| <!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 `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/libm-0.2.7/src/math/sqrt.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>sqrt.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" href="../../../normalize.css"><link rel="stylesheet" href="../../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../../ayu.css" disabled><link rel="stylesheet" href="../../../dark.css" disabled><link rel="stylesheet" href="../../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../../storage.js"></script><script defer src="../../../source-script.js"></script><script defer src="../../../source-files.js"></script><script defer src="../../../main.js"></script><noscript><link rel="stylesheet" href="../../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../../favicon.svg"></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"><a class="sidebar-logo" href="../../../libm/index.html"><div class="logo-container"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../../libm/index.html"><img class="rust-logo" src="../../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-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> |
| <span id="215">215</span> |
| <span id="216">216</span> |
| <span id="217">217</span> |
| <span id="218">218</span> |
| <span id="219">219</span> |
| <span id="220">220</span> |
| <span id="221">221</span> |
| <span id="222">222</span> |
| <span id="223">223</span> |
| <span id="224">224</span> |
| <span id="225">225</span> |
| <span id="226">226</span> |
| <span id="227">227</span> |
| <span id="228">228</span> |
| <span id="229">229</span> |
| <span id="230">230</span> |
| <span id="231">231</span> |
| <span id="232">232</span> |
| <span id="233">233</span> |
| <span id="234">234</span> |
| <span id="235">235</span> |
| <span id="236">236</span> |
| <span id="237">237</span> |
| <span id="238">238</span> |
| <span id="239">239</span> |
| <span id="240">240</span> |
| <span id="241">241</span> |
| <span id="242">242</span> |
| <span id="243">243</span> |
| <span id="244">244</span> |
| <span id="245">245</span> |
| <span id="246">246</span> |
| <span id="247">247</span> |
| <span id="248">248</span> |
| <span id="249">249</span> |
| <span id="250">250</span> |
| <span id="251">251</span> |
| <span id="252">252</span> |
| <span id="253">253</span> |
| <span id="254">254</span> |
| <span id="255">255</span> |
| <span id="256">256</span> |
| <span id="257">257</span> |
| <span id="258">258</span> |
| <span id="259">259</span> |
| <span id="260">260</span> |
| <span id="261">261</span> |
| <span id="262">262</span> |
| <span id="263">263</span> |
| <span id="264">264</span> |
| <span id="265">265</span> |
| <span id="266">266</span> |
| <span id="267">267</span> |
| <span id="268">268</span> |
| <span id="269">269</span> |
| <span id="270">270</span> |
| <span id="271">271</span> |
| <span id="272">272</span> |
| <span id="273">273</span> |
| <span id="274">274</span> |
| <span id="275">275</span> |
| <span id="276">276</span> |
| <span id="277">277</span> |
| <span id="278">278</span> |
| <span id="279">279</span> |
| <span id="280">280</span> |
| </pre><pre class="rust"><code><span class="comment">/* origin: FreeBSD /usr/src/lib/msun/src/e_sqrt.c */ |
| /* |
| * ==================================================== |
| * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
| * |
| * Developed at SunSoft, a Sun Microsystems, Inc. business. |
| * Permission to use, copy, modify, and distribute this |
| * software is freely granted, provided that this notice |
| * is preserved. |
| * ==================================================== |
| */ |
| /* sqrt(x) |
| * Return correctly rounded sqrt. |
| * ------------------------------------------ |
| * | Use the hardware sqrt if you have one | |
| * ------------------------------------------ |
| * Method: |
| * Bit by bit method using integer arithmetic. (Slow, but portable) |
| * 1. Normalization |
| * Scale x to y in [1,4) with even powers of 2: |
| * find an integer k such that 1 <= (y=x*2^(2k)) < 4, then |
| * sqrt(x) = 2^k * sqrt(y) |
| * 2. Bit by bit computation |
| * Let q = sqrt(y) truncated to i bit after binary point (q = 1), |
