| <!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="Parallel extensions for mutable slices."><meta name="keywords" content="rust, rustlang, rust-lang, ParallelSliceMut"><title>ParallelSliceMut in rayon::slice - 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" 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="sidebar-items.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 trait"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle">☰</button><a class="sidebar-logo" href="../../rayon/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2></h2></nav><nav class="sidebar"><a class="sidebar-logo" href="../../rayon/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a><h2 class="location"><a href="#">ParallelSliceMut</a></h2><div class="sidebar-elems"><section><h3><a href="#required-methods">Required Methods</a></h3><ul class="block"><li><a href="#tymethod.as_parallel_slice_mut">as_parallel_slice_mut</a></li></ul><h3><a href="#provided-methods">Provided Methods</a></h3><ul class="block"><li><a href="#method.par_chunks_exact_mut">par_chunks_exact_mut</a></li><li><a href="#method.par_chunks_mut">par_chunks_mut</a></li><li><a href="#method.par_rchunks_exact_mut">par_rchunks_exact_mut</a></li><li><a href="#method.par_rchunks_mut">par_rchunks_mut</a></li><li><a href="#method.par_sort">par_sort</a></li><li><a href="#method.par_sort_by">par_sort_by</a></li><li><a href="#method.par_sort_by_cached_key">par_sort_by_cached_key</a></li><li><a href="#method.par_sort_by_key">par_sort_by_key</a></li><li><a href="#method.par_sort_unstable">par_sort_unstable</a></li><li><a href="#method.par_sort_unstable_by">par_sort_unstable_by</a></li><li><a href="#method.par_sort_unstable_by_key">par_sort_unstable_by_key</a></li><li><a href="#method.par_split_mut">par_split_mut</a></li></ul><h3><a href="#foreign-impls">Implementations on Foreign Types</a></h3><ul class="block"><li><a href="#impl-ParallelSliceMut%3CT%3E-for-%5BT%5D">[T]</a></li></ul><h3><a href="#implementors">Implementors</a></h3></section><h2><a href="index.html">In rayon::slice</a></h2></div></nav><main><div class="width-limiter"><nav class="sub"><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="main-heading"><h1 class="fqn">Trait <a href="../index.html">rayon</a>::<wbr><a href="index.html">slice</a>::<wbr><a class="trait" href="#">ParallelSliceMut</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></h1><span class="out-of-band"><a class="srclink" href="../../src/rayon/slice/mod.rs.html#163-662">source</a> · <a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">[<span class="inner">−</span>]</a></span></div><div class="item-decl"><pre class="rust trait"><code>pub trait ParallelSliceMut<T: Send> { |
| <details class="rustdoc-toggle type-contents-toggle"><summary class="hideme"><span>Show 13 methods</span></summary> fn <a href="#tymethod.as_parallel_slice_mut" class="fnname">as_parallel_slice_mut</a>(&mut self) -> &mut [T]; |
| |
| fn <a href="#method.par_split_mut" class="fnname">par_split_mut</a><P>(&mut self, separator: P) -> <a class="struct" href="struct.SplitMut.html" title="struct rayon::slice::SplitMut">SplitMut</a><'_, T, P><br> <span class="where">where<br> P: Fn(&T) -> bool + Sync + Send</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.par_chunks_mut" class="fnname">par_chunks_mut</a>(&mut self, chunk_size: usize) -> <a class="struct" href="struct.ChunksMut.html" title="struct rayon::slice::ChunksMut">ChunksMut</a><'_, T> { ... } |
| <span class="item-spacer"></span> fn <a href="#method.par_chunks_exact_mut" class="fnname">par_chunks_exact_mut</a>(<br> &mut self,<br> chunk_size: usize<br> ) -> <a class="struct" href="struct.ChunksExactMut.html" title="struct rayon::slice::ChunksExactMut">ChunksExactMut</a><'_, T> { ... } |
| <span class="item-spacer"></span> fn <a href="#method.par_rchunks_mut" class="fnname">par_rchunks_mut</a>(&mut self, chunk_size: usize) -> <a class="struct" href="struct.RChunksMut.html" title="struct rayon::slice::RChunksMut">RChunksMut</a><'_, T> { ... } |
| <span class="item-spacer"></span> fn <a href="#method.par_rchunks_exact_mut" class="fnname">par_rchunks_exact_mut</a>(<br> &mut self,<br> chunk_size: usize<br> ) -> <a class="struct" href="struct.RChunksExactMut.html" title="struct rayon::slice::RChunksExactMut">RChunksExactMut</a><'_, T> { ... } |
