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<p class='location'>Struct Gamma</p><div class="sidebar-elems"><div class="block items"><a class="sidebar-title" href="#methods">Methods</a><div class="sidebar-links"><a href="#method.new">new</a></div><a class="sidebar-title" href="#implementations">Trait Implementations</a><div class="sidebar-links"><a href="#impl-Debug">Debug</a><a href="#impl-Copy">Copy</a><a href="#impl-IndependentSample%3Cf64%3E">IndependentSample<f64></a><a href="#impl-Clone">Clone</a><a href="#impl-Sample%3Cf64%3E">Sample<f64></a></div></div><p class='location'><a href='../index.html'>rand</a>::<wbr><a href='index.html'>distributions</a></p><script>window.sidebarCurrent = {name: 'Gamma', ty: 'struct', relpath: ''};</script><script defer src="sidebar-items.js"></script></div>
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<h1 class='fqn'><span class='in-band'>Struct <a href='../index.html'>rand</a>::<wbr><a href='index.html'>distributions</a>::<wbr><a class="struct" href=''>Gamma</a></span><span class='out-of-band'><span id='render-detail'>
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[<span class='inner'>−</span>]
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</a>
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</span><a class='srclink' href='../../src/rand/distributions/gamma.rs.html#53-55' title='goto source code'>[src]</a></span></h1>
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<pre class='rust struct'>pub struct Gamma { /* fields omitted */ }</pre><div class='docblock'><p>The Gamma distribution <code>Gamma(shape, scale)</code> distribution.</p>
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<p>The density function of this distribution is</p>
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<pre><code class="language-text">f(x) = x^(k - 1) * exp(-x / θ) / (Γ(k) * θ^k)
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</code></pre>
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<p>where <code>Γ</code> is the Gamma function, <code>k</code> is the shape and <code>θ</code> is the
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scale and both <code>k</code> and <code>θ</code> are strictly positive.</p>
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<p>The algorithm used is that described by Marsaglia & Tsang 2000[1],
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falling back to directly sampling from an Exponential for <code>shape == 1</code>, and using the boosting technique described in [1] for
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<code>shape < 1</code>.</p>
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<h1 id="example" class="section-header"><a href="#example">Example</a></h1>
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<pre class="rust rust-example-rendered">
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<span class="kw">use</span> <span class="ident">rand</span>::<span class="ident">distributions</span>::{<span class="ident">IndependentSample</span>, <span class="ident">Gamma</span>};
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<span class="kw">let</span> <span class="ident">gamma</span> <span class="op">=</span> <span class="ident">Gamma</span>::<span class="ident">new</span>(<span class="number">2.0</span>, <span class="number">5.0</span>);
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<span class="kw">let</span> <span class="ident">v</span> <span class="op">=</span> <span class="ident">gamma</span>.<span class="ident">ind_sample</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">rand</span>::<span class="ident">thread_rng</span>());
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<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{} is from a Gamma(2, 5) distribution"</span>, <span class="ident">v</span>);</pre>
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<p>[1]: George Marsaglia and Wai Wan Tsang. 2000. "A Simple Method
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for Generating Gamma Variables" <em>ACM Trans. Math. Softw.</em> 26, 3
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(September 2000),
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363-372. DOI:<a href="http://doi.acm.org/10.1145/358407.358414">10.1145/358407.358414</a></p>
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</div>
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<h2 id='methods' class='small-section-header'>
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Methods<a href='#methods' class='anchor'></a>
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</h2>
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<h3 id='impl' class='impl'><span class='in-band'><code>impl <a class="struct" href="../../rand/distributions/gamma/struct.Gamma.html" title="struct rand::distributions::gamma::Gamma">Gamma</a></code><a href='#impl' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/rand/distributions/gamma.rs.html#95-114' title='goto source code'>[src]</a></span></h3>
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<div class='impl-items'><h4 id='method.new' class="method"><span id='new.v' class='invisible'><code>pub fn <a href='#method.new' class='fnname'>new</a>(shape: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.f64.html">f64</a>, scale: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.f64.html">f64</a>) -> <a class="struct" href="../../rand/distributions/gamma/struct.Gamma.html" title="struct rand::distributions::gamma::Gamma">Gamma</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/rand/distributions/gamma.rs.html#101-113' title='goto source code'>[src]</a></span></h4>
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<div class='docblock'><p>Construct an object representing the <code>Gamma(shape, scale)</code>
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distribution.</p>
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<p>Panics if <code>shape <= 0</code> or <code>scale <= 0</code>.</p>
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</div></div>
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<h2 id='implementations' class='small-section-header'>
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Trait Implementations<a href='#implementations' class='anchor'></a>
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</h2>
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<h3 id='impl-Debug' class='impl'><span class='in-band'><code>impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html" title="trait core::fmt::Debug">Debug</a> for <a class="struct" href="../../rand/distributions/gamma/struct.Gamma.html" title="struct rand::distributions::gamma::Gamma">Gamma</a></code><a href='#impl-Debug' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/rand/distributions/gamma.rs.html#52' title='goto source code'>[src]</a></span></h3>
