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 broadcast</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_to_all.html" title="Function all_to_all"> 11<link rel="next" href="gather.html" title="Function gather"> 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 broadcast</span></h2> 30<p>boost::mpi::broadcast — Broadcast a value from a root process to all other processes. </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">broadcast</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="identifier">T</span> <span class="special">&</span> value<span class="special">,</span> <span class="keyword">int</span> root<span class="special">)</span><span class="special">;</span> 38<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> 39 <span class="keyword">void</span> <span class="identifier">broadcast</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="identifier">T</span> <span class="special">*</span> values<span class="special">,</span> <span class="keyword">int</span> n<span class="special">,</span> <span class="keyword">int</span> root<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">broadcast</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> <a class="link" href="skeleton_proxy.html" title="Struct template skeleton_proxy">skeleton_proxy</a><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span> <span class="special">&</span> value<span class="special">,</span> 42 <span class="keyword">int</span> root<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">broadcast</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> <a class="link" href="skeleton_proxy.html" title="Struct template skeleton_proxy">skeleton_proxy</a><span class="special"><</span> <span class="identifier">T</span> <span class="special">></span> <span class="special">&</span> value<span class="special">,</span> 45 <span class="keyword">int</span> root<span class="special">)</span><span class="special">;</span></pre></div> 46<div class="refsect1"> 47<a name="id-1.3.27.7.5.7.4"></a><h2>Description</h2> 48<p><code class="computeroutput">broadcast</code> is a collective algorithm that transfers a value from an arbitrary <code class="computeroutput">root</code> process to every other process that is part of the given communicator. The <code class="computeroutput">broadcast</code> algorithm can transmit any Serializable value, values that have associated MPI data types, packed archives, skeletons, and the content of skeletons; see the <code class="computeroutput">send</code> primitive for communicators for a complete list. The type <code class="computeroutput">T</code> shall be the same for all processes that are a part of the communicator <code class="computeroutput">comm</code>, unless packed archives are being transferred: with packed archives, the root sends a <code class="computeroutput"><code class="computeroutput"><a class="link" href="packed_oarchive.html" title="Class packed_oarchive">packed_oarchive</a></code></code> or <code class="computeroutput">packed_skeleton_oarchive</code> whereas the other processes receive a <code class="computeroutput"><code class="computeroutput"><a class="link" href="packed_iarchive.html" title="Class packed_iarchive">packed_iarchive</a></code></code> or <code class="computeroutput">packed_skeleton_iarchve</code>, respectively.</p> 49<p>When the type <code class="computeroutput">T</code> has an associated MPI data type, this routine invokes <code class="computeroutput">MPI_Bcast</code> to perform the broadcast.</p> 50<p> 51</p> 52<div class="variablelist"><table border="0" class="variablelist compact"> 53<colgroup> 54<col align="left" valign="top"> 55<col> 56</colgroup> 57<tbody><tr> 58<td><p><span class="term">Parameters:</span></p></td> 59<td><div class="variablelist"><table border="0" class="variablelist compact"> 60<colgroup> 61<col align="left" valign="top"> 62<col> 63</colgroup> 64<tbody> 65<tr> 66<td><p><span class="term"><code class="computeroutput">comm</code></span></p></td> 67<td><p>The communicator over which the broadcast will occur.</p></td> 68</tr> 69<tr> 70<td><p><span class="term"><code class="computeroutput">root</code></span></p></td> 71<td><p>The rank/process ID of the process that will be transmitting the value. </p></td> 72</tr> 73<tr> 74<td><p><span class="term"><code class="computeroutput">value</code></span></p></td> 75<td><p>The value (or values, if <code class="computeroutput">n</code> is provided) to be transmitted (if the rank of <code class="computeroutput">comm</code> is equal to <code class="computeroutput">root</code>) or received (if the rank of <code class="computeroutput">comm</code> is not equal to <code class="computeroutput">root</code>). When the <code class="computeroutput">value</code> is a <code class="computeroutput"><code class="computeroutput"><a class="link" href="skeleton_proxy.html" title="Struct template skeleton_proxy">skeleton_proxy</a></code></code>, only the skeleton of the object will be broadcast. In this case, the <code class="computeroutput">root</code> will build a skeleton from the object help in the proxy and all of the non-roots will reshape the objects held in their proxies based on the skeleton sent from the root.</p></td> 76</tr> 77</tbody> 78</table></div></td> 79</tr></tbody> 80</table></div> 81</div> 82</div> 83<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 84<td align="left"></td> 85<td align="right"><div class="copyright-footer">Copyright © 2005-2007 Douglas Gregor, 86 Matthias Troyer, Trustees of Indiana University<p> 87 Distributed under the Boost Software License, Version 1.0. (See accompanying 88 file LICENSE_1_0.txt or copy at <ulink url="http://www.boost.org/LICENSE_1_0.txt"> 89 http://www.boost.org/LICENSE_1_0.txt </ulink>) 90 </p> 91</div></td> 92</tr></table> 93<hr> 94<div class="spirit-nav"> 95<a accesskey="p" href="all_to_all.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="gather.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 96</div> 97</body> 98</html> 99
