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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@1627 f3b2605a-c512-4ea7-a41b-209d697bcdaa

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sjplimp
2008-03-18 22:21:46 +00:00
parent e280d54724
commit cd92c5fb0c
10 changed files with 442 additions and 51 deletions
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30
doc/fix_nph.html
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@ -56,8 +56,8 @@ barostat <A HREF = "#Hoover">(Hoover)</A>, implemented as described in
<A HREF = "#Melchionna">(Melchionna)</A>. P is pressure. This creates a system
trajectory consistent with the isobaric ensemble. Unlike <A HREF = "fix_npt.html">fix
npt</A>, temperature will not be controlled if no other fix
is used. Temperature can be controlled independently by using "<A HREF = "fix_langevin.html">fix
langevin</A> or <A HREF = "fix_temp_rescale.html">fix
is used. Temperature can be controlled independently by using a
thermostatting fis such as <A HREF = "fix_langevin.html">fix langevin</A> or <A HREF = "fix_temp_rescale.html">fix
temp/rescale</A>.
</P>
<P>The atoms in the fix group are the only ones whose velocities and
@ -72,6 +72,15 @@ only the atoms in the fix group are re-scaled. The latter can be
useful for leaving the coordinates of atoms in a solid substrate
unchanged and controlling the pressure of a surrounding fluid.
</P>
<P>IMPORTANT NOTE: Unlike the <A HREF = "fix_press_berendsen.html">fix
press/berendsen</A> command which performs
barostatting but NO time integration, this fix performs barostatting
AND time integration. Thus you should not use any other time
integration fix, such as <A HREF = "fix_nve.html">fix nve</A> or <A HREF = "fix_nvt.html">fix
nvt</A> on atoms to which this fix is applied. Use <A HREF = "fix_npt.html">fix
npt</A> instead of this fix, if you want to control both
temperature and pressure via Nose/Hoover.
</P>
<HR>
<P>The pressure can be controlled in one of several styles, as specified
@ -112,14 +121,13 @@ Typically a value between 0.2 to 2.0 is sufficient to damp
oscillations after a few periods.
</P>
<P>For all pressure styles, the simulation box stays rectangular in
shape. Parinello-Rahman boundary conditions (tilted box) are not
implemented in LAMMPS.
shape. Parinello-Rahman boundary conditions (tilted box) for this fix
are not yet implemented in LAMMPS.
</P>
<P>For all styles, the <I>Pdamp</I> parameter operates like the <I>Tdamp</I>
parameter, determining the time scale on which pressure is relaxed.
For example, a value of 1000.0 means to relax the pressure in a
timespan of (roughly) 1000 time units (tau or fmsec or psec - see the
<A HREF = "units.html">units</A> command).
<P>For all styles, the <I>Pdamp</I> parameter determines the time scale on
which pressure is relaxed. For example, a value of 1000.0 means to
relax the pressure in a timespan of (roughly) 1000 time units (tau or
fmsec or psec - see the <A HREF = "units.html">units</A> command).
</P>
<HR>
@ -187,10 +195,6 @@ the simulation.
dimension whose target pressures are specified as NULL can be
non-periodic or periodic.
</P>
<P>You should not use <A HREF = "fix_nvt.html">fix nvt</A> with this fix. Instead, use
<A HREF = "fix_npt.html">fix npt</A> if you want to control both temperature and
pressure via Nose/Hoover.
</P>
<P><B>Related commands:</B>
</P>
<P><A HREF = "fix_nve.html">fix nve</A>, <A HREF = "fix_npt.html">fix npt</A>,