| <span class="item-spacer"></span> fn <a href="#method.par_sort" class="fnname">par_sort</a>(&mut self)<br> <span class="where">where<br> T: Ord</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.par_sort_by" class="fnname">par_sort_by</a><F>(&mut self, compare: F)<br> <span class="where">where<br> F: Fn(&T, &T) -> Ordering + Sync</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.par_sort_by_key" class="fnname">par_sort_by_key</a><K, F>(&mut self, f: F)<br> <span class="where">where<br> K: Ord,<br> F: Fn(&T) -> K + Sync</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.par_sort_by_cached_key" class="fnname">par_sort_by_cached_key</a><K, F>(&mut self, f: F)<br> <span class="where">where<br> F: Fn(&T) -> K + Sync,<br> K: Ord + Send</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.par_sort_unstable" class="fnname">par_sort_unstable</a>(&mut self)<br> <span class="where">where<br> T: Ord</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.par_sort_unstable_by" class="fnname">par_sort_unstable_by</a><F>(&mut self, compare: F)<br> <span class="where">where<br> F: Fn(&T, &T) -> Ordering + Sync</span>, |
| { ... } |
| <span class="item-spacer"></span> fn <a href="#method.par_sort_unstable_by_key" class="fnname">par_sort_unstable_by_key</a><K, F>(&mut self, f: F)<br> <span class="where">where<br> K: Ord,<br> F: Fn(&T) -> K + Sync</span>, |
| { ... } |
| </details>}</code></pre></div><details class="rustdoc-toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Parallel extensions for mutable slices.</p> |
| </div></details><h2 id="required-methods" class="small-section-header">Required Methods<a href="#required-methods" class="anchor"></a></h2><div class="methods"><details class="rustdoc-toggle method-toggle" open><summary><section id="tymethod.as_parallel_slice_mut" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#166">source</a><h4 class="code-header">fn <a href="#tymethod.as_parallel_slice_mut" class="fnname">as_parallel_slice_mut</a>(&mut self) -> &mut [T]</h4></section></summary><div class="docblock"><p>Returns a plain mutable slice, which is used to implement the rest of |
| the parallel methods.</p> |
| </div></details></div><h2 id="provided-methods" class="small-section-header">Provided Methods<a href="#provided-methods" class="anchor"></a></h2><div class="methods"><details class="rustdoc-toggle method-toggle" open><summary><section id="method.par_split_mut" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#180-188">source</a><h4 class="code-header">fn <a href="#method.par_split_mut" class="fnname">par_split_mut</a><P>(&mut self, separator: P) -> <a class="struct" href="struct.SplitMut.html" title="struct rayon::slice::SplitMut">SplitMut</a><'_, T, P><span class="where fmt-newline">where<br> P: Fn(&T) -> bool + Sync + Send,</span></h4></section></summary><div class="docblock"><p>Returns a parallel iterator over mutable subslices separated by |
| elements that match the separator.</p> |
| <h5 id="examples"><a href="#examples">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>array = [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">0</span>, <span class="number">2</span>, <span class="number">4</span>, <span class="number">8</span>, <span class="number">0</span>, <span class="number">3</span>, <span class="number">6</span>, <span class="number">9</span>]; |
| array.par_split_mut(|i| <span class="kw-2">*</span>i == <span class="number">0</span>) |
| .for_each(|slice| slice.reverse()); |
| <span class="macro">assert_eq!</span>(array, [<span class="number">3</span>, <span class="number">2</span>, <span class="number">1</span>, <span class="number">0</span>, <span class="number">8</span>, <span class="number">4</span>, <span class="number">2</span>, <span class="number">0</span>, <span class="number">9</span>, <span class="number">6</span>, <span class="number">3</span>]);</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.par_chunks_mut" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#207-210">source</a><h4 class="code-header">fn <a href="#method.par_chunks_mut" class="fnname">par_chunks_mut</a>(&mut self, chunk_size: usize) -> <a class="struct" href="struct.ChunksMut.html" title="struct rayon::slice::ChunksMut">ChunksMut</a><'_, T></h4></section></summary><div class="docblock"><p>Returns a parallel iterator over at most <code>chunk_size</code> elements of |