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<div class='impl-items'><h4 id='method.fmt' class="method"><span id='fmt.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html#tymethod.fmt' class='fnname'>fmt</a>(&self, __arg_0: &mut <a class="struct" href="https://doc.rust-lang.org/nightly/core/fmt/struct.Formatter.html" title="struct core::fmt::Formatter">Formatter</a>) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.unit.html">()</a>, <a class="struct" href="https://doc.rust-lang.org/nightly/core/fmt/struct.Error.html" title="struct core::fmt::Error">Error</a>></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/rand/distributions/gamma.rs.html#52' title='goto source code'>[src]</a></span></h4>
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<div class='docblock'><p>Formats the value using the given formatter. <a href="https://doc.rust-lang.org/nightly/core/fmt/trait.Debug.html#tymethod.fmt">Read more</a></p>
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</div></div><h3 id='impl-Copy' class='impl'><span class='in-band'><code>impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/marker/trait.Copy.html" title="trait core::marker::Copy">Copy</a> for <a class="struct" href="../../rand/distributions/gamma/struct.Gamma.html" title="struct rand::distributions::gamma::Gamma">Gamma</a></code><a href='#impl-Copy' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/rand/distributions/gamma.rs.html#52' title='goto source code'>[src]</a></span></h3>
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<div class='impl-items'></div><h3 id='impl-IndependentSample%3Cf64%3E' class='impl'><span class='in-band'><code>impl <a class="trait" href="../../rand/distributions/trait.IndependentSample.html" title="trait rand::distributions::IndependentSample">IndependentSample</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.f64.html">f64</a>> for <a class="struct" href="../../rand/distributions/gamma/struct.Gamma.html" title="struct rand::distributions::gamma::Gamma">Gamma</a></code><a href='#impl-IndependentSample%3Cf64%3E' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/rand/distributions/gamma.rs.html#146-154' title='goto source code'>[src]</a></span></h3>
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<div class='impl-items'><h4 id='method.ind_sample' class="method"><span id='ind_sample.v' class='invisible'><code>fn <a href='../../rand/distributions/trait.IndependentSample.html#tymethod.ind_sample' class='fnname'>ind_sample</a><R>(&self, rng: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&mut </a>R) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.f64.html">f64</a> <span class="where fmt-newline">where<br> R: <a class="trait" href="../../rand/trait.Rng.html" title="trait rand::Rng">Rng</a>, </span></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/rand/distributions/gamma.rs.html#147-153' title='goto source code'>[src]</a></span></h4>
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<div class='docblock'><p>Generate a random value.</p>
|
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</div></div><h3 id='impl-Clone' class='impl'><span class='in-band'><code>impl <a class="trait" href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a> for <a class="struct" href="../../rand/distributions/gamma/struct.Gamma.html" title="struct rand::distributions::gamma::Gamma">Gamma</a></code><a href='#impl-Clone' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/rand/distributions/gamma.rs.html#52' title='goto source code'>[src]</a></span></h3>
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<div class='impl-items'><h4 id='method.clone' class="method"><span id='clone.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#tymethod.clone' class='fnname'>clone</a>(&self) -> <a class="struct" href="../../rand/distributions/gamma/struct.Gamma.html" title="struct rand::distributions::gamma::Gamma">Gamma</a></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/rand/distributions/gamma.rs.html#52' title='goto source code'>[src]</a></span></h4>
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<div class='docblock'><p>Returns a copy of the value. <a href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#tymethod.clone">Read more</a></p>
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</div><h4 id='method.clone_from' class="method"><span id='clone_from.v' class='invisible'><code>fn <a href='https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#method.clone_from' class='fnname'>clone_from</a>(&mut self, source: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&</a>Self)</code></span><span class='out-of-band'><div class='ghost'></div><div class='since' title='Stable since Rust version 1.0.0'>1.0.0</div><a class='srclink' href='https://doc.rust-lang.org/nightly/src/core/clone.rs.html#112-114' title='goto source code'>[src]</a></span></h4>
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<div class='docblock'><p>Performs copy-assignment from <code>source</code>. <a href="https://doc.rust-lang.org/nightly/core/clone/trait.Clone.html#method.clone_from">Read more</a></p>
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</div></div><h3 id='impl-Sample%3Cf64%3E' class='impl'><span class='in-band'><code>impl <a class="trait" href="../../rand/distributions/trait.Sample.html" title="trait rand::distributions::Sample">Sample</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.f64.html">f64</a>> for <a class="struct" href="../../rand/distributions/gamma/struct.Gamma.html" title="struct rand::distributions::gamma::Gamma">Gamma</a></code><a href='#impl-Sample%3Cf64%3E' class='anchor'></a></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/rand/distributions/gamma.rs.html#136-138' title='goto source code'>[src]</a></span></h3>
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<div class='impl-items'><h4 id='method.sample' class="method"><span id='sample.v' class='invisible'><code>fn <a href='../../rand/distributions/trait.Sample.html#tymethod.sample' class='fnname'>sample</a><R>(&mut self, rng: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.reference.html">&mut </a>R) -> <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.f64.html">f64</a> <span class="where fmt-newline">where<br> R: <a class="trait" href="../../rand/trait.Rng.html" title="trait rand::Rng">Rng</a>, </span></code></span><span class='out-of-band'><div class='ghost'></div><a class='srclink' href='../../src/rand/distributions/gamma.rs.html#137' title='goto source code'>[src]</a></span></h4>
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<div class='docblock'><p>Generate a random value of <code>Support</code>, using <code>rng</code> as the source of randomness. <a href="../../rand/distributions/trait.Sample.html#tymethod.sample">Read more</a></p>
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