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            <ol class="chapter"><li><a href="../qcgpu.html"><strong aria-hidden="true">1.</strong> QCGPU</a></li><li><ol class="section"><li><a href="../getting-started.html"><strong aria-hidden="true">1.1.</strong> Getting Started</a></li></ol></li><li><a href="../user-guide/user-guide.html"><strong aria-hidden="true">2.</strong> User Guide</a></li><li><ol class="section"><li><a href="../user-guide/registers.html"><strong aria-hidden="true">2.1.</strong> Quantum Registers</a></li><li><a href="../user-guide/gates.html"><strong aria-hidden="true">2.2.</strong> Quantum Gates</a></li><li><a href="../user-guide/operations.html"><strong aria-hidden="true">2.3.</strong> Quantum Operations</a></li><li><a href="../user-guide/examples.html"><strong aria-hidden="true">2.4.</strong> Examples</a></li><li><a href="../user-guide/decoherence.html" class="active"><strong aria-hidden="true">2.5.</strong> Decoherence</a></li></ol></li><li><a href="../algorithms/algorithms.html"><strong aria-hidden="true">3.</strong> Algorithms</a></li><li><ol class="section"><li><a href="../algorithms/bernstein-vazirani.html"><strong aria-hidden="true">3.1.</strong> Bernstein-Vazirani</a></li><li><a href="../algorithms/deutsch-jozsa.html"><strong aria-hidden="true">3.2.</strong> Deutsch-Jozsa</a></li><li><a href="../algorithms/grover.html"><strong aria-hidden="true">3.3.</strong> Grovers</a></li><li><a href="../algorithms/shor.html"><strong aria-hidden="true">3.4.</strong> Shors</a></li><li><a href="../algorithms/super-dense.html"><strong aria-hidden="true">3.5.</strong> Super Dense Coding</a></li></ol></li></ol>
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                        <a class="header" href="#decoherence" id="decoherence"><h1>Decoherence</h1></a>
<p>QCGPU provides a way to easily simulate the effects of decoherence on the quantum computer. The effects are simulated by a random gate, corresponding to a random rotation around the \(z\) axis of the bloch sphere.</p>
<p>The angle of the rotation is a normal distrobuted value, with the varience as the strength factor <code>d</code>.</p>
<p>To avoid performance costs when not being used, decoherence can be enabled via a feature.</p>
<p>Change the dependency in <code>cargo.toml</code> to</p>
<pre><code class="language-toml">[dependencies]
qcgpu = { version = &quot;0.1&quot;, features = [&quot;decoherence&quot;] }
</code></pre>
<p>Now you can add decoherence to your simulator.</p>
<p>To set the amount of decoherence, the <code>set_decoherence</code> method is used. Its arguments are the strength of the decoherence.
This will affect all following gate applications.</p>
<pre><pre class="playpen"><code class="language-rust">
# #![allow(unused_variables)]
#fn main() {
use qcgpu::State;

let mut register = State::new(5, 0);
register.set_decoherence(0.4);
#}</code></pre></pre>
<p>You can also manually decohere the register based on the previously set strength value. This method is automatically called by all gate applications.</p>
<pre><pre class="playpen"><code class="language-rust">
# #![allow(unused_variables)]
#fn main() {
register.decohere();
#}</code></pre></pre>

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