| <code>self</code> at a time. The chunks are mutable and do not overlap.</p> |
| <p>If the number of elements in the iterator is not divisible by |
| <code>chunk_size</code>, the last chunk may be shorter than <code>chunk_size</code>. All |
| other chunks will have that exact length.</p> |
| <h5 id="examples-1"><a href="#examples-1">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>array = [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>]; |
| array.par_chunks_mut(<span class="number">2</span>) |
| .for_each(|slice| slice.reverse()); |
| <span class="macro">assert_eq!</span>(array, [<span class="number">2</span>, <span class="number">1</span>, <span class="number">4</span>, <span class="number">3</span>, <span class="number">5</span>]);</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.par_chunks_exact_mut" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#229-232">source</a><h4 class="code-header">fn <a href="#method.par_chunks_exact_mut" class="fnname">par_chunks_exact_mut</a>(&mut self, chunk_size: usize) -> <a class="struct" href="struct.ChunksExactMut.html" title="struct rayon::slice::ChunksExactMut">ChunksExactMut</a><'_, T></h4></section></summary><div class="docblock"><p>Returns a parallel iterator over <code>chunk_size</code> elements of |
| <code>self</code> at a time. The chunks are mutable and do not overlap.</p> |
| <p>If <code>chunk_size</code> does not divide the length of the slice, then the |
| last up to <code>chunk_size-1</code> elements will be omitted and can be |
| retrieved from the remainder function of the iterator.</p> |
| <h5 id="examples-2"><a href="#examples-2">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>array = [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>]; |
| array.par_chunks_exact_mut(<span class="number">3</span>) |
| .for_each(|slice| slice.reverse()); |
| <span class="macro">assert_eq!</span>(array, [<span class="number">3</span>, <span class="number">2</span>, <span class="number">1</span>, <span class="number">4</span>, <span class="number">5</span>]);</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.par_rchunks_mut" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#251-254">source</a><h4 class="code-header">fn <a href="#method.par_rchunks_mut" class="fnname">par_rchunks_mut</a>(&mut self, chunk_size: usize) -> <a class="struct" href="struct.RChunksMut.html" title="struct rayon::slice::RChunksMut">RChunksMut</a><'_, T></h4></section></summary><div class="docblock"><p>Returns a parallel iterator over at most <code>chunk_size</code> elements of <code>self</code> at a time, |
| starting at the end. The chunks are mutable and do not overlap.</p> |
| <p>If the number of elements in the iterator is not divisible by |
| <code>chunk_size</code>, the last chunk may be shorter than <code>chunk_size</code>. All |
| other chunks will have that exact length.</p> |
| <h5 id="examples-3"><a href="#examples-3">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>array = [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>]; |
| array.par_rchunks_mut(<span class="number">2</span>) |
| .for_each(|slice| slice.reverse()); |
| <span class="macro">assert_eq!</span>(array, [<span class="number">1</span>, <span class="number">3</span>, <span class="number">2</span>, <span class="number">5</span>, <span class="number">4</span>]);</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.par_rchunks_exact_mut" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#273-276">source</a><h4 class="code-header">fn <a href="#method.par_rchunks_exact_mut" class="fnname">par_rchunks_exact_mut</a>(&mut self, chunk_size: usize) -> <a class="struct" href="struct.RChunksExactMut.html" title="struct rayon::slice::RChunksExactMut">RChunksExactMut</a><'_, T></h4></section></summary><div class="docblock"><p>Returns a parallel iterator over <code>chunk_size</code> elements of <code>self</code> at a time, |
| starting at the end. The chunks are mutable and do not overlap.</p> |
| <p>If <code>chunk_size</code> does not divide the length of the slice, then the |
| last up to <code>chunk_size-1</code> elements will be omitted and can be |