| * i 0 |
| * i+1 2 |
| * s = 2*q , and y = 2 * ( y - q ). (1) |
| * i i i i |
| * |
| * To compute q from q , one checks whether |
| * i+1 i |
| * |
| * -(i+1) 2 |
| * (q + 2 ) <= y. (2) |
| * i |
| * -(i+1) |
| * If (2) is false, then q = q ; otherwise q = q + 2 . |
| * i+1 i i+1 i |
| * |
| * With some algebraic manipulation, it is not difficult to see |
| * that (2) is equivalent to |
| * -(i+1) |
| * s + 2 <= y (3) |
| * i i |
| * |
| * The advantage of (3) is that s and y can be computed by |
| * i i |
| * the following recurrence formula: |
| * if (3) is false |
| * |
| * s = s , y = y ; (4) |
| * i+1 i i+1 i |
| * |
| * otherwise, |
| * -i -(i+1) |
| * s = s + 2 , y = y - s - 2 (5) |
| * i+1 i i+1 i i |
| * |
| * One may easily use induction to prove (4) and (5). |
| * Note. Since the left hand side of (3) contain only i+2 bits, |
| * it does not necessary to do a full (53-bit) comparison |
| * in (3). |
| * 3. Final rounding |
| * After generating the 53 bits result, we compute one more bit. |
| * Together with the remainder, we can decide whether the |
| * result is exact, bigger than 1/2ulp, or less than 1/2ulp |
| * (it will never equal to 1/2ulp). |
| * The rounding mode can be detected by checking whether |
| * huge + tiny is equal to huge, and whether huge - tiny is |
| * equal to huge for some floating point number "huge" and "tiny". |
| * |
| * Special cases: |
| * sqrt(+-0) = +-0 ... exact |
| * sqrt(inf) = inf |
| * sqrt(-ve) = NaN ... with invalid signal |
| * sqrt(NaN) = NaN ... with invalid signal for signaling NaN |
| */ |
| |
| </span><span class="kw">use </span>core::f64; |
| |
| <span class="attribute">#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] |
| </span><span class="kw">pub fn </span>sqrt(x: f64) -> f64 { |
| <span class="comment">// On wasm32 we know that LLVM's intrinsic will compile to an optimized |
| // `f64.sqrt` native instruction, so we can leverage this for both code size |
| // and speed. |
| </span><span class="macro">llvm_intrinsically_optimized! </span>{ |
| <span class="attribute">#[cfg(target_arch = <span class="string">"wasm32"</span>)] </span>{ |
| <span class="kw">return if </span>x < <span class="number">0.0 </span>{ |
| f64::NAN |
| } <span class="kw">else </span>{ |
| <span class="kw">unsafe </span>{ ::core::intrinsics::sqrtf64(x) } |
| } |
| } |
| } |
| <span class="attribute">#[cfg(target_feature = <span class="string">"sse2"</span>)] |
| </span>{ |
| <span class="comment">// Note: This path is unlikely since LLVM will usually have already |
| // optimized sqrt calls into hardware instructions if sse2 is available, |
| // but if someone does end up here they'll apprected the speed increase. |
| </span><span class="attribute">#[cfg(target_arch = <span class="string">"x86"</span>)] |
| </span><span class="kw">use </span>core::arch::x86::<span class="kw-2">*</span>; |
| <span class="attribute">#[cfg(target_arch = <span class="string">"x86_64"</span>)] |
| </span><span class="kw">use </span>core::arch::x86_64::<span class="kw-2">*</span>; |
| <span class="kw">unsafe </span>{ |
| <span class="kw">let </span>m = _mm_set_sd(x); |
| <span class="kw">let </span>m_sqrt = _mm_sqrt_pd(m); |
| _mm_cvtsd_f64(m_sqrt) |
| } |
| } |
| <span class="attribute">#[cfg(not(target_feature = <span class="string">"sse2"</span>))] |
| </span>{ |
| <span class="kw">use </span>core::num::Wrapping; |
| |
| <span class="kw">const </span>TINY: f64 = <span class="number">1.0e-300</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>z: f64; |
| <span class="kw">let </span>sign: Wrapping<u32> = Wrapping(<span class="number">0x80000000</span>); |
| <span class="kw">let </span><span class="kw-2">mut </span>ix0: i32; |
| <span class="kw">let </span><span class="kw-2">mut </span>s0: i32; |
| <span class="kw">let </span><span class="kw-2">mut </span>q: i32; |
| <span class="kw">let </span><span class="kw-2">mut </span>m: i32; |
| <span class="kw">let </span><span class="kw-2">mut </span>t: i32; |
| <span class="kw">let </span><span class="kw-2">mut </span>i: i32; |
| <span class="kw">let </span><span class="kw-2">mut </span>r: Wrapping<u32>; |
| <span class="kw">let </span><span class="kw-2">mut </span>t1: Wrapping<u32>; |
