| <!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="Source of the Rust file `src/distributions/bernoulli.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>bernoulli.rs - source</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><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script> |
| <noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="shortcut icon" href="https://www.rust-lang.org/favicon.ico"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><div class="sidebar-menu" role="button">☰</div><a class="sidebar-logo" href="../../../rand/index.html"><div class="logo-container"><img src="https://www.rust-lang.org/logos/rust-logo-128x128-blk.png" alt="logo"></div> |
| </a></nav><main><div class="width-limiter"><div class="sub-container"><a class="sub-logo-container" href="../../../rand/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> |
| <input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><button type="button" id="help-button" title="help">?</button><a id="settings-menu" href="../../../settings.html" title="settings"><img width="18" height="18" alt="Change settings" src="../../../wheel.svg"></a></div></form></nav></div><section id="main-content" class="content"><div class="example-wrap"><pre class="line-numbers"><span id="1"> 1</span> |
| <span id="2"> 2</span> |
| <span id="3"> 3</span> |
| <span id="4"> 4</span> |
| <span id="5"> 5</span> |
| <span id="6"> 6</span> |
| <span id="7"> 7</span> |
| <span id="8"> 8</span> |
| <span id="9"> 9</span> |
| <span id="10"> 10</span> |
| <span id="11"> 11</span> |
| <span id="12"> 12</span> |
| <span id="13"> 13</span> |
| <span id="14"> 14</span> |
| <span id="15"> 15</span> |
| <span id="16"> 16</span> |
| <span id="17"> 17</span> |
| <span id="18"> 18</span> |
| <span id="19"> 19</span> |
| <span id="20"> 20</span> |
| <span id="21"> 21</span> |
| <span id="22"> 22</span> |
| <span id="23"> 23</span> |
| <span id="24"> 24</span> |
| <span id="25"> 25</span> |
| <span id="26"> 26</span> |
| <span id="27"> 27</span> |
| <span id="28"> 28</span> |
| <span id="29"> 29</span> |
| <span id="30"> 30</span> |
| <span id="31"> 31</span> |
| <span id="32"> 32</span> |
| <span id="33"> 33</span> |
| <span id="34"> 34</span> |
| <span id="35"> 35</span> |
| <span id="36"> 36</span> |
| <span id="37"> 37</span> |
| <span id="38"> 38</span> |
| <span id="39"> 39</span> |
| <span id="40"> 40</span> |
| <span id="41"> 41</span> |
| <span id="42"> 42</span> |
| <span id="43"> 43</span> |
| <span id="44"> 44</span> |
| <span id="45"> 45</span> |
| <span id="46"> 46</span> |
| <span id="47"> 47</span> |
| <span id="48"> 48</span> |
| <span id="49"> 49</span> |
| <span id="50"> 50</span> |
| <span id="51"> 51</span> |
| <span id="52"> 52</span> |
| <span id="53"> 53</span> |
| <span id="54"> 54</span> |
| <span id="55"> 55</span> |
| <span id="56"> 56</span> |
| <span id="57"> 57</span> |
| <span id="58"> 58</span> |
| <span id="59"> 59</span> |
| <span id="60"> 60</span> |
| <span id="61"> 61</span> |
| <span id="62"> 62</span> |
| <span id="63"> 63</span> |
| <span id="64"> 64</span> |
| <span id="65"> 65</span> |
| <span id="66"> 66</span> |
| <span id="67"> 67</span> |
| <span id="68"> 68</span> |
| <span id="69"> 69</span> |
| <span id="70"> 70</span> |
| <span id="71"> 71</span> |
| <span id="72"> 72</span> |
| <span id="73"> 73</span> |
| <span id="74"> 74</span> |
| <span id="75"> 75</span> |
| <span id="76"> 76</span> |
| <span id="77"> 77</span> |
| <span id="78"> 78</span> |
| <span id="79"> 79</span> |
| <span id="80"> 80</span> |
| <span id="81"> 81</span> |
| <span id="82"> 82</span> |
| <span id="83"> 83</span> |
| <span id="84"> 84</span> |
| <span id="85"> 85</span> |
| <span id="86"> 86</span> |
| <span id="87"> 87</span> |
| <span id="88"> 88</span> |
| <span id="89"> 89</span> |
| <span id="90"> 90</span> |
| <span id="91"> 91</span> |
| <span id="92"> 92</span> |
| <span id="93"> 93</span> |
| <span id="94"> 94</span> |
| <span id="95"> 95</span> |
| <span id="96"> 96</span> |
| <span id="97"> 97</span> |
