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2015-07-30 22:38:28 +08:00
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<LI>keyword = <I>extra</I> or <I>dynamic</I>
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<PRE> <I>extra</I> value = N
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2006-12-13 08:37:25 +08:00
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N = # of extra degrees of freedom to subtract
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<I>dynamic</I> value = <I>yes</I> or <I>no</I>
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2007-11-02 00:46:50 +08:00
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yes/no = do or do not recompute the number of atoms contributing to the temperature
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2015-07-30 22:38:28 +08:00
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<I>thermo</I> value = <I>yes</I> or <I>no</I>
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yes/no = do or do not add contributions from fixes to the potential energy
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</PRE>
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>compute_modify myTemp extra 0
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compute_modify newtemp dynamic yes extra 600
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>Modify one or more parameters of a previously defined compute. Not
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all compute styles support all parameters.
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</P>
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<P>The <I>extra</I> keyword refers to how many degrees-of-freedom are
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2007-02-10 05:40:32 +08:00
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subtracted (typically from 3N) as a normalizing factor in a
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temperature computation. Only computes that compute a temperature use
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2015-07-30 22:38:28 +08:00
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this option. The default is 2 or 3 for <A HREF = "dimension.html">2d or 3d
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systems</A> which is a correction factor for an ensemble
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2009-07-02 22:39:37 +08:00
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of velocities with zero total linear momentum. You can use a negative
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number for the <I>extra</I> parameter if you need to add
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degrees-of-freedom. See the <A HREF = "compute_temp_asphere.html">compute
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temp/asphere</A> command for an example.
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</P>
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<P>The <I>dynamic</I> keyword determines whether the number of atoms N in the
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2007-02-10 05:40:32 +08:00
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compute group is re-computed each time a temperature is computed.
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Only compute styles that compute a temperature use this option. By
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default, N is assumed to be constant. If you are adding atoms to the
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2015-07-30 22:38:28 +08:00
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system (see the <A HREF = "fix_pour.html">fix pour</A> or <A HREF = "fix_deposit.html">fix
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deposit</A> commands) or expect atoms to be lost
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2014-05-02 23:34:15 +08:00
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(e.g. due to evaporation), then this option should be used to insure
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the temperature is correctly normalized.
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</P>
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<P>The <I>thermo</I> keyword determines whether the potential energy
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contribution calculated by some <A HREF = "fix.html">fixes</A> is added to the
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2009-04-02 06:25:09 +08:00
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potential energy calculated by the compute. Currently, only the
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2015-07-30 22:38:28 +08:00
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compute of style <I>pe</I> uses this option. See the doc pages for
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<A HREF = "fix.html">individual fixes</A> for details.
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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 = "compute.html">compute</A>
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</P>
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<P><B>Default:</B>
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</P>
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<P>The option defaults are extra = 2 or 3 for 2d or 3d systems and
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dynamic = no. Thermo is <I>yes</I> if the compute of style <I>pe</I> was
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defined with no extra keywords; otherwise it is <I>no</I>.
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</P>
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</HTML>
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