| <!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="A distribution uniformly sampling numbers within a given range."><meta name="keywords" content="rust, rustlang, rust-lang, uniform"><title>rand_distr::uniform - Rust</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" type="text/css" href="../../normalize.css"><link rel="stylesheet" type="text/css" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" type="text/css" href="../../ayu.css" disabled><link rel="stylesheet" type="text/css" href="../../dark.css" disabled><link rel="stylesheet" type="text/css" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script src="../../crates.js"></script><script defer src="../../main.js"></script> |
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| </a><h2 class="location">Module uniform</h2><div class="sidebar-elems"><div class="block items"><ul><li><a href="#structs">Structs</a></li><li><a href="#traits">Traits</a></li></ul></div><div id="sidebar-vars" data-name="uniform" data-ty="mod" data-relpath="./"></div><script defer src="./sidebar-items.js"></script></div></nav><main><div class="width-limiter"><div class="sub-container"><a class="sub-logo-container" href="../../rand_distr/index.html"><img src="https://www.rust-lang.org/logos/rust-logo-128x128-blk.png" alt="logo"></a><nav class="sub"><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!" aria-haspopup="menu" title="themes"><img width="18" height="18" alt="Pick another theme!" src="../../brush.svg"></button><div id="theme-choices" role="menu"></div></div><form class="search-form"><div class="search-container"><div> |
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| <h1 class="fqn"><span class="in-band">Module <a href="../index.html">rand_distr</a>::<wbr><a class="mod" href="#">uniform</a><button id="copy-path" onclick="copy_path(this)" title="Copy item path to clipboard"><img src="../../clipboard.svg" width="19" height="18" alt="Copy item path"></button></span></h1><span class="out-of-band"> |
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| <details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>A distribution uniformly sampling numbers within a given range.</p> |
| <p><a href="../struct.Uniform.html" title="Uniform"><code>Uniform</code></a> is the standard distribution to sample uniformly from a range; |
| e.g. <code>Uniform::new_inclusive(1, 6)</code> can sample integers from 1 to 6, like a |
| standard die. <a href="../../rand/rng/trait.Rng.html#method.gen_range" title="Rng::gen_range"><code>Rng::gen_range</code></a> supports any type supported by |
| <a href="../struct.Uniform.html" title="Uniform"><code>Uniform</code></a>.</p> |
| <p>This distribution is provided with support for several primitive types |
| (all integer and floating-point types) as well as <a href="https://doc.rust-lang.org/nightly/core/time/struct.Duration.html" title="std::time::Duration"><code>std::time::Duration</code></a>, |
| and supports extension to user-defined types via a type-specific <em>back-end</em> |
| implementation.</p> |
| <p>The types <a href="struct.UniformInt.html"><code>UniformInt</code></a>, <a href="struct.UniformFloat.html"><code>UniformFloat</code></a> and <a href="struct.UniformDuration.html"><code>UniformDuration</code></a> are the |
| back-ends supporting sampling from primitive integer and floating-point |
| ranges as well as from <a href="https://doc.rust-lang.org/nightly/core/time/struct.Duration.html" title="std::time::Duration"><code>std::time::Duration</code></a>; these types do not normally |
| need to be used directly (unless implementing a derived back-end).</p> |
| <h2 id="example-usage" class="section-header"><a href="#example-usage">Example usage</a></h2> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use</span> <span class="ident">rand</span>::{<span class="ident">Rng</span>, <span class="ident">thread_rng</span>}; |
| <span class="kw">use</span> <span class="ident">rand::distributions::Uniform</span>; |
| |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident">thread_rng</span>(); |
| <span class="kw">let</span> <span class="ident">side</span> <span class="op">=</span> <span class="ident">Uniform::new</span>(<span class="op">-</span><span class="number">10.0</span>, <span class="number">10.0</span>); |
| |
| <span class="comment">// sample between 1 and 10 points</span> |
| <span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">rng</span>.<span class="ident">gen_range</span>(<span class="number">1</span>..<span class="op">=</span><span class="number">10</span>) { |
| <span class="comment">// sample a point from the square with sides -10 - 10 in two dimensions</span> |
| <span class="kw">let</span> (<span class="ident">x</span>, <span class="ident">y</span>) <span class="op">=</span> (<span class="ident">rng</span>.<span class="ident">sample</span>(<span class="ident">side</span>), <span class="ident">rng</span>.<span class="ident">sample</span>(<span class="ident">side</span>)); |
| <span class="macro">println!</span>(<span class="string">"Point: {}, {}"</span>, <span class="ident">x</span>, <span class="ident">y</span>); |