| <span id="98"> 98</span> |
| <span id="99"> 99</span> |
| <span id="100">100</span> |
| <span id="101">101</span> |
| <span id="102">102</span> |
| <span id="103">103</span> |
| <span id="104">104</span> |
| <span id="105">105</span> |
| <span id="106">106</span> |
| <span id="107">107</span> |
| <span id="108">108</span> |
| <span id="109">109</span> |
| <span id="110">110</span> |
| <span id="111">111</span> |
| <span id="112">112</span> |
| <span id="113">113</span> |
| <span id="114">114</span> |
| <span id="115">115</span> |
| <span id="116">116</span> |
| <span id="117">117</span> |
| <span id="118">118</span> |
| <span id="119">119</span> |
| <span id="120">120</span> |
| <span id="121">121</span> |
| <span id="122">122</span> |
| <span id="123">123</span> |
| <span id="124">124</span> |
| <span id="125">125</span> |
| <span id="126">126</span> |
| <span id="127">127</span> |
| <span id="128">128</span> |
| <span id="129">129</span> |
| <span id="130">130</span> |
| <span id="131">131</span> |
| <span id="132">132</span> |
| <span id="133">133</span> |
| <span id="134">134</span> |
| <span id="135">135</span> |
| <span id="136">136</span> |
| <span id="137">137</span> |
| <span id="138">138</span> |
| <span id="139">139</span> |
| <span id="140">140</span> |
| <span id="141">141</span> |
| <span id="142">142</span> |
| <span id="143">143</span> |
| <span id="144">144</span> |
| <span id="145">145</span> |
| <span id="146">146</span> |
| <span id="147">147</span> |
| <span id="148">148</span> |
| <span id="149">149</span> |
| <span id="150">150</span> |
| <span id="151">151</span> |
| <span id="152">152</span> |
| <span id="153">153</span> |
| <span id="154">154</span> |
| <span id="155">155</span> |
| <span id="156">156</span> |
| <span id="157">157</span> |
| <span id="158">158</span> |
| <span id="159">159</span> |
| <span id="160">160</span> |
| <span id="161">161</span> |
| <span id="162">162</span> |
| <span id="163">163</span> |
| <span id="164">164</span> |
| <span id="165">165</span> |
| <span id="166">166</span> |
| <span id="167">167</span> |
| <span id="168">168</span> |
| <span id="169">169</span> |
| <span id="170">170</span> |
| <span id="171">171</span> |
| <span id="172">172</span> |
| <span id="173">173</span> |
| <span id="174">174</span> |
| <span id="175">175</span> |
| <span id="176">176</span> |
| <span id="177">177</span> |
| <span id="178">178</span> |
| <span id="179">179</span> |
| <span id="180">180</span> |
| <span id="181">181</span> |
| <span id="182">182</span> |
| <span id="183">183</span> |
| <span id="184">184</span> |
| <span id="185">185</span> |
| <span id="186">186</span> |
| <span id="187">187</span> |
| <span id="188">188</span> |
| <span id="189">189</span> |
| <span id="190">190</span> |
| <span id="191">191</span> |
| <span id="192">192</span> |
| <span id="193">193</span> |
| <span id="194">194</span> |
| <span id="195">195</span> |
| <span id="196">196</span> |
| <span id="197">197</span> |
| <span id="198">198</span> |
| <span id="199">199</span> |
| <span id="200">200</span> |
| <span id="201">201</span> |
| <span id="202">202</span> |
| <span id="203">203</span> |
| <span id="204">204</span> |
| <span id="205">205</span> |
| <span id="206">206</span> |
| <span id="207">207</span> |
| <span id="208">208</span> |
| <span id="209">209</span> |
| <span id="210">210</span> |
| <span id="211">211</span> |
| <span id="212">212</span> |
| <span id="213">213</span> |
| <span id="214">214</span> |
| </pre><pre class="rust"><code><span class="comment">// Copyright 2018 Developers of the Rand project.</span> |
| <span class="comment">//</span> |
| <span class="comment">// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or</span> |
| <span class="comment">// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license</span> |
| <span class="comment">// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your</span> |
| <span class="comment">// option. This file may not be copied, modified, or distributed</span> |