| <span class="kw">let </span><span class="kw-2">mut </span>s1: Wrapping<u32>; |
| <span class="kw">let </span><span class="kw-2">mut </span>ix1: Wrapping<u32>; |
| <span class="kw">let </span><span class="kw-2">mut </span>q1: Wrapping<u32>; |
| |
| ix0 = (x.to_bits() >> <span class="number">32</span>) <span class="kw">as </span>i32; |
| ix1 = Wrapping(x.to_bits() <span class="kw">as </span>u32); |
| |
| <span class="comment">/* take care of Inf and NaN */ |
| </span><span class="kw">if </span>(ix0 & <span class="number">0x7ff00000</span>) == <span class="number">0x7ff00000 </span>{ |
| <span class="kw">return </span>x * x + x; <span class="comment">/* sqrt(NaN)=NaN, sqrt(+inf)=+inf, sqrt(-inf)=sNaN */ |
| </span>} |
| <span class="comment">/* take care of zero */ |
| </span><span class="kw">if </span>ix0 <= <span class="number">0 </span>{ |
| <span class="kw">if </span>((ix0 & !(sign.<span class="number">0 </span><span class="kw">as </span>i32)) | ix1.<span class="number">0 </span><span class="kw">as </span>i32) == <span class="number">0 </span>{ |
| <span class="kw">return </span>x; <span class="comment">/* sqrt(+-0) = +-0 */ |
| </span>} |
| <span class="kw">if </span>ix0 < <span class="number">0 </span>{ |
| <span class="kw">return </span>(x - x) / (x - x); <span class="comment">/* sqrt(-ve) = sNaN */ |
| </span>} |
| } |
| <span class="comment">/* normalize x */ |
| </span>m = ix0 >> <span class="number">20</span>; |
| <span class="kw">if </span>m == <span class="number">0 </span>{ |
| <span class="comment">/* subnormal x */ |
| </span><span class="kw">while </span>ix0 == <span class="number">0 </span>{ |
| m -= <span class="number">21</span>; |
| ix0 |= (ix1 >> <span class="number">11</span>).<span class="number">0 </span><span class="kw">as </span>i32; |
| ix1 <<= <span class="number">21</span>; |
| } |
| i = <span class="number">0</span>; |
| <span class="kw">while </span>(ix0 & <span class="number">0x00100000</span>) == <span class="number">0 </span>{ |
| i += <span class="number">1</span>; |
| ix0 <<= <span class="number">1</span>; |
| } |
| m -= i - <span class="number">1</span>; |
| ix0 |= (ix1 >> (<span class="number">32 </span>- i) <span class="kw">as </span>usize).<span class="number">0 </span><span class="kw">as </span>i32; |
| ix1 = ix1 << i <span class="kw">as </span>usize; |
| } |
| m -= <span class="number">1023</span>; <span class="comment">/* unbias exponent */ |
| </span>ix0 = (ix0 & <span class="number">0x000fffff</span>) | <span class="number">0x00100000</span>; |
| <span class="kw">if </span>(m & <span class="number">1</span>) == <span class="number">1 </span>{ |
| <span class="comment">/* odd m, double x to make it even */ |
| </span>ix0 += ix0 + ((ix1 & sign) >> <span class="number">31</span>).<span class="number">0 </span><span class="kw">as </span>i32; |
| ix1 += ix1; |
| } |
| m >>= <span class="number">1</span>; <span class="comment">/* m = [m/2] */ |
| |
| /* generate sqrt(x) bit by bit */ |
| </span>ix0 += ix0 + ((ix1 & sign) >> <span class="number">31</span>).<span class="number">0 </span><span class="kw">as </span>i32; |
| ix1 += ix1; |
| q = <span class="number">0</span>; <span class="comment">/* [q,q1] = sqrt(x) */ |
| </span>q1 = Wrapping(<span class="number">0</span>); |
| s0 = <span class="number">0</span>; |
| s1 = Wrapping(<span class="number">0</span>); |
| r = Wrapping(<span class="number">0x00200000</span>); <span class="comment">/* r = moving bit from right to left */ |
| |
| </span><span class="kw">while </span>r != Wrapping(<span class="number">0</span>) { |
| t = s0 + r.<span class="number">0 </span><span class="kw">as </span>i32; |
| <span class="kw">if </span>t <= ix0 { |
| s0 = t + r.<span class="number">0 </span><span class="kw">as </span>i32; |
| ix0 -= t; |
| q += r.<span class="number">0 </span><span class="kw">as </span>i32; |
| } |
| ix0 += ix0 + ((ix1 & sign) >> <span class="number">31</span>).<span class="number">0 </span><span class="kw">as </span>i32; |
| ix1 += ix1; |
| r >>= <span class="number">1</span>; |
| } |
| |
| r = sign; |
| <span class="kw">while </span>r != Wrapping(<span class="number">0</span>) { |
| t1 = s1 + r; |
| t = s0; |
| <span class="kw">if </span>t < ix0 || (t == ix0 && t1 <= ix1) { |