| retrieved from the remainder function of the iterator.</p> |
| <h5 id="examples-4"><a href="#examples-4">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| <span class="kw">let </span><span class="kw-2">mut </span>array = [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>]; |
| array.par_rchunks_exact_mut(<span class="number">3</span>) |
| .for_each(|slice| slice.reverse()); |
| <span class="macro">assert_eq!</span>(array, [<span class="number">1</span>, <span class="number">2</span>, <span class="number">5</span>, <span class="number">4</span>, <span class="number">3</span>]);</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.par_sort" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#311-316">source</a><h4 class="code-header">fn <a href="#method.par_sort" class="fnname">par_sort</a>(&mut self)<span class="where fmt-newline">where<br> T: Ord,</span></h4></section></summary><div class="docblock"><p>Sorts the slice in parallel.</p> |
| <p>This sort is stable (i.e., does not reorder equal elements) and <em>O</em>(<em>n</em> * log(<em>n</em>)) worst-case.</p> |
| <p>When applicable, unstable sorting is preferred because it is generally faster than stable |
| sorting and it doesn’t allocate auxiliary memory. |
| See <a href="#method.par_sort_unstable"><code>par_sort_unstable</code></a>.</p> |
| <h5 id="current-implementation"><a href="#current-implementation">Current implementation</a></h5> |
| <p>The current algorithm is an adaptive merge sort inspired by |
| <a href="https://en.wikipedia.org/wiki/Timsort">timsort</a>. |
| It is designed to be very fast in cases where the slice is nearly sorted, or consists of |
| two or more sorted sequences concatenated one after another.</p> |
| <p>Also, it allocates temporary storage the same size as <code>self</code>, but for very short slices a |
| non-allocating insertion sort is used instead.</p> |
| <p>In order to sort the slice in parallel, the slice is first divided into smaller chunks and |
| all chunks are sorted in parallel. Then, adjacent chunks that together form non-descending |
| or descending runs are concatenated. Finally, the remaining chunks are merged together using |
| parallel subdivision of chunks and parallel merge operation.</p> |
| <h5 id="examples-5"><a href="#examples-5">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>v = [-<span class="number">5</span>, <span class="number">4</span>, <span class="number">1</span>, -<span class="number">3</span>, <span class="number">2</span>]; |
| |
| v.par_sort(); |
| <span class="macro">assert_eq!</span>(v, [-<span class="number">5</span>, -<span class="number">3</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">4</span>]);</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.par_sort_by" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#372-379">source</a><h4 class="code-header">fn <a href="#method.par_sort_by" class="fnname">par_sort_by</a><F>(&mut self, compare: F)<span class="where fmt-newline">where<br> F: Fn(&T, &T) -> Ordering + Sync,</span></h4></section></summary><div class="docblock"><p>Sorts the slice in parallel with a comparator function.</p> |
| <p>This sort is stable (i.e., does not reorder equal elements) and <em>O</em>(<em>n</em> * log(<em>n</em>)) worst-case.</p> |
| <p>The comparator function must define a total ordering for the elements in the slice. If |
| the ordering is not total, the order of the elements is unspecified. An order is a |
| total order if it is (for all <code>a</code>, <code>b</code> and <code>c</code>):</p> |
| <ul> |
| <li>total and antisymmetric: exactly one of <code>a < b</code>, <code>a == b</code> or <code>a > b</code> is true, and</li> |
| <li>transitive, <code>a < b</code> and <code>b < c</code> implies <code>a < c</code>. The same must hold for both <code>==</code> and <code>></code>.</li> |
| </ul> |
| <p>For example, while [<code>f64</code>] doesn’t implement [<code>Ord</code>] because <code>NaN != NaN</code>, we can use |
| <code>partial_cmp</code> as our sort function when we know the slice doesn’t contain a <code>NaN</code>.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>floats = [<span class="number">5f64</span>, <span class="number">4.0</span>, <span class="number">1.0</span>, <span class="number">3.0</span>, <span class="number">2.0</span>]; |
