described in <A HREF = "#Dunweg">(Dunweg)</A>, where a uniform random number is used

(instead of a Gaussian random number) for speed.

</P>

<P>Note that the thermostat effect of this fix is applied to only the

translational degrees of freedom for the particles, which is an

important consideration if extended spherical or aspherical particles

which have rotational degrees of freedom are being thermostatted with

this fix.  The translational degrees of freedom can also have a bias

velocity removed from them before thermostatting takes place; see the

description below.

</P>

<P>IMPORTANT NOTE: Unlike the <A HREF = "fix_nvt.html">fix nvt</A> command which

performs Nose/Hoover thermostatting AND time integration, this fix

does NOT perform time integration.  It only modifies forces to effect

Thus the dynamics of the system will not be identical on two runs on

different numbers of processors.

</P>

<P>The keyword <I>axes</I> can be used to specify which dimensions to add Ff

and Fr to.  A flag of 0 means skip that dimension; a flag of 1 means

include that dimension.  The default is 1 for all 3 dimensions.

</P>

<P>The keyword <I>scale</I> allows the damp factor to be scaled up or down by

the specified factor for atoms of that type.  This can be useful when

different atom types have different sizes or masses.  It can be used

<P><B>Related commands:</B>

</P>

<P><A HREF = "fix_nvt.html">fix nvt</A>, <A HREF = "fix_temp_rescale.html">fix temp/rescale</A>, <A HREF = "fix_viscous.html">fix

viscous</A>

viscous</A>, <A HREF = "fix_nvt.html">fix nvt</A>

</P>

<P><B>Default:</B>

</P>

Tstart,Tstop = desired temperature at start/end of run (temperature units) :l

damp = damping parameter (time units) :l

seed = random # seed to use for white noise (positive integer) :l

zero or more keyword/value pairs may be appended :l

keyword = {scale}

  {scale} values = type ratio

described in "(Dunweg)"_#Dunweg, where a uniform random number is used

(instead of a Gaussian random number) for speed.

Note that the thermostat effect of this fix is applied to only the

translational degrees of freedom for the particles, which is an

important consideration if extended spherical or aspherical particles

which have rotational degrees of freedom are being thermostatted with

this fix.  The translational degrees of freedom can also have a bias

velocity removed from them before thermostatting takes place; see the

description below.

IMPORTANT NOTE: Unlike the "fix nvt"_fix_nvt.html command which

performs Nose/Hoover thermostatting AND time integration, this fix

does NOT perform time integration.  It only modifies forces to effect

Thus the dynamics of the system will not be identical on two runs on

different numbers of processors.

The keyword {axes} can be used to specify which dimensions to add Ff

and Fr to.  A flag of 0 means skip that dimension; a flag of 1 means

include that dimension.  The default is 1 for all 3 dimensions.

The keyword {scale} allows the damp factor to be scaled up or down by

the specified factor for atoms of that type.  This can be useful when

different atom types have different sizes or masses.  It can be used

[Related commands:]

"fix nvt"_fix_nvt.html, "fix temp/rescale"_fix_temp_rescale.html, "fix

viscous"_fix_viscous.html

viscous"_fix_viscous.html, "fix nvt"_fix_nvt.html

[Default:]

creates a system trajectory consistent with the isothermal-isobaric

ensemble.

</P>

<P>The thermostat is applied to only the translational degrees of freedom

for the particles.  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

run from <I>Tstart</I> to <I>Tstop</I>.  The <I>Tdamp</I> parameter is specified in

time units and determines how rapidly the temperature is relaxed.  For

creates a system trajectory consistent with the isothermal-isobaric

ensemble.

The thermostat is applied to only the translational degrees of freedom

for the particles.  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

run from {Tstart} to {Tstop}.  The {Tdamp} parameter is specified in

time units and determines how rapidly the temperature is relaxed.  For

</PRE>

<P><B>Description:</B>

</P>

<P>Perform constant NPT integration to update positions, velocities, 

and angular velocity each timestep for aspherical or ellipsoidal 

particles in the group using a Nose/Hoover temperature

<P>Perform constant NPT integration to update position, velocity,

orientation, and angular velocity each timestep for aspherical or

ellipsoidal particles in the group using a Nose/Hoover temperature

thermostat and Nose/Hoover pressure barostat.  P is pressure; T is

temperature.  This creates a system trajectory consistent with the

isothermal-isobaric ensemble.

</P>

<P>The thermostat is applied to both the translational and rotational

degrees of freedom for the aspherical particles, assuming a compute is

used which calculates a temperature that includes the rotational

degrees of freedom (see below).  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

run from <I>Tstart</I> to <I>Tstop</I>.  The <I>Tdamp</I> parameter is specified in

time units and determines how rapidly the temperature is relaxed.  For

It also means that changing attributes of <I>thermo_temp</I> or

<I>thermo_press</I> will have no effect on this fix.

</P>

<P>Like other fixes that perform thermostatting, this fix can be used

with <A HREF = "compute.html">compute commands</A> that calculate a temperature

after removing a "bias" from the atom velocities.  E.g. removing the

center-of-mass velocity from a group of atoms or only calculating

temperature on the x-component of velocity or only calculating

temperature for atoms in a geometric region.  This is not done by

default, but only if the <A HREF = "fix_modify.html">fix_modify</A> command is used

to assign a temperature compute to this fix that includes such a bias

term.  See the doc pages for individual <A HREF = "compute.html">compute

commands</A> to determine which ones include a bias.  In

this case, the thermostat works in the following manner: the current

temperature is calculated taking the bias into account, bias is

removed from each atom, thermostatting is performed on the remaining

thermal degrees of freedom, and the bias is added back in.

</P>

<P><B>Restart, fix_modify, output, run start/stop, minimize info:</B>

</P>

<P>This fix writes the state of the Nose/Hoover thermostat and barostat

LAMMPS was built with that package.  See the <A HREF = "Section_start.html#2_3">Making

LAMMPS</A> section for more info.

</P>

<P>This fix requires that particles be represented as extended ellipsoids

and not point particles.  This means they will have an angular

momentum and a shape which is determined by the <A HREF = "shape.html">shape</A>

command.

</P>

<P>Any dimension being adjusted by this fix must be periodic.  A

dimension whose target pressures are specified as NULL can be

non-periodic or periodic.

</P>

<P><B>Related commands:</B>

</P>

<P><A HREF = "fix_npt.html">fix npt</A>, <A HREF = "fix_nve_asphere.html">fix nve_asphere</A>,

<A HREF = "fix_modify.html">fix_modify</A>

<P><A HREF = "fix_npt.html">fix npt</A>, <A HREF = "fix_nve_asphere.html">fix nve_asphere</A>, <A HREF = "fix_npt_asphere.html">fix

npt_asphere</A>, <A HREF = "fix_modify.html">fix_modify</A>

</P>

<P><B>Default:</B>

</P>