jianmu
/
lammps
forked from lijiext/lammps
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@3033 f3b2605a-c512-4ea7-a41b-209d697bcdaa

This commit is contained in:
sjplimp 2009-08-08 22:59:06 +00:00
parent 631f5b5f63
commit 15b6eeb011
2 changed files with 50 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
doc/fix_langevin.html
View File

@ -27,10 +27,13 @@
<LI>zero or more keyword/value pairs may be appended
<PRE>keyword = <I>scale</I>
<PRE>keyword = <I>scale</I> or <I>tally</I>
<I>scale</I> values = type ratio
type = atom type (1-N)
ratio = factor by which to scale the damping coefficient
ratio = factor by which to scale the damping coefficient
<I>tally</I> values = <I>no</I> or <I>yes</I>
<I>no</I> = do not tally the energy added/subtracted to atoms
<I>yes</I> = do tally the energy added/subtracted to atoms
</PRE>
</UL>
@ -139,6 +142,13 @@ particle mass in Ff, unlike fix <I>viscous</I>. Thus the mass and size of
different atom types should be accounted for in the choice of ratio
values.
</P>
<P>The keyword <I>tally</I> enables the calculation of the cummulative energy
added/subtracted to the atoms as they are thermostatted. Effectively
it is the energy exchanged between the infinite thermal reservoir and
the particles. As described below, this energy can then be printed
out or added to the potential energy of the system to monitor energy
conservation.
</P>
<P><B>Restart, fix_modify, output, run start/stop, minimize info:</B>
</P>
<P>No information about this fix is written to <A HREF = "restart.html">binary restart
@ -154,8 +164,18 @@ you have defined to this fix which will be used in its thermostatting
procedure, as described above. For consistency, the group used by
this fix and by the compute should be the same.
</P>
<P>No global scalar or vector or per-atom quantities are stored by this
fix for access by various <A HREF = "Section_howto.html#4_15">output commands</A>.
<P>The <A HREF = "fix_modify.html">fix_modify</A> <I>energy</I> option is supported by this
fix to add the energy change induced by Langevin thermostatting to the
system's potential energy as part of <A HREF = "thermo_style.html">thermodynamic
output</A>. Note that use of this option requires
setting the <I>tally</I> keyword to <I>yes</I>.
</P>
<P>The cummulative energy change due to this fix is stored as a scalar
quantity, which can be accessed by various <A HREF = "Section_howto.html#4_15">output
commands</A>. The scalar value calculated by
this fix is "extensive", meaning it scales with the number of atoms in
the simulation. Note that use of this option requires setting the
<I>tally</I> keyword to <I>yes</I>.
</P>
<P>This fix can ramp its target temperature over multiple runs, using the
<I>start</I> and <I>stop</I> keywords of the <A HREF = "run.html">run</A> command. See the
@ -172,8 +192,7 @@ viscous</A>, <A HREF = "fix_nvt.html">fix nvt</A>
</P>
<P><B>Default:</B>
</P>
<P>The option defaults are axes = 1 1 1, scale = 1.0 for all types, no
region, and weight = 1.0.
<P>The option defaults are scale = 1.0 for all types and tally = no.
</P>
<HR>

32
doc/fix_langevin.txt
View File

@ -17,12 +17,14 @@ langevin = style name of this fix command :l
Tstart,Tstop = desired temperature at start/end of run (temperature units) :l
damp = damping parameter (time units) :l
seed = random number seed to use for white noise (positive integer) :l
zero or more keyword/value pairs may be appended :l
keyword = {scale}
keyword = {scale} or {tally}
{scale} values = type ratio
type = atom type (1-N)
ratio = factor by which to scale the damping coefficient :pre
ratio = factor by which to scale the damping coefficient
{tally} values = {no} or {yes}
{no} = do not tally the energy added/subtracted to atoms
{yes} = do tally the energy added/subtracted to atoms :pre
:ule
[Examples:]
@ -130,6 +132,13 @@ particle mass in Ff, unlike fix {viscous}. Thus the mass and size of
different atom types should be accounted for in the choice of ratio
values.
The keyword {tally} enables the calculation of the cummulative energy
added/subtracted to the atoms as they are thermostatted. Effectively
it is the energy exchanged between the infinite thermal reservoir and
the particles. As described below, this energy can then be printed
out or added to the potential energy of the system to monitor energy
conservation.
[Restart, fix_modify, output, run start/stop, minimize info:]
No information about this fix is written to "binary restart
@ -145,8 +154,18 @@ you have defined to this fix which will be used in its thermostatting
procedure, as described above. For consistency, the group used by
this fix and by the compute should be the same.
No global scalar or vector or per-atom quantities are stored by this
fix for access by various "output commands"_Section_howto.html#4_15.
The "fix_modify"_fix_modify.html {energy} option is supported by this
fix to add the energy change induced by Langevin thermostatting to the
system's potential energy as part of "thermodynamic
output"_thermo_style.html. Note that use of this option requires
setting the {tally} keyword to {yes}.
The cummulative energy change due to this fix is stored as a scalar
quantity, which can be accessed by various "output
commands"_Section_howto.html#4_15. The scalar value calculated by
this fix is "extensive", meaning it scales with the number of atoms in
the simulation. Note that use of this option requires setting the
{tally} keyword to {yes}.
This fix can ramp its target temperature over multiple runs, using the
{start} and {stop} keywords of the "run"_run.html command. See the
@ -163,8 +182,7 @@ viscous"_fix_viscous.html, "fix nvt"_fix_nvt.html
[Default:]
The option defaults are axes = 1 1 1, scale = 1.0 for all types, no
region, and weight = 1.0.
The option defaults are scale = 1.0 for all types and tally = no.
:line