| floats.par_sort_by(|a, b| a.partial_cmp(b).unwrap()); |
| <span class="macro">assert_eq!</span>(floats, [<span class="number">1.0</span>, <span class="number">2.0</span>, <span class="number">3.0</span>, <span class="number">4.0</span>, <span class="number">5.0</span>]);</code></pre></div> |
| <p>When applicable, unstable sorting is preferred because it is generally faster than stable |
| sorting and it doesn’t allocate auxiliary memory. |
| See <a href="#method.par_sort_unstable_by"><code>par_sort_unstable_by</code></a>.</p> |
| <h5 id="current-implementation-1"><a href="#current-implementation-1">Current implementation</a></h5> |
| <p>The current algorithm is an adaptive merge sort inspired by |
| <a href="https://en.wikipedia.org/wiki/Timsort">timsort</a>. |
| It is designed to be very fast in cases where the slice is nearly sorted, or consists of |
| two or more sorted sequences concatenated one after another.</p> |
| <p>Also, it allocates temporary storage the same size as <code>self</code>, but for very short slices a |
| non-allocating insertion sort is used instead.</p> |
| <p>In order to sort the slice in parallel, the slice is first divided into smaller chunks and |
| all chunks are sorted in parallel. Then, adjacent chunks that together form non-descending |
| or descending runs are concatenated. Finally, the remaining chunks are merged together using |
| parallel subdivision of chunks and parallel merge operation.</p> |
| <h5 id="examples-6"><a href="#examples-6">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>v = [<span class="number">5</span>, <span class="number">4</span>, <span class="number">1</span>, <span class="number">3</span>, <span class="number">2</span>]; |
| v.par_sort_by(|a, b| a.cmp(b)); |
| <span class="macro">assert_eq!</span>(v, [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>]); |
| |
| <span class="comment">// reverse sorting |
| </span>v.par_sort_by(|a, b| b.cmp(a)); |
| <span class="macro">assert_eq!</span>(v, [<span class="number">5</span>, <span class="number">4</span>, <span class="number">3</span>, <span class="number">2</span>, <span class="number">1</span>]);</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.par_sort_by_key" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#419-425">source</a><h4 class="code-header">fn <a href="#method.par_sort_by_key" class="fnname">par_sort_by_key</a><K, F>(&mut self, f: F)<span class="where fmt-newline">where<br> K: Ord,<br> F: Fn(&T) -> K + Sync,</span></h4></section></summary><div class="docblock"><p>Sorts the slice in parallel with a key extraction function.</p> |
| <p>This sort is stable (i.e., does not reorder equal elements) and <em>O</em>(<em>m</em> * <em>n</em> * log(<em>n</em>)) |
| worst-case, where the key function is <em>O</em>(<em>m</em>).</p> |
| <p>For expensive key functions (e.g. functions that are not simple property accesses or |
| basic operations), <a href="#method.par_sort_by_cached_key"><code>par_sort_by_cached_key</code></a> is likely to |
| be significantly faster, as it does not recompute element keys.</p> |
| <p>When applicable, unstable sorting is preferred because it is generally faster than stable |
| sorting and it doesn’t allocate auxiliary memory. |
| See <a href="#method.par_sort_unstable_by_key"><code>par_sort_unstable_by_key</code></a>.</p> |
| <h5 id="current-implementation-2"><a href="#current-implementation-2">Current implementation</a></h5> |
| <p>The current algorithm is an adaptive merge sort inspired by |
| <a href="https://en.wikipedia.org/wiki/Timsort">timsort</a>. |
| It is designed to be very fast in cases where the slice is nearly sorted, or consists of |
| two or more sorted sequences concatenated one after another.</p> |
| <p>Also, it allocates temporary storage the same size as <code>self</code>, but for very short slices a |
| non-allocating insertion sort is used instead.</p> |
| <p>In order to sort the slice in parallel, the slice is first divided into smaller chunks and |
| all chunks are sorted in parallel. Then, adjacent chunks that together form non-descending |
| or descending runs are concatenated. Finally, the remaining chunks are merged together using |
| parallel subdivision of chunks and parallel merge operation.</p> |
