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<div class="section" id="timestep-command">
<span id="index-0"></span><h1>timestep command</h1>
<div class="section" id="syntax">
<h2>Syntax</h2>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">timestep</span> <span class="n">dt</span>
</pre></div>
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<ul class="simple">
<li>dt = timestep size (time units)</li>
</ul>
</div>
<div class="section" id="examples">
<h2>Examples</h2>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">timestep</span> <span class="mf">2.0</span>
<span class="n">timestep</span> <span class="mf">0.003</span>
</pre></div>
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<div class="section" id="description">
<h2>Description</h2>
<p>Set the timestep size for subsequent molecular dynamics simulations.
See the <a class="reference internal" href="units.html"><span class="doc">units</span></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"><span class="doc">run style</span></a> is <em>respa</em>, dt is the timestep for
the outer loop (largest) timestep.</p>
</div>
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<h2>Restrictions</h2>
<blockquote>
<div>none</div></blockquote>
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<div class="section" id="related-commands">
<h2>Related commands</h2>
<p><a class="reference internal" href="fix_dt_reset.html"><span class="doc">fix dt/reset</span></a>, <a class="reference internal" href="run.html"><span class="doc">run</span></a>,
<a class="reference internal" href="run_style.html"><span class="doc">run_style</span></a> respa, <a class="reference internal" href="units.html"><span class="doc">units</span></a></p>
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<div class="section" id="default">
<h2>Default</h2>
<table border="1" class="docutils">
<colgroup>
<col width="48%" />
<col width="18%" />
<col width="34%" />
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<tr class="row-odd"><td>choice of <a class="reference internal" href="units.html"><span class="doc">units</span></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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