| }</code></pre></div> |
| <h2 id="extending-uniform-to-support-a-custom-type" class="section-header"><a href="#extending-uniform-to-support-a-custom-type">Extending <code>Uniform</code> to support a custom type</a></h2> |
| <p>To extend <a href="../struct.Uniform.html" title="Uniform"><code>Uniform</code></a> to support your own types, write a back-end which |
| implements the <a href="trait.UniformSampler.html"><code>UniformSampler</code></a> trait, then implement the <a href="trait.SampleUniform.html"><code>SampleUniform</code></a> |
| helper trait to “register” your back-end. See the <code>MyF32</code> example below.</p> |
| <p>At a minimum, the back-end needs to store any parameters needed for sampling |
| (e.g. the target range) and implement <code>new</code>, <code>new_inclusive</code> and <code>sample</code>. |
| Those methods should include an assert to check the range is valid (i.e. |
| <code>low < high</code>). The example below merely wraps another back-end.</p> |
| <p>The <code>new</code>, <code>new_inclusive</code> and <code>sample_single</code> functions use arguments of |
| type SampleBorrow<X> in order to support passing in values by reference or |
| by value. In the implementation of these functions, you can choose to |
| simply use the reference returned by <a href="trait.SampleBorrow.html#tymethod.borrow"><code>SampleBorrow::borrow</code></a>, or you can choose |
| to copy or clone the value, whatever is appropriate for your type.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use</span> <span class="ident">rand::prelude</span>::<span class="kw-2">*</span>; |
| <span class="kw">use</span> <span class="ident">rand::distributions::uniform</span>::{<span class="ident">Uniform</span>, <span class="ident">SampleUniform</span>, |
| <span class="ident">UniformSampler</span>, <span class="ident">UniformFloat</span>, <span class="ident">SampleBorrow</span>}; |
| |
| <span class="kw">struct</span> <span class="ident">MyF32</span>(<span class="ident">f32</span>); |
| |
| <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>, <span class="ident">Copy</span>, <span class="ident">Debug</span>)]</span> |
| <span class="kw">struct</span> <span class="ident">UniformMyF32</span>(<span class="ident">UniformFloat</span><span class="op"><</span><span class="ident">f32</span><span class="op">></span>); |
| |
| <span class="kw">impl</span> <span class="ident">UniformSampler</span> <span class="kw">for</span> <span class="ident">UniformMyF32</span> { |
| <span class="kw">type</span> <span class="ident">X</span> <span class="op">=</span> <span class="ident">MyF32</span>; |
| <span class="kw">fn</span> <span class="ident">new</span><span class="op"><</span><span class="ident">B1</span>, <span class="ident">B2</span><span class="op">></span>(<span class="ident">low</span>: <span class="ident">B1</span>, <span class="ident">high</span>: <span class="ident">B2</span>) -> <span class="self">Self</span> |
| <span class="kw">where</span> <span class="ident">B1</span>: <span class="ident">SampleBorrow</span><span class="op"><</span><span class="ident"><span class="self">Self</span>::X</span><span class="op">></span> <span class="op">+</span> <span class="ident">Sized</span>, |
| <span class="ident">B2</span>: <span class="ident">SampleBorrow</span><span class="op"><</span><span class="ident"><span class="self">Self</span>::X</span><span class="op">></span> <span class="op">+</span> <span class="ident">Sized</span> |
| { |
| <span class="ident">UniformMyF32</span>(<span class="ident">UniformFloat</span>::<span class="op"><</span><span class="ident">f32</span><span class="op">></span><span class="ident">::new</span>(<span class="ident">low</span>.<span class="ident">borrow</span>().<span class="number">0</span>, <span class="ident">high</span>.<span class="ident">borrow</span>().<span class="number">0</span>)) |
| } |
| <span class="kw">fn</span> <span class="ident">new_inclusive</span><span class="op"><</span><span class="ident">B1</span>, <span class="ident">B2</span><span class="op">></span>(<span class="ident">low</span>: <span class="ident">B1</span>, <span class="ident">high</span>: <span class="ident">B2</span>) -> <span class="self">Self</span> |
| <span class="kw">where</span> <span class="ident">B1</span>: <span class="ident">SampleBorrow</span><span class="op"><</span><span class="ident"><span class="self">Self</span>::X</span><span class="op">></span> <span class="op">+</span> <span class="ident">Sized</span>, |
| <span class="ident">B2</span>: <span class="ident">SampleBorrow</span><span class="op"><</span><span class="ident"><span class="self">Self</span>::X</span><span class="op">></span> <span class="op">+</span> <span class="ident">Sized</span> |
| { |
| <span class="ident">UniformMyF32</span>(<span class="ident">UniformFloat</span>::<span class="op"><</span><span class="ident">f32</span><span class="op">></span><span class="ident">::new_inclusive</span>( |
