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_gather</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="cartesian_dimensions.html" title="Function cartesian_dimensions"> 11<link rel="next" href="all_reduce.html" title="Function all_reduce"> 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" 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name="boost.mpi.all_gather"></a><div class="titlepage"></div> 28<div class="refnamediv"> 29<h2><span class="refentrytitle">Function all_gather</span></h2> 30<p>boost::mpi::all_gather — Gather the values stored at every process into vectors of values from each 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_gather</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_value<span class="special">,</span> 38 <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> 39<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> 40 <span class="keyword">void</span> <span class="identifier">all_gather</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_value<span class="special">,</span> 41 <span class="identifier">T</span> <span class="special">*</span> out_values<span class="special">)</span><span class="special">;</span> 42<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> 43 <span class="keyword">void</span> <span class="identifier">all_gather</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> 44 <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> 45<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> 46 <span class="keyword">void</span> <span class="identifier">all_gather</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> 47 <span class="identifier">T</span> <span class="special">*</span> out_values<span class="special">)</span><span class="special">;</span></pre></div> 48<div class="refsect1"> 49<a name="id-1.3.27.7.5.4.4"></a><h2>Description</h2> 50<p><code class="computeroutput">all_gather</code> is a collective algorithm that collects the values stored at each process into a vector of values indexed by the process number they came from. The type <code class="computeroutput">T</code> of the values may be any type that is serializable or has an associated MPI data type.</p> 51<p>When the type <code class="computeroutput">T</code> has an associated MPI data type, this routine invokes <code class="computeroutput">MPI_Allgather</code> to gather the values.</p> 52<p> 53</p> 54<div class="variablelist"><table border="0" class="variablelist compact"> 55<colgroup> 56<col align="left" valign="top"> 57<col> 58</colgroup> 59<tbody><tr> 60<td><p><span class="term">Parameters:</span></p></td> 61<td><div class="variablelist"><table border="0" class="variablelist compact"> 62<colgroup> 63<col align="left" valign="top"> 64<col> 65</colgroup> 66<tbody> 67<tr> 68<td><p><span class="term"><code class="computeroutput">comm</code></span></p></td> 69<td><p>The communicator over which the all-gather will occur.</p></td> 70</tr> 71<tr> 72<td><p><span class="term"><code class="computeroutput">in_value</code></span></p></td> 73<td><p>The value to be transmitted by each process. To gather an array of values, <code class="computeroutput">in_values</code> points to the <code class="computeroutput">n</code> local values to be transmitted.</p></td> 74</tr> 75<tr> 76<td><p><span class="term"><code class="computeroutput">out_values</code></span></p></td> 77<td><p>A vector or pointer to storage that will be populated with the values from each process, indexed by the process ID number. If it is a vector, the vector will be resized accordingly. </p></td> 78</tr> 79</tbody> 80</table></div></td> 81</tr></tbody> 82</table></div> 83</div> 84</div> 85<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 86<td align="left"></td> 87<td align="right"><div class="copyright-footer">Copyright © 2005-2007 Douglas Gregor, 88 Matthias Troyer, Trustees of Indiana University<p> 89 Distributed under the Boost Software License, Version 1.0. (See accompanying 90 file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt"> 91 http://www.boost.org/LICENSE_1_0.txt </ulink>) 92 </p> 93</div></td> 94</tr></table> 95<hr> 96<div class="spirit-nav"> 97<a accesskey="p" href="cartesian_dimensions.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="all_reduce.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 98</div> 99</body> 100</html> 101