| <h5 id="examples-7"><a href="#examples-7">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>v = [-<span class="number">5i32</span>, <span class="number">4</span>, <span class="number">1</span>, -<span class="number">3</span>, <span class="number">2</span>]; |
| |
| v.par_sort_by_key(|k| k.abs()); |
| <span class="macro">assert_eq!</span>(v, [<span class="number">1</span>, <span class="number">2</span>, -<span class="number">3</span>, <span class="number">4</span>, -<span class="number">5</span>]);</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.par_sort_by_cached_key" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#467-516">source</a><h4 class="code-header">fn <a href="#method.par_sort_by_cached_key" class="fnname">par_sort_by_cached_key</a><K, F>(&mut self, f: F)<span class="where fmt-newline">where<br> F: Fn(&T) -> K + Sync,<br> K: Ord + Send,</span></h4></section></summary><div class="docblock"><p>Sorts the slice in parallel with a key extraction function.</p> |
| <p>During sorting, the key function is called at most once per element, by using |
| temporary storage to remember the results of key evaluation. |
| The key function is called in parallel, so the order of calls is completely unspecified.</p> |
| <p>This sort is stable (i.e., does not reorder equal elements) and <em>O</em>(<em>m</em> * <em>n</em> + <em>n</em> * log(<em>n</em>)) |
| worst-case, where the key function is <em>O</em>(<em>m</em>).</p> |
| <p>For simple key functions (e.g., functions that are property accesses or |
| basic operations), <a href="#method.par_sort_by_key"><code>par_sort_by_key</code></a> is likely to be |
| faster.</p> |
| <h5 id="current-implementation-3"><a href="#current-implementation-3">Current implementation</a></h5> |
| <p>The current algorithm is based on <a href="https://github.com/orlp/pdqsort">pattern-defeating quicksort</a> by Orson Peters, |
| which combines the fast average case of randomized quicksort with the fast worst case of |
| heapsort, while achieving linear time on slices with certain patterns. It uses some |
| randomization to avoid degenerate cases, but with a fixed seed to always provide |
| deterministic behavior.</p> |
| <p>In the worst case, the algorithm allocates temporary storage in a <code>Vec<(K, usize)></code> the |
| length of the slice.</p> |
| <p>All quicksorts work in two stages: partitioning into two halves followed by recursive |
| calls. The partitioning phase is sequential, but the two recursive calls are performed in |
| parallel. Finally, after sorting the cached keys, the item positions are updated sequentially.</p> |
| <h5 id="examples-8"><a href="#examples-8">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>v = [-<span class="number">5i32</span>, <span class="number">4</span>, <span class="number">32</span>, -<span class="number">3</span>, <span class="number">2</span>]; |
| |
| v.par_sort_by_cached_key(|k| k.to_string()); |
| <span class="macro">assert!</span>(v == [-<span class="number">3</span>, -<span class="number">5</span>, <span class="number">2</span>, <span class="number">32</span>, <span class="number">4</span>]);</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.par_sort_unstable" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#550-555">source</a><h4 class="code-header">fn <a href="#method.par_sort_unstable" class="fnname">par_sort_unstable</a>(&mut self)<span class="where fmt-newline">where<br> T: Ord,</span></h4></section></summary><div class="docblock"><p>Sorts the slice in parallel, but might not preserve the order of equal elements.</p> |
| <p>This sort is unstable (i.e., may reorder equal elements), in-place |
| (i.e., does not allocate), and <em>O</em>(<em>n</em> * log(<em>n</em>)) worst-case.</p> |
| <h5 id="current-implementation-4"><a href="#current-implementation-4">Current implementation</a></h5> |
| <p>The current algorithm is based on <a href="https://github.com/orlp/pdqsort">pattern-defeating quicksort</a> by Orson Peters, |
| which combines the fast average case of randomized quicksort with the fast worst case of |
| heapsort, while achieving linear time on slices with certain patterns. It uses some |
| randomization to avoid degenerate cases, but with a fixed seed to always provide |