| <span class="comment">// except according to those terms.</span> |
| |
| <span class="doccomment">//! The Bernoulli distribution.</span> |
| |
| <span class="kw">use</span> <span class="ident"><span class="kw">crate</span>::distributions::Distribution</span>; |
| <span class="kw">use</span> <span class="ident"><span class="kw">crate</span>::Rng</span>; |
| <span class="kw">use</span> <span class="ident">core</span>::{<span class="ident">fmt</span>, <span class="ident">u64</span>}; |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"serde1"</span>)]</span> |
| <span class="kw">use</span> <span class="ident">serde</span>::{<span class="ident">Serialize</span>, <span class="ident">Deserialize</span>}; |
| <span class="doccomment">/// The Bernoulli distribution.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This is a special case of the Binomial distribution where `n = 1`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Example</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// ```rust</span> |
| <span class="doccomment">/// use rand::distributions::{Bernoulli, Distribution};</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// let d = Bernoulli::new(0.3).unwrap();</span> |
| <span class="doccomment">/// let v = d.sample(&mut rand::thread_rng());</span> |
| <span class="doccomment">/// println!("{} is from a Bernoulli distribution", v);</span> |
| <span class="doccomment">/// ```</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Precision</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This `Bernoulli` distribution uses 64 bits from the RNG (a `u64`),</span> |
| <span class="doccomment">/// so only probabilities that are multiples of 2<sup>-64</sup> can be</span> |
| <span class="doccomment">/// represented.</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="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"serde1"</span>, <span class="ident">derive</span>(<span class="ident">Serialize</span>, <span class="ident">Deserialize</span>))]</span> |
| <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Bernoulli</span> { |
| <span class="doccomment">/// Probability of success, relative to the maximal integer.</span> |
| <span class="ident">p_int</span>: <span class="ident">u64</span>, |
| } |
| |
| <span class="comment">// To sample from the Bernoulli distribution we use a method that compares a</span> |
| <span class="comment">// random `u64` value `v < (p * 2^64)`.</span> |
| <span class="comment">//</span> |
| <span class="comment">// If `p == 1.0`, the integer `v` to compare against can not represented as a</span> |
| <span class="comment">// `u64`. We manually set it to `u64::MAX` instead (2^64 - 1 instead of 2^64).</span> |
| <span class="comment">// Note that value of `p < 1.0` can never result in `u64::MAX`, because an</span> |
| <span class="comment">// `f64` only has 53 bits of precision, and the next largest value of `p` will</span> |
| <span class="comment">// result in `2^64 - 2048`.</span> |
| <span class="comment">//</span> |
| <span class="comment">// Also there is a 100% theoretical concern: if someone consistently wants to</span> |
| <span class="comment">// generate `true` using the Bernoulli distribution (i.e. by using a probability</span> |
| <span class="comment">// of `1.0`), just using `u64::MAX` is not enough. On average it would return</span> |
| <span class="comment">// false once every 2^64 iterations. Some people apparently care about this</span> |
| <span class="comment">// case.</span> |
| <span class="comment">//</span> |
| <span class="comment">// That is why we special-case `u64::MAX` to always return `true`, without using</span> |
| <span class="comment">// the RNG, and pay the performance price for all uses that *are* reasonable.</span> |
| <span class="comment">// Luckily, if `new()` and `sample` are close, the compiler can optimize out the</span> |
| <span class="comment">// extra check.</span> |
| <span class="kw">const</span> <span class="ident">ALWAYS_TRUE</span>: <span class="ident">u64</span> <span class="op">=</span> <span class="ident">u64::MAX</span>; |
