lammps/doc/timestep.html

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<div class="section" id="timestep-command">
<span id="index-0"></span><h1>timestep command<a class="headerlink" href="#timestep-command" title="Permalink to this headline"></a></h1>
<div class="section" id="syntax">
<h2>Syntax<a class="headerlink" href="#syntax" title="Permalink to this headline"></a></h2>
<div class="highlight-python"><div class="highlight"><pre>timestep dt
</pre></div>
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<ul class="simple">
<li>dt = timestep size (time units)</li>
</ul>
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<div class="section" id="examples">
<h2>Examples<a class="headerlink" href="#examples" title="Permalink to this headline"></a></h2>
<div class="highlight-python"><div class="highlight"><pre>timestep 2.0
timestep 0.003
</pre></div>
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<div class="section" id="description">
<h2>Description<a class="headerlink" href="#description" title="Permalink to this headline"></a></h2>
<p>Set the timestep size for subsequent molecular dynamics simulations.
See the <a class="reference internal" href="units.html"><em>units</em></a> command for the time units associated with
each choice of units that LAMMPS supports.</p>
<p>The default value for the timestep size also depends on the choice of
units for the simulation; see the default values below.</p>
<p>When the <a class="reference internal" href="run_style.html"><em>run style</em></a> is <em>respa</em>, dt is the timestep for
the outer loop (largest) timestep.</p>
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<div class="section" id="restrictions">
<h2>Restrictions<a class="headerlink" href="#restrictions" title="Permalink to this headline"></a></h2>
<blockquote>
<div>none</div></blockquote>
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<div class="section" id="related-commands">
<h2>Related commands<a class="headerlink" href="#related-commands" title="Permalink to this headline"></a></h2>
<p><a class="reference internal" href="fix_dt_reset.html"><em>fix dt/reset</em></a>, <a class="reference internal" href="run.html"><em>run</em></a>,
<a class="reference internal" href="run_style.html"><em>run_style</em></a> respa, <a class="reference internal" href="units.html"><em>units</em></a></p>
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<div class="section" id="default">
<h2>Default<a class="headerlink" href="#default" title="Permalink to this headline"></a></h2>
<table border="1" class="docutils">
<colgroup>
<col width="48%" />
<col width="18%" />
<col width="34%" />
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<tbody valign="top">
<tr class="row-odd"><td>choice of <a class="reference internal" href="units.html"><em>units</em></a></td>
<td>time units</td>
<td>default timestep size</td>
</tr>
<tr class="row-even"><td>lj</td>
<td>tau</td>
<td>0.005 tau</td>
</tr>
<tr class="row-odd"><td>real</td>
<td>fmsec</td>
<td>1.0 fmsec</td>
</tr>
<tr class="row-even"><td>metal</td>
<td>psec</td>
<td>0.001 psec</td>
</tr>
<tr class="row-odd"><td>si</td>
<td>sec</td>
<td>1.0e-8 sec (10 nsec)</td>
</tr>
<tr class="row-even"><td>cgs</td>
<td>sec</td>
<td>1.0e-8 sec (10 nsec)</td>
</tr>
<tr class="row-odd"><td>electron</td>
<td>fmsec</td>
<td>0.001 fmsec</td>
</tr>
<tr class="row-even"><td>micro</td>
<td>usec</td>
<td>2.0 usec</td>
</tr>
<tr class="row-odd"><td>nano</td>
<td>nsec</td>
<td>0.00045 nsec</td>
</tr>
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