| <span class="ident">low</span>.<span class="ident">borrow</span>().<span class="number">0</span>, |
| <span class="ident">high</span>.<span class="ident">borrow</span>().<span class="number">0</span>, |
| )) |
| } |
| <span class="kw">fn</span> <span class="ident">sample</span><span class="op"><</span><span class="ident">R</span>: <span class="ident">Rng</span> <span class="op">+</span> <span class="question-mark">?</span><span class="ident">Sized</span><span class="op">></span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">rng</span>: <span class="kw-2">&mut</span> <span class="ident">R</span>) -> <span class="ident"><span class="self">Self</span>::X</span> { |
| <span class="ident">MyF32</span>(<span class="self">self</span>.<span class="number">0</span>.<span class="ident">sample</span>(<span class="ident">rng</span>)) |
| } |
| } |
| |
| <span class="kw">impl</span> <span class="ident">SampleUniform</span> <span class="kw">for</span> <span class="ident">MyF32</span> { |
| <span class="kw">type</span> <span class="ident">Sampler</span> <span class="op">=</span> <span class="ident">UniformMyF32</span>; |
| } |
| |
| <span class="kw">let</span> (<span class="ident">low</span>, <span class="ident">high</span>) <span class="op">=</span> (<span class="ident">MyF32</span>(<span class="number">17.0f32</span>), <span class="ident">MyF32</span>(<span class="number">22.0f32</span>)); |
| <span class="kw">let</span> <span class="ident">uniform</span> <span class="op">=</span> <span class="ident">Uniform::new</span>(<span class="ident">low</span>, <span class="ident">high</span>); |
| <span class="kw">let</span> <span class="ident">x</span> <span class="op">=</span> <span class="ident">uniform</span>.<span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">thread_rng</span>());</code></pre></div> |
| </div></details><h2 id="structs" class="small-section-header"><a href="#structs">Structs</a></h2> |
| <div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.Uniform.html" title="rand_distr::uniform::Uniform struct">Uniform</a></div><div class="item-right docblock-short"><p>Sample values uniformly between two bounds.</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.UniformChar.html" title="rand_distr::uniform::UniformChar struct">UniformChar</a></div><div class="item-right docblock-short"><p>The back-end implementing <a href="trait.UniformSampler.html" title="UniformSampler"><code>UniformSampler</code></a> for <code>char</code>.</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.UniformDuration.html" title="rand_distr::uniform::UniformDuration struct">UniformDuration</a></div><div class="item-right docblock-short"><p>The back-end implementing <a href="trait.UniformSampler.html" title="UniformSampler"><code>UniformSampler</code></a> for <code>Duration</code>.</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.UniformFloat.html" title="rand_distr::uniform::UniformFloat struct">UniformFloat</a></div><div class="item-right docblock-short"><p>The back-end implementing <a href="trait.UniformSampler.html" title="UniformSampler"><code>UniformSampler</code></a> for floating-point types.</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="struct" href="struct.UniformInt.html" title="rand_distr::uniform::UniformInt struct">UniformInt</a></div><div class="item-right docblock-short"><p>The back-end implementing <a href="trait.UniformSampler.html" title="UniformSampler"><code>UniformSampler</code></a> for integer types.</p> |
| </div></div></div><h2 id="traits" class="small-section-header"><a href="#traits">Traits</a></h2> |
| <div class="item-table"><div class="item-row"><div class="item-left module-item"><a class="trait" href="trait.SampleBorrow.html" title="rand_distr::uniform::SampleBorrow trait">SampleBorrow</a></div><div class="item-right docblock-short"><p>Helper trait similar to <a href="https://doc.rust-lang.org/nightly/core/borrow/trait.Borrow.html"><code>Borrow</code></a> but implemented |
| only for SampleUniform and references to SampleUniform in |
| order to resolve ambiguity issues.</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="trait" href="trait.SampleRange.html" title="rand_distr::uniform::SampleRange trait">SampleRange</a></div><div class="item-right docblock-short"><p>Range that supports generating a single sample efficiently.</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="trait" href="trait.SampleUniform.html" title="rand_distr::uniform::SampleUniform trait">SampleUniform</a></div><div class="item-right docblock-short"><p>Helper trait for creating objects using the correct implementation of |
| <a href="trait.UniformSampler.html" title="UniformSampler"><code>UniformSampler</code></a> for the sampling type.</p> |
| </div></div><div class="item-row"><div class="item-left module-item"><a class="trait" href="trait.UniformSampler.html" title="rand_distr::uniform::UniformSampler trait">UniformSampler</a></div><div class="item-right docblock-short"><p>Helper trait handling actual uniform sampling.</p> |
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