| |
| <span class="comment">// This is just `2.0.powi(64)`, but written this way because it is not available</span> |
| <span class="comment">// in `no_std` mode.</span> |
| <span class="kw">const</span> <span class="ident">SCALE</span>: <span class="ident">f64</span> <span class="op">=</span> <span class="number">2.0</span> <span class="op">*</span> (<span class="number">1u64</span> <span class="op"><</span><span class="op"><</span> <span class="number">63</span>) <span class="kw">as</span> <span class="ident">f64</span>; |
| |
| <span class="doccomment">/// Error type returned from `Bernoulli::new`.</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 class="ident">PartialEq</span>, <span class="ident">Eq</span>)]</span> |
| <span class="kw">pub</span> <span class="kw">enum</span> <span class="ident">BernoulliError</span> { |
| <span class="doccomment">/// `p < 0` or `p > 1`.</span> |
| <span class="ident">InvalidProbability</span>, |
| } |
| |
| <span class="kw">impl</span> <span class="ident">fmt::Display</span> <span class="kw">for</span> <span class="ident">BernoulliError</span> { |
| <span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&mut</span> <span class="ident">fmt::Formatter</span><span class="op"><</span><span class="lifetime">'_</span><span class="op">></span>) -> <span class="ident">fmt::Result</span> { |
| <span class="ident">f</span>.<span class="ident">write_str</span>(<span class="kw">match</span> <span class="self">self</span> { |
| <span class="ident">BernoulliError::InvalidProbability</span> => <span class="string">"p is outside [0, 1] in Bernoulli distribution"</span>, |
| }) |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"std"</span>)]</span> |
| <span class="kw">impl</span> <span class="ident">::std::error::Error</span> <span class="kw">for</span> <span class="ident">BernoulliError</span> {} |
| |
| <span class="kw">impl</span> <span class="ident">Bernoulli</span> { |
| <span class="doccomment">/// Construct a new `Bernoulli` with the given probability of success `p`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// # Precision</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// For `p = 1.0`, the resulting distribution will always generate true.</span> |
| <span class="doccomment">/// For `p = 0.0`, the resulting distribution will always generate false.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// This method is accurate for any input `p` in the range `[0, 1]` which is</span> |
| <span class="doccomment">/// a multiple of 2<sup>-64</sup>. (Note that not all multiples of</span> |
| <span class="doccomment">/// 2<sup>-64</sup> in `[0, 1]` can be represented as a `f64`.)</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">p</span>: <span class="ident">f64</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Bernoulli</span>, <span class="ident">BernoulliError</span><span class="op">></span> { |
| <span class="kw">if</span> <span class="op">!</span>(<span class="number">0.0</span>..<span class="number">1.0</span>).<span class="ident">contains</span>(<span class="kw-2">&</span><span class="ident">p</span>) { |
| <span class="kw">if</span> <span class="ident">p</span> <span class="op">==</span> <span class="number">1.0</span> { |
| <span class="kw">return</span> <span class="prelude-val">Ok</span>(<span class="ident">Bernoulli</span> { <span class="ident">p_int</span>: <span class="ident">ALWAYS_TRUE</span> }); |
| } |
| <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">BernoulliError::InvalidProbability</span>); |
| } |
| <span class="prelude-val">Ok</span>(<span class="ident">Bernoulli</span> { |
| <span class="ident">p_int</span>: (<span class="ident">p</span> <span class="op">*</span> <span class="ident">SCALE</span>) <span class="kw">as</span> <span class="ident">u64</span>, |
| }) |
| } |
| |
| <span class="doccomment">/// Construct a new `Bernoulli` with the probability of success of</span> |
| <span class="doccomment">/// `numerator`-in-`denominator`. I.e. `new_ratio(2, 3)` will return</span> |
