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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@281 f3b2605a-c512-4ea7-a41b-209d697bcdaa

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sjplimp
2007-02-09 21:37:30 +00:00
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doc/fix_temp_rescale.html
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@ -15,26 +15,17 @@
</P>
<PRE>fix ID group-ID temp/rescale N Tstart Tstop window fraction keyword values ...
</PRE>
<UL><LI>ID, group-ID are documented in <A HREF = "fix.html">fix</A> command
<LI>temp/rescale = style name of this fix command
<UL><LI>ID, group-ID are documented in <A HREF = "fix.html">fix</A> command
<LI>temp/rescale = style name of this fix command
<LI>N = perform rescaling every N steps
<LI>Tstart,Tstop = desired temperature at start/end of run (temperature units)
<LI>window = only rescale if temperature is outside this window (temperature units)
<LI>fraction = rescale to target temperature by this fraction
<LI>zero or more keyword/value pairs may be appended to the args
<PRE>keyword = <I>region</I>
<I>region</I> values = region-ID
region-ID = ID of region to apply rescaling to
</PRE>
<LI>Tstart,Tstop = desired temperature at start/end of run (temperature units)
<LI>window = only rescale if temperature is outside this window (temperature units)
<LI>fraction = rescale to target temperature by this fraction
<LI>zero or more keyword/value pairs may be appended to the args
<LI>keyword = <I>region</I>
</UL>
<PRE> <I>region</I> values = region-ID of region to apply rescaling to
</PRE>
<P><B>Examples:</B>
</P>
<PRE>fix 3 flow temp/rescale 100 1.0 1.1 0.02 0.5
@ -61,43 +52,47 @@ value.
specified geometric region (and in the fix group). Since atoms can
enter/leave a region, this test is performed each timestep.
</P>
<P>This fix computes a temperature each timestep. The fix creates its
own method for computing T, as if it had been defined by one of these
commands:
</P>
<PRE>temperature fix-ID group-ID full
temperature fix-ID group-ID region region-ID
</PRE>
<P>Which is used depends on whether a region was specified with the fix.
See the <A HREF = "temperature.html">temperature</A> command for details. Note that
this is NOT the temperature with ID = <I>default</I>. This means you can
change the attributes of this fix's temperature (e.g. its
degrees-of-freedom) via the <A HREF = "temp_modify.html">temp_modify</A> command or
print the temperature with thermodyanmic output via the <A HREF = "thermo_style.html">thermo_style
custom</A> command using the appropriate temp-ID =
fix-ID. It also means that changing attributes of the default
temperature will have no effect on this fix. Alternatively, you can
directly assign a new temperature to the fix via the
<A HREF = "fix_modify.html">fix_modify</A> command. For consistency, if using the
keyword <I>region</I>, the temperature you assign should also be of style
<I>region</I>.
</P>
<P>A temp/rescale fix does not update the coordinates of its atoms. It
is normally used with a fix of style <I>nve</I> that does that. A
temp/rescale fix should not normally be used on atoms that also have
their temperature controlled by another fix - e.g. a
<A HREF = "fix_nvt.html">nvt</A> or <A HREF = "fix_langevin.html">langevin</A> fix.
</P>
<P>This fix supports the <A HREF = "fix_modify.html">fix_modify</A> options for
<I>thermo</I> and <I>energy</I>. The former will print the contribution the fix
makes to the energy of the system when thermodynamics is printed. The
latter will add this contribution to the total potential energy
(PotEng) so that energy conservation can be monitored. Note that the
energy value printed by thermo is not cummulative energy, but energy
added in the most recent rescaling. Also note that because this fix
is invoked every N steps and thermo may be printed every M steps, that
unless M is a multiple of N, the energy info printed by thermo will
not be for the current timestep.
<P>This fix computes a temperature each timestep. To do this, the fix
creates its own compute of style "temp" or "temp/region", as if one of
these commands had been issued:
</P>
<PRE>compute fix-ID_temp group-ID temp
compute fix-ID_temp group-ID temp/region region-ID
</PRE>
<P>Which is used depends on whether a region was specified with the fix.
See the <A HREF = "compute_temp.html">compute temp</A> and <A HREF = "compute_temp_region.html<A HREF = "temp"">>compute
temp/region</A> commands for details. Note that
the ID of the new compute is the fix-ID with </A> appended and the
group for the new compute is the same as the fix group.
</P>
<P>Note that this is NOT the compute used by thermodynamic output (see
the <A HREF = "thermo_style.html">thermo_style</A> command) with ID = <I>thermo_temp</I>.
This means you can change the attributes of this fix's temperature
(e.g. its degrees-of-freedom) via the
<A HREF = "compute_modify.html">compute_modify</A> command or print this temperature
during thermodyanmic output via the <A HREF = "thermo_style.html">thermo_style
custom</A> command using the appropriate compute-ID.
It also means that changing attributes of <I>thermo_temp</I> will have no
effect on this fix. Alternatively, you can directly assign a new
compute (for calculating temeperature) that you have defined to this
fix via the <A HREF = "fix_modify.html">fix_modify</A> command. For consistency, if
using the keyword <I>region</I>, the compute you assign should also be of
style <I>temp/region</I>.
</P>
<P>This fix makes a contribution to the potential energy of the system
that can be included in thermodynamic output of potential energy using
the <A HREF = "fix_modify.html">fix_modify energy</A> option. The contribution can
also be printed by itself via the keyword <I>f_fix-ID</I> in the
<A HREF = "thermo_style.html">thermo_style custom</A> command. Note that because
this fix is invoked every N steps and thermodynamic info may be
printed every M steps, that unless M is a multiple of N, the energy
info accessed will not be for the current timestep.
</P>
<P><B>Restrictions:</B> none
</P>