1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>Function all_to_all</title> 6<link rel="stylesheet" href="../../../../doc/src/boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 8<link rel="home" href="../../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> 9<link rel="up" href="../../mpi/reference.html#header.boost.mpi.collectives_hpp" title="Header <boost/mpi/collectives.hpp>"> 10<link rel="prev" href="all_reduce.html" title="Function all_reduce"> 11<link rel="next" href="broadcast.html" title="Function broadcast"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table cellpadding="2" width="100%"><tr> 15<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../boost.png"></td> 16<td 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class="refnamediv"> 29<h2><span class="refentrytitle">Function all_to_all</span></h2> 30<p>boost::mpi::all_to_all — Send data from every process to every other process. </p> 31</div> 32<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 33<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="../../mpi/reference.html#header.boost.mpi.collectives_hpp" title="Header <boost/mpi/collectives.hpp>">boost/mpi/collectives.hpp</a>> 34 35</span> 36<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> 37 <span class="keyword">void</span> <span class="identifier">all_to_all</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="communicator.html" title="Class communicator">communicator</a> <span class="special">&</span> comm<span class="special">,</span> 38 <span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span> <span class="special">&</span> in_values<span class="special">,</span> 39 <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span> <span class="special">&</span> out_values<span class="special">)</span><span class="special">;</span> 40<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> 41 <span class="keyword">void</span> <span class="identifier">all_to_all</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="communicator.html" title="Class communicator">communicator</a> <span class="special">&</span> comm<span class="special">,</span> <span class="keyword">const</span> <span class="identifier">T</span> <span class="special">*</span> in_values<span class="special">,</span> 42 <span class="identifier">T</span> <span class="special">*</span> out_values<span class="special">)</span><span class="special">;</span> 43<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> 44 <span class="keyword">void</span> <span class="identifier">all_to_all</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="communicator.html" title="Class communicator">communicator</a> <span class="special">&</span> comm<span class="special">,</span> 45 <span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span> <span class="special">&</span> in_values<span class="special">,</span> <span class="keyword">int</span> n<span class="special">,</span> 46 <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span> <span class="special">&</span> out_values<span class="special">)</span><span class="special">;</span> 47<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> 48 <span class="keyword">void</span> <span class="identifier">all_to_all</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="communicator.html" title="Class communicator">communicator</a> <span class="special">&</span> comm<span class="special">,</span> <span class="keyword">const</span> <span class="identifier">T</span> <span class="special">*</span> in_values<span class="special">,</span> <span class="keyword">int</span> n<span class="special">,</span> 49 <span class="identifier">T</span> <span class="special">*</span> out_values<span class="special">)</span><span class="special">;</span></pre></div> 50<div class="refsect1"> 51<a name="id-1.3.27.7.5.6.4"></a><h2>Description</h2> 52<p><code class="computeroutput">all_to_all</code> is a collective algorithm that transmits <code class="computeroutput">p</code> values from every process to every other process. On process i, jth value of the <code class="computeroutput">in_values</code> vector is sent to process j and placed in the ith position of the <code class="computeroutput">out_values</code> vector in process <code class="computeroutput">j</code>. The type <code class="computeroutput">T</code> of the values may be any type that is serializable or has an associated MPI data type. If <code class="computeroutput">n</code> is provided, then arrays of <code class="computeroutput">n</code> values will be transferred from one process to another.</p> 53<p>When the type <code class="computeroutput">T</code> has an associated MPI data type, this routine invokes <code class="computeroutput">MPI_Alltoall</code> to scatter the values.</p> 54<p> 55</p> 56<div class="variablelist"><table border="0" class="variablelist compact"> 57<colgroup> 58<col align="left" valign="top"> 59<col> 60</colgroup> 61<tbody><tr> 62<td><p><span class="term">Parameters:</span></p></td> 63<td><div class="variablelist"><table border="0" class="variablelist compact"> 64<colgroup> 65<col align="left" valign="top"> 66<col> 67</colgroup> 68<tbody> 69<tr> 70<td><p><span class="term"><code class="computeroutput">comm</code></span></p></td> 71<td><p>The communicator over which the all-to-all communication will occur.</p></td> 72</tr> 73<tr> 74<td><p><span class="term"><code class="computeroutput">in_values</code></span></p></td> 75<td><p>A vector or pointer to storage that contains the values to send to each process, indexed by the process ID number.</p></td> 76</tr> 77<tr> 78<td><p><span class="term"><code class="computeroutput">out_values</code></span></p></td> 79<td><p>A vector or pointer to storage that will be updated to contain the values received from other processes. The jth value in <code class="computeroutput">out_values</code> will come from the procss with rank j. </p></td> 80</tr> 81</tbody> 82</table></div></td> 83</tr></tbody> 84</table></div> 85</div> 86</div> 87<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 88<td align="left"></td> 89<td align="right"><div class="copyright-footer">Copyright © 2005-2007 Douglas Gregor, 90 Matthias Troyer, Trustees of Indiana University<p> 91 Distributed under the Boost Software License, Version 1.0. (See accompanying 92 file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt"> 93 http://www.boost.org/LICENSE_1_0.txt </ulink>) 94 </p> 95</div></td> 96</tr></table> 97<hr> 98<div class="spirit-nav"> 99<a accesskey="p" href="all_reduce.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../mpi/reference.html#header.boost.mpi.collectives_hpp"><img src="../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="broadcast.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 100</div> 101</body> 102</html> 103