| <span class="doccomment">/// a `Bernoulli` with a 2-in-3 chance, or about 67%, of returning `true`.</span> |
| <span class="doccomment">///</span> |
| <span class="doccomment">/// return `true`. If `numerator == 0` it will always return `false`.</span> |
| <span class="doccomment">/// For `numerator > denominator` and `denominator == 0`, this returns an</span> |
| <span class="doccomment">/// error. Otherwise, for `numerator == denominator`, samples are always</span> |
| <span class="doccomment">/// true; for `numerator == 0` samples are always false.</span> |
| <span class="attribute">#[<span class="ident">inline</span>]</span> |
| <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">from_ratio</span>(<span class="ident">numerator</span>: <span class="ident">u32</span>, <span class="ident">denominator</span>: <span class="ident">u32</span>) -> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">Bernoulli</span>, <span class="ident">BernoulliError</span><span class="op">></span> { |
| <span class="kw">if</span> <span class="ident">numerator</span> <span class="op">></span> <span class="ident">denominator</span> <span class="op">|</span><span class="op">|</span> <span class="ident">denominator</span> <span class="op">==</span> <span class="number">0</span> { |
| <span class="kw">return</span> <span class="prelude-val">Err</span>(<span class="ident">BernoulliError::InvalidProbability</span>); |
| } |
| <span class="kw">if</span> <span class="ident">numerator</span> <span class="op">==</span> <span class="ident">denominator</span> { |
| <span class="kw">return</span> <span class="prelude-val">Ok</span>(<span class="ident">Bernoulli</span> { <span class="ident">p_int</span>: <span class="ident">ALWAYS_TRUE</span> }); |
| } |
| <span class="kw">let</span> <span class="ident">p_int</span> <span class="op">=</span> ((<span class="ident">f64::from</span>(<span class="ident">numerator</span>) <span class="op">/</span> <span class="ident">f64::from</span>(<span class="ident">denominator</span>)) <span class="op">*</span> <span class="ident">SCALE</span>) <span class="kw">as</span> <span class="ident">u64</span>; |
| <span class="prelude-val">Ok</span>(<span class="ident">Bernoulli</span> { <span class="ident">p_int</span> }) |
| } |
| } |
| |
| <span class="kw">impl</span> <span class="ident">Distribution</span><span class="op"><</span><span class="ident">bool</span><span class="op">></span> <span class="kw">for</span> <span class="ident">Bernoulli</span> { |
| <span class="attribute">#[<span class="ident">inline</span>]</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">bool</span> { |
| <span class="comment">// Make sure to always return true for p = 1.0.</span> |
| <span class="kw">if</span> <span class="self">self</span>.<span class="ident">p_int</span> <span class="op">==</span> <span class="ident">ALWAYS_TRUE</span> { |
| <span class="kw">return</span> <span class="bool-val">true</span>; |
| } |
| <span class="kw">let</span> <span class="ident">v</span>: <span class="ident">u64</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">gen</span>(); |
| <span class="ident">v</span> <span class="op"><</span> <span class="self">self</span>.<span class="ident">p_int</span> |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span> |
| <span class="kw">mod</span> <span class="ident">test</span> { |
| <span class="kw">use</span> <span class="ident"><span class="kw">super</span>::Bernoulli</span>; |
| <span class="kw">use</span> <span class="ident"><span class="kw">crate</span>::distributions::Distribution</span>; |
| <span class="kw">use</span> <span class="ident"><span class="kw">crate</span>::Rng</span>; |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span><span class="op">=</span><span class="string">"serde1"</span>)]</span> |
| <span class="kw">fn</span> <span class="ident">test_serializing_deserializing_bernoulli</span>() { |
