<h1>compute temp/cuda command<aclass="headerlink"href="#compute-temp-cuda-command"title="Permalink to this headline">¶</a></h1>
<divclass="section"id="syntax">
<h2>Syntax<aclass="headerlink"href="#syntax"title="Permalink to this headline">¶</a></h2>
<divclass="highlight-python"><divclass="highlight"><pre>compute ID group-ID temp
</pre></div>
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<ulclass="simple">
<li>ID, group-ID are documented in <aclass="reference internal"href="compute.html"><em>compute</em></a> command</li>
<li>temp = style name of this compute command</li>
</ul>
</div>
<divclass="section"id="examples">
<h2>Examples<aclass="headerlink"href="#examples"title="Permalink to this headline">¶</a></h2>
<divclass="highlight-python"><divclass="highlight"><pre>compute 1 all temp
compute myTemp mobile temp
</pre></div>
</div>
</div>
<divclass="section"id="description">
<h2>Description<aclass="headerlink"href="#description"title="Permalink to this headline">¶</a></h2>
<p>Define a computation that calculates the temperature of a group of
atoms. A compute of this style can be used by any command that
computes a temperature, e.g. <aclass="reference internal"href="thermo_modify.html"><em>thermo_modify</em></a>, <aclass="reference internal"href="fix_temp_rescale.html"><em>fix temp/rescale</em></a>, <aclass="reference internal"href="fix_nh.html"><em>fix npt</em></a>, etc.</p>
<p>The temperature is calculated by the formula KE = dim/2 N k T, where
KE = total kinetic energy of the group of atoms (sum of 1/2 m v^2),
dim = 2 or 3 = dimensionality of the simulation, N = number of atoms
in the group, k = Boltzmann constant, and T = temperature.</p>
<p>A kinetic energy tensor, stored as a 6-element vector, is also
calculated by this compute for use in the computation of a pressure
tensor. The formula for the components of the tensor is the same as
the above formula, except that v^2 is replaced by vx*vy for the xy
component, etc. The 6 components of the vector are ordered xx, yy,
zz, xy, xz, yz.</p>
<p>The number of atoms contributing to the temperature is assumed to be
constant for the duration of the run; use the <em>dynamic</em> option of the
<aclass="reference internal"href="compute_modify.html"><em>compute_modify</em></a> command if this is not the case.</p>
<p>This compute subtracts out degrees-of-freedom due to fixes that
constrain molecular motion, such as <aclass="reference internal"href="fix_shake.html"><em>fix shake</em></a> and
<aclass="reference internal"href="fix_rigid.html"><em>fix rigid</em></a>. This means the temperature of groups of
atoms that include these constraints will be computed correctly. If
needed, the subtracted degrees-of-freedom can be altered using the
<em>extra</em> option of the <aclass="reference internal"href="compute_modify.html"><em>compute_modify</em></a> command.</p>
<p>A compute of this style with the ID of “thermo_temp” is created when
LAMMPS starts up, as if this command were in the input script:</p>
<divclass="highlight-python"><divclass="highlight"><pre>compute thermo_temp all temp
</pre></div>
</div>
<p>See the “thermo_style” command for more details.</p>
<p>See <aclass="reference internal"href="Section_howto.html#howto-16"><span>this howto section</span></a> of the manual for
a discussion of different ways to compute temperature and perform
thermostatting.</p>
<hrclass="docutils"/>
<p>Styles with a <em>cuda</em> suffix are functionally the same as the
corresponding style without the suffix. They have been optimized to
run faster, depending on your available hardware, as discussed in
<aclass="reference internal"href="Section_accelerate.html"><em>Section_accelerate</em></a> of the manual. The
accelerated styles take the same arguments and should produce the same
results, except for round-off and precision issues.</p>
<p>These accelerated styles are part of the USER-CUDA package. They are
only enabled if LAMMPS was built with that package. See the <aclass="reference internal"href="Section_start.html#start-3"><span>Making LAMMPS</span></a> section for more info.</p>
<p>You can specify the accelerated styles explicitly in your input script
by including their suffix, or you can use the <aclass="reference internal"href="Section_start.html#start-7"><span>-suffix command-line switch</span></a> when you invoke LAMMPS, or you can
use the <aclass="reference internal"href="suffix.html"><em>suffix</em></a> command in your input script.</p>
<p>See <aclass="reference internal"href="Section_accelerate.html"><em>Section_accelerate</em></a> of the manual for
more instructions on how to use the accelerated styles effectively.</p>
<hrclass="docutils"/>
<p><strong>Output info:</strong></p>
<p>This compute calculates a global scalar (the temperature) and a global
vector of length 6 (KE tensor), which can be accessed by indices 1-6.
These values can be used by any command that uses global scalar or
vector values from a compute as input. See <aclass="reference internal"href="Section_howto.html#howto-15"><span>this section</span></a> for an overview of LAMMPS output
options.</p>
<p>The scalar value calculated by this compute is “intensive”. The
vector are “extensive”.</p>
<p>The scalar value will be in temperature <aclass="reference internal"href="units.html"><em>units</em></a>. The
vector values will be in energy <aclass="reference internal"href="units.html"><em>units</em></a>.</p>
</div>
<divclass="section"id="restrictions">
<h2>Restrictions<aclass="headerlink"href="#restrictions"title="Permalink to this headline">¶</a></h2>
<blockquote>
<div>none</div></blockquote>
</div>
<divclass="section"id="related-commands">
<h2>Related commands<aclass="headerlink"href="#related-commands"title="Permalink to this headline">¶</a></h2>
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