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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@13322 f3b2605a-c512-4ea7-a41b-209d697bcdaa

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sjplimp
2015-03-27 20:40:30 +00:00
parent 8d1033f0d9
commit 48d0d2a7b6
2 changed files with 30 additions and 30 deletions
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30
doc/fix_temp_csvr.html
View File

@ -41,21 +41,21 @@
</P>
<P>Adjust the temperature with a canonical sampling thermostat that uses
global velocity rescaling with Hamiltonian dynamics (<I>temp/csvr</I>)
<A HREF = "#Bussi1">(Bussi1)</A>, or Langevin dynamics (<I>temp/csld</I>) <A HREF = "#Bussi2">(Bussi2)</A>.
In the case of <I>temp/csvr</I> the thermostat is similar to the empirical
Berendsen thermostat in <A HREF = "fix_temp_berendsen.html">temp/berendsen</A>, but
chooses the actual scaling factor from a suitably chosen (gaussian)
distribution rather than having it determined from the time constant
directly. In the second case the velocities are updated to a linear
combination of the current velocities with a gaussian distribution
of velocities at the desired temperature. Both termostats are applied
in every timestep.
<A HREF = "#Bussi1">(Bussi1)</A>, or Langevin dynamics (<I>temp/csld</I>)
<A HREF = "#Bussi2">(Bussi2)</A>. In the case of <I>temp/csvr</I> the thermostat is
similar to the empirical Berendsen thermostat in
<A HREF = "fix_temp_berendsen.html">temp/berendsen</A>, but chooses the actual
scaling factor from a suitably chosen (gaussian) distribution rather
than having it determined from the time constant directly. In the
second case the velocities are updated to a linear combination of the
current velocities with a gaussian distribution of velocities at the
desired temperature. Both termostats are applied in every timestep.
</P>
<P>The thermostat is applied to only the translational degrees of freedom
for the particles, which is an important consideration for finite-size
particles which have rotational degrees of freedom are being
thermostatted with these fixes. The translational degrees of freedom can
also have a bias velocity removed from them before thermostatting
thermostatted with these fixes. The translational degrees of freedom
can also have a bias velocity removed from them before thermostatting
takes place; see the description below.
</P>
<P>The desired temperature at each timestep is a ramped value during the
@ -78,10 +78,10 @@ time. Thus it is easy to specify a time-dependent temperature.
</P>
<P>IMPORTANT NOTE: Unlike the <A HREF = "fix_nh.html">fix nvt</A> command which
performs Nose/Hoover thermostatting AND time integration, these fixes
do NOT perform time integration. They only modify velocities to
effect thermostatting. Thus you must use a separate time integration
fix, like <A HREF = "fix_nve.html">fix nve</A> to actually update the positions of
atoms using the modified velocities. Likewise, these fixes should not
do NOT perform time integration. They only modify velocities to effect
thermostatting. Thus you must use a separate time integration fix,
like <A HREF = "fix_nve.html">fix nve</A> to actually update the positions of atoms
using the modified velocities. Likewise, these fixes should not
normally be used on atoms that also have their temperature controlled
by another fix - e.g. by <A HREF = "fix_nh.html">fix nvt</A> or <A HREF = "fix_langevin.html">fix
langevin</A> commands.

30
doc/fix_temp_csvr.txt
View File

@ -30,21 +30,21 @@ fix 1 all temp/csld 100.0 300.0 10.0 123321 :pre
Adjust the temperature with a canonical sampling thermostat that uses
global velocity rescaling with Hamiltonian dynamics ({temp/csvr})
"(Bussi1)"_#Bussi1, or Langevin dynamics ({temp/csld}) "(Bussi2)"_#Bussi2.
In the case of {temp/csvr} the thermostat is similar to the empirical
Berendsen thermostat in "temp/berendsen"_fix_temp_berendsen.html, but
chooses the actual scaling factor from a suitably chosen (gaussian)
distribution rather than having it determined from the time constant
directly. In the second case the velocities are updated to a linear
combination of the current velocities with a gaussian distribution
of velocities at the desired temperature. Both termostats are applied
in every timestep.
"(Bussi1)"_#Bussi1, or Langevin dynamics ({temp/csld})
"(Bussi2)"_#Bussi2. In the case of {temp/csvr} the thermostat is
similar to the empirical Berendsen thermostat in
"temp/berendsen"_fix_temp_berendsen.html, but chooses the actual
scaling factor from a suitably chosen (gaussian) distribution rather
than having it determined from the time constant directly. In the
second case the velocities are updated to a linear combination of the
current velocities with a gaussian distribution of velocities at the
desired temperature. Both termostats are applied in every timestep.
The thermostat is applied to only the translational degrees of freedom
for the particles, which is an important consideration for finite-size
particles which have rotational degrees of freedom are being
thermostatted with these fixes. The translational degrees of freedom can
also have a bias velocity removed from them before thermostatting
thermostatted with these fixes. The translational degrees of freedom
can also have a bias velocity removed from them before thermostatting
takes place; see the description below.
The desired temperature at each timestep is a ramped value during the
@ -67,10 +67,10 @@ time. Thus it is easy to specify a time-dependent temperature.
IMPORTANT NOTE: Unlike the "fix nvt"_fix_nh.html command which
performs Nose/Hoover thermostatting AND time integration, these fixes
do NOT perform time integration. They only modify velocities to
effect thermostatting. Thus you must use a separate time integration
fix, like "fix nve"_fix_nve.html to actually update the positions of
atoms using the modified velocities. Likewise, these fixes should not
do NOT perform time integration. They only modify velocities to effect
thermostatting. Thus you must use a separate time integration fix,
like "fix nve"_fix_nve.html to actually update the positions of atoms
using the modified velocities. Likewise, these fixes should not
normally be used on atoms that also have their temperature controlled
by another fix - e.g. by "fix nvt"_fix_nh.html or "fix
langevin"_fix_langevin.html commands.