| s1 = t1 + r; |
| <span class="kw">if </span>(t1 & sign) == sign && (s1 & sign) == Wrapping(<span class="number">0</span>) { |
| s0 += <span class="number">1</span>; |
| } |
| ix0 -= t; |
| <span class="kw">if </span>ix1 < t1 { |
| ix0 -= <span class="number">1</span>; |
| } |
| ix1 -= t1; |
| q1 += r; |
| } |
| ix0 += ix0 + ((ix1 & sign) >> <span class="number">31</span>).<span class="number">0 </span><span class="kw">as </span>i32; |
| ix1 += ix1; |
| r >>= <span class="number">1</span>; |
| } |
| |
| <span class="comment">/* use floating add to find out rounding direction */ |
| </span><span class="kw">if </span>(ix0 <span class="kw">as </span>u32 | ix1.<span class="number">0</span>) != <span class="number">0 </span>{ |
| z = <span class="number">1.0 </span>- TINY; <span class="comment">/* raise inexact flag */ |
| </span><span class="kw">if </span>z >= <span class="number">1.0 </span>{ |
| z = <span class="number">1.0 </span>+ TINY; |
| <span class="kw">if </span>q1.<span class="number">0 </span>== <span class="number">0xffffffff </span>{ |
| q1 = Wrapping(<span class="number">0</span>); |
| q += <span class="number">1</span>; |
| } <span class="kw">else if </span>z > <span class="number">1.0 </span>{ |
| <span class="kw">if </span>q1.<span class="number">0 </span>== <span class="number">0xfffffffe </span>{ |
| q += <span class="number">1</span>; |
| } |
| q1 += Wrapping(<span class="number">2</span>); |
| } <span class="kw">else </span>{ |
| q1 += q1 & Wrapping(<span class="number">1</span>); |
| } |
| } |
| } |
| ix0 = (q >> <span class="number">1</span>) + <span class="number">0x3fe00000</span>; |
| ix1 = q1 >> <span class="number">1</span>; |
| <span class="kw">if </span>(q & <span class="number">1</span>) == <span class="number">1 </span>{ |
| ix1 |= sign; |
| } |
| ix0 += m << <span class="number">20</span>; |
| f64::from_bits((ix0 <span class="kw">as </span>u64) << <span class="number">32 </span>| ix1.<span class="number">0 </span><span class="kw">as </span>u64) |
| } |
| } |
| |
| <span class="attribute">#[cfg(test)] |
| </span><span class="kw">mod </span>tests { |
| <span class="kw">use super</span>::<span class="kw-2">*</span>; |
| <span class="kw">use </span>core::f64::<span class="kw-2">*</span>; |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>sanity_check() { |
| <span class="macro">assert_eq!</span>(sqrt(<span class="number">100.0</span>), <span class="number">10.0</span>); |
| <span class="macro">assert_eq!</span>(sqrt(<span class="number">4.0</span>), <span class="number">2.0</span>); |
| } |
| |
| <span class="doccomment">/// The spec: https://en.cppreference.com/w/cpp/numeric/math/sqrt |
| </span><span class="attribute">#[test] |
| </span><span class="kw">fn </span>spec_tests() { |
| <span class="comment">// Not Asserted: FE_INVALID exception is raised if argument is negative. |
| </span><span class="macro">assert!</span>(sqrt(-<span class="number">1.0</span>).is_nan()); |
| <span class="macro">assert!</span>(sqrt(NAN).is_nan()); |
| <span class="kw">for </span>f <span class="kw">in </span>[<span class="number">0.0</span>, -<span class="number">0.0</span>, INFINITY].iter().copied() { |
| <span class="macro">assert_eq!</span>(sqrt(f), f); |
| } |
| } |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>conformance_tests() { |
| <span class="kw">let </span>values = [<span class="number">3.14159265359</span>, <span class="number">10000.0</span>, f64::from_bits(<span class="number">0x0000000f</span>), INFINITY]; |
| <span class="kw">let </span>results = [ |
| <span class="number">4610661241675116657u64</span>, |
| <span class="number">4636737291354636288u64</span>, |
| <span class="number">2197470602079456986u64</span>, |
| <span class="number">9218868437227405312u64</span>, |
| ]; |
| |
| <span class="kw">for </span>i <span class="kw">in </span><span class="number">0</span>..values.len() { |
| <span class="kw">let </span>bits = f64::to_bits(sqrt(values[i])); |
| <span class="macro">assert_eq!</span>(results[i], bits); |
| } |
| } |
| } |
| </code></pre></div> |
| </section></div></main><div id="rustdoc-vars" data-root-path="../../../" data-current-crate="libm" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