| deterministic behavior.</p> |
| <p>It is typically faster than stable sorting, except in a few special cases, e.g., when the |
| slice consists of several concatenated sorted sequences.</p> |
| <p>All quicksorts work in two stages: partitioning into two halves followed by recursive |
| calls. The partitioning phase is sequential, but the two recursive calls are performed in |
| parallel.</p> |
| <h5 id="examples-9"><a href="#examples-9">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>v = [-<span class="number">5</span>, <span class="number">4</span>, <span class="number">1</span>, -<span class="number">3</span>, <span class="number">2</span>]; |
| |
| v.par_sort_unstable(); |
| <span class="macro">assert_eq!</span>(v, [-<span class="number">5</span>, -<span class="number">3</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">4</span>]);</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.par_sort_unstable_by" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#611-618">source</a><h4 class="code-header">fn <a href="#method.par_sort_unstable_by" class="fnname">par_sort_unstable_by</a><F>(&mut self, compare: F)<span class="where fmt-newline">where<br> F: Fn(&T, &T) -> Ordering + Sync,</span></h4></section></summary><div class="docblock"><p>Sorts the slice in parallel with a comparator function, but might not preserve the order of |
| equal elements.</p> |
| <p>This sort is unstable (i.e., may reorder equal elements), in-place |
| (i.e., does not allocate), and <em>O</em>(<em>n</em> * log(<em>n</em>)) worst-case.</p> |
| <p>The comparator function must define a total ordering for the elements in the slice. If |
| the ordering is not total, the order of the elements is unspecified. An order is a |
| total order if it is (for all <code>a</code>, <code>b</code> and <code>c</code>):</p> |
| <ul> |
| <li>total and antisymmetric: exactly one of <code>a < b</code>, <code>a == b</code> or <code>a > b</code> is true, and</li> |
| <li>transitive, <code>a < b</code> and <code>b < c</code> implies <code>a < c</code>. The same must hold for both <code>==</code> and <code>></code>.</li> |
| </ul> |
| <p>For example, while [<code>f64</code>] doesn’t implement [<code>Ord</code>] because <code>NaN != NaN</code>, we can use |
| <code>partial_cmp</code> as our sort function when we know the slice doesn’t contain a <code>NaN</code>.</p> |
| |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>floats = [<span class="number">5f64</span>, <span class="number">4.0</span>, <span class="number">1.0</span>, <span class="number">3.0</span>, <span class="number">2.0</span>]; |
| floats.par_sort_unstable_by(|a, b| a.partial_cmp(b).unwrap()); |
| <span class="macro">assert_eq!</span>(floats, [<span class="number">1.0</span>, <span class="number">2.0</span>, <span class="number">3.0</span>, <span class="number">4.0</span>, <span class="number">5.0</span>]);</code></pre></div> |
| <h5 id="current-implementation-5"><a href="#current-implementation-5">Current implementation</a></h5> |
| <p>The current algorithm is based on <a href="https://github.com/orlp/pdqsort">pattern-defeating quicksort</a> by Orson Peters, |
| which combines the fast average case of randomized quicksort with the fast worst case of |
| heapsort, while achieving linear time on slices with certain patterns. It uses some |
| randomization to avoid degenerate cases, but with a fixed seed to always provide |
| deterministic behavior.</p> |
| <p>It is typically faster than stable sorting, except in a few special cases, e.g., when the |
| slice consists of several concatenated sorted sequences.</p> |
| <p>All quicksorts work in two stages: partitioning into two halves followed by recursive |
| calls. The partitioning phase is sequential, but the two recursive calls are performed in |
| parallel.</p> |
| <h5 id="examples-10"><a href="#examples-10">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>v = [<span class="number">5</span>, <span class="number">4</span>, <span class="number">1</span>, <span class="number">3</span>, <span class="number">2</span>]; |
| v.par_sort_unstable_by(|a, b| a.cmp(b)); |
| <span class="macro">assert_eq!</span>(v, [<span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>]); |
| |
| <span class="comment">// reverse sorting |
