git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@5811 f3b2605a-c512-4ea7-a41b-209d697bcdaa

This commit is contained in:
sjplimp 2011-03-23 13:54:53 +00:00
parent 2ed6a60ace
commit 72289a2606
2 changed files with 26 additions and 0 deletions

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@ -82,6 +82,19 @@ re-scaled. This 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: Appling an external pressure to tilt dimensions <I>xy</I>,
<I>xz</I>, <I>yz</I> can sometimes result in arbitrarily large values of the
tilt dimensions, i.e. a dramatically deformed simulation box. This
typically indicates that there is something badly wrong with how the
simulation was constructed. The two most common sources of this error
are applying a shear stress to a liquid system or specifying an
external shear stress tensor that exceeds the yield stress of the
solid. In either case the minimization is either not going to
converge at all, or converge to a bogus conformation. Note that
LAMMPS will not throw an error when the tilt value becomes extreme,
but the final box may be unsuitable for running dynamics on, unless
fix deform is used first to remap the box to a valid tilt value.
</P>
<HR>
<P>The <I>couple</I> keyword allows two or three of the diagonal components of

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@ -76,6 +76,19 @@ re-scaled. This can be useful for leaving the coordinates of atoms in
a solid substrate unchanged and controlling the pressure of a
surrounding fluid.
IMPORTANT NOTE: Appling an external pressure to tilt dimensions {xy},
{xz}, {yz} can sometimes result in arbitrarily large values of the
tilt dimensions, i.e. a dramatically deformed simulation box. This
typically indicates that there is something badly wrong with how the
simulation was constructed. The two most common sources of this error
are applying a shear stress to a liquid system or specifying an
external shear stress tensor that exceeds the yield stress of the
solid. In either case the minimization is either not going to
converge at all, or converge to a bogus conformation. Note that
LAMMPS will not throw an error when the tilt value becomes extreme,
but the final box may be unsuitable for running dynamics on, unless
fix deform is used first to remap the box to a valid tilt value.
:line
The {couple} keyword allows two or three of the diagonal components of