| <span class="kw">let</span> <span class="ident">coin_flip</span> <span class="op">=</span> <span class="ident">Bernoulli::new</span>(<span class="number">0.5</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="ident">de_coin_flip</span> : <span class="ident">Bernoulli</span> <span class="op">=</span> <span class="ident">bincode::deserialize</span>(<span class="kw-2">&</span><span class="ident">bincode::serialize</span>(<span class="kw-2">&</span><span class="ident">coin_flip</span>).<span class="ident">unwrap</span>()).<span class="ident">unwrap</span>(); |
| |
| <span class="macro">assert_eq!</span>(<span class="ident">coin_flip</span>.<span class="ident">p_int</span>, <span class="ident">de_coin_flip</span>.<span class="ident">p_int</span>); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">test_trivial</span>() { |
| <span class="comment">// We prefer to be explicit here.</span> |
| <span class="attribute">#![<span class="ident">allow</span>(<span class="ident">clippy::bool_assert_comparison</span>)]</span> |
| |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">r</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>(<span class="number">1</span>); |
| <span class="kw">let</span> <span class="ident">always_false</span> <span class="op">=</span> <span class="ident">Bernoulli::new</span>(<span class="number">0.0</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="ident">always_true</span> <span class="op">=</span> <span class="ident">Bernoulli::new</span>(<span class="number">1.0</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="number">5</span> { |
| <span class="macro">assert_eq!</span>(<span class="ident">r</span>.<span class="ident">sample</span>::<span class="op"><</span><span class="ident">bool</span>, <span class="kw">_</span><span class="op">></span>(<span class="kw-2">&</span><span class="ident">always_false</span>), <span class="bool-val">false</span>); |
| <span class="macro">assert_eq!</span>(<span class="ident">r</span>.<span class="ident">sample</span>::<span class="op"><</span><span class="ident">bool</span>, <span class="kw">_</span><span class="op">></span>(<span class="kw-2">&</span><span class="ident">always_true</span>), <span class="bool-val">true</span>); |
| <span class="macro">assert_eq!</span>(<span class="ident">Distribution</span>::<span class="op"><</span><span class="ident">bool</span><span class="op">></span><span class="ident">::sample</span>(<span class="kw-2">&</span><span class="ident">always_false</span>, <span class="kw-2">&mut</span> <span class="ident">r</span>), <span class="bool-val">false</span>); |
| <span class="macro">assert_eq!</span>(<span class="ident">Distribution</span>::<span class="op"><</span><span class="ident">bool</span><span class="op">></span><span class="ident">::sample</span>(<span class="kw-2">&</span><span class="ident">always_true</span>, <span class="kw-2">&mut</span> <span class="ident">r</span>), <span class="bool-val">true</span>); |
| } |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">miri</span>, <span class="ident">ignore</span>)]</span> <span class="comment">// Miri is too slow</span> |
| <span class="kw">fn</span> <span class="ident">test_average</span>() { |
| <span class="kw">const</span> <span class="ident">P</span>: <span class="ident">f64</span> <span class="op">=</span> <span class="number">0.3</span>; |
| <span class="kw">const</span> <span class="ident">NUM</span>: <span class="ident">u32</span> <span class="op">=</span> <span class="number">3</span>; |
| <span class="kw">const</span> <span class="ident">DENOM</span>: <span class="ident">u32</span> <span class="op">=</span> <span class="number">10</span>; |
| <span class="kw">let</span> <span class="ident">d1</span> <span class="op">=</span> <span class="ident">Bernoulli::new</span>(<span class="ident">P</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="ident">d2</span> <span class="op">=</span> <span class="ident">Bernoulli::from_ratio</span>(<span class="ident">NUM</span>, <span class="ident">DENOM</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">const</span> <span class="ident">N</span>: <span class="ident">u32</span> <span class="op">=</span> <span class="number">100_000</span>; |