| </span>v.par_sort_unstable_by(|a, b| b.cmp(a)); |
| <span class="macro">assert_eq!</span>(v, [<span class="number">5</span>, <span class="number">4</span>, <span class="number">3</span>, <span class="number">2</span>, <span class="number">1</span>]);</code></pre></div> |
| </div></details><details class="rustdoc-toggle method-toggle" open><summary><section id="method.par_sort_unstable_by_key" class="method has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#655-661">source</a><h4 class="code-header">fn <a href="#method.par_sort_unstable_by_key" class="fnname">par_sort_unstable_by_key</a><K, F>(&mut self, f: F)<span class="where fmt-newline">where<br> K: Ord,<br> F: Fn(&T) -> K + Sync,</span></h4></section></summary><div class="docblock"><p>Sorts the slice in parallel with a key extraction function, but might not preserve the order |
| of equal elements.</p> |
| <p>This sort is unstable (i.e., may reorder equal elements), in-place |
| (i.e., does not allocate), and <em>O</em>(m * <em>n</em> * log(<em>n</em>)) worst-case, |
| where the key function is <em>O</em>(<em>m</em>).</p> |
| <h5 id="current-implementation-6"><a href="#current-implementation-6">Current implementation</a></h5> |
| <p>The current algorithm is based on <a href="https://github.com/orlp/pdqsort">pattern-defeating quicksort</a> by Orson Peters, |
| which combines the fast average case of randomized quicksort with the fast worst case of |
| heapsort, while achieving linear time on slices with certain patterns. It uses some |
| randomization to avoid degenerate cases, but with a fixed seed to always provide |
| deterministic behavior.</p> |
| <p>Due to its key calling strategy, <code>par_sort_unstable_by_key</code> is likely to be slower than |
| <a href="#method.par_sort_by_cached_key"><code>par_sort_by_cached_key</code></a> in cases where the key function |
| is expensive.</p> |
| <p>All quicksorts work in two stages: partitioning into two halves followed by recursive |
| calls. The partitioning phase is sequential, but the two recursive calls are performed in |
| parallel.</p> |
| <h5 id="examples-11"><a href="#examples-11">Examples</a></h5> |
| <div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>rayon::prelude::<span class="kw-2">*</span>; |
| |
| <span class="kw">let </span><span class="kw-2">mut </span>v = [-<span class="number">5i32</span>, <span class="number">4</span>, <span class="number">1</span>, -<span class="number">3</span>, <span class="number">2</span>]; |
| |
| v.par_sort_unstable_by_key(|k| k.abs()); |
| <span class="macro">assert_eq!</span>(v, [<span class="number">1</span>, <span class="number">2</span>, -<span class="number">3</span>, <span class="number">4</span>, -<span class="number">5</span>]);</code></pre></div> |
| </div></details></div><h2 id="foreign-impls" class="small-section-header">Implementations on Foreign Types<a href="#foreign-impls" class="anchor"></a></h2><details class="rustdoc-toggle implementors-toggle"><summary><section id="impl-ParallelSliceMut%3CT%3E-for-%5BT%5D" class="impl has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#664-669">source</a><a href="#impl-ParallelSliceMut%3CT%3E-for-%5BT%5D" class="anchor"></a><h3 class="code-header">impl<T: Send> <a class="trait" href="trait.ParallelSliceMut.html" title="trait rayon::slice::ParallelSliceMut">ParallelSliceMut</a><T> for [T]</h3></section></summary><div class="impl-items"><section id="method.as_parallel_slice_mut" class="method trait-impl has-srclink"><a class="srclink rightside" href="../../src/rayon/slice/mod.rs.html#666-668">source</a><a href="#method.as_parallel_slice_mut" class="anchor"></a><h4 class="code-header">fn <a href="#tymethod.as_parallel_slice_mut" class="fnname">as_parallel_slice_mut</a>(&mut self) -> &mut [T]</h4></section></div></details><h2 id="implementors" class="small-section-header">Implementors<a href="#implementors" class="anchor"></a></h2><div id="implementors-list"></div><script src="../../implementors/rayon/slice/trait.ParallelSliceMut.js" data-ignore-extern-crates="core" async></script></section></div></main><div id="rustdoc-vars" data-root-path="../../" data-current-crate="rayon" data-themes="ayu,dark,light" data-resource-suffix="" data-rustdoc-version="1.66.0-nightly (5c8bff74b 2022-10-21)" ></div></body></html> |