| |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">sum1</span>: <span class="ident">u32</span> <span class="op">=</span> <span class="number">0</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">sum2</span>: <span class="ident">u32</span> <span class="op">=</span> <span class="number">0</span>; |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>(<span class="number">2</span>); |
| <span class="kw">for</span> <span class="kw">_</span> <span class="kw">in</span> <span class="number">0</span>..<span class="ident">N</span> { |
| <span class="kw">if</span> <span class="ident">d1</span>.<span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">rng</span>) { |
| <span class="ident">sum1</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>; |
| } |
| <span class="kw">if</span> <span class="ident">d2</span>.<span class="ident">sample</span>(<span class="kw-2">&mut</span> <span class="ident">rng</span>) { |
| <span class="ident">sum2</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>; |
| } |
| } |
| <span class="kw">let</span> <span class="ident">avg1</span> <span class="op">=</span> (<span class="ident">sum1</span> <span class="kw">as</span> <span class="ident">f64</span>) <span class="op">/</span> (<span class="ident">N</span> <span class="kw">as</span> <span class="ident">f64</span>); |
| <span class="macro">assert!</span>((<span class="ident">avg1</span> <span class="op">-</span> <span class="ident">P</span>).<span class="ident">abs</span>() <span class="op"><</span> <span class="number">5e-3</span>); |
| |
| <span class="kw">let</span> <span class="ident">avg2</span> <span class="op">=</span> (<span class="ident">sum2</span> <span class="kw">as</span> <span class="ident">f64</span>) <span class="op">/</span> (<span class="ident">N</span> <span class="kw">as</span> <span class="ident">f64</span>); |
| <span class="macro">assert!</span>((<span class="ident">avg2</span> <span class="op">-</span> (<span class="ident">NUM</span> <span class="kw">as</span> <span class="ident">f64</span>) <span class="op">/</span> (<span class="ident">DENOM</span> <span class="kw">as</span> <span class="ident">f64</span>)).<span class="ident">abs</span>() <span class="op"><</span> <span class="number">5e-3</span>); |
| } |
| |
| <span class="attribute">#[<span class="ident">test</span>]</span> |
| <span class="kw">fn</span> <span class="ident">value_stability</span>() { |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rng</span> <span class="op">=</span> <span class="ident"><span class="kw">crate</span>::test::rng</span>(<span class="number">3</span>); |
| <span class="kw">let</span> <span class="ident">distr</span> <span class="op">=</span> <span class="ident">Bernoulli::new</span>(<span class="number">0.4532</span>).<span class="ident">unwrap</span>(); |
| <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buf</span> <span class="op">=</span> [<span class="bool-val">false</span>; <span class="number">10</span>]; |
| <span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="kw-2">&mut</span> <span class="ident">buf</span> { |
| <span class="kw-2">*</span><span class="ident">x</span> <span class="op">=</span> <span class="ident">rng</span>.<span class="ident">sample</span>(<span class="kw-2">&</span><span class="ident">distr</span>); |
| } |
| <span class="macro">assert_eq!</span>(<span class="ident">buf</span>, [ |
| <span class="bool-val">true</span>, <span class="bool-val">false</span>, <span class="bool-val">false</span>, <span class="bool-val">true</span>, <span class="bool-val">false</span>, <span class="bool-val">false</span>, <span class="bool-val">true</span>, <span class="bool-val">true</span>, <span class="bool-val">true</span>, <span class="bool-val">true</span> |
| ]); |
| } |
| } |
| </code></pre></div> |
| </section><section id="search" class="content hidden"></section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="rand" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.60.0-nightly (1bd4fdc94 2022-01-12)" ></div> |
| </body></html> |
