1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Tutorial</title> 5<link rel="stylesheet" href="../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../index.html" title="Chapter 1. Boost.Compute"> 8<link rel="up" href="../index.html" title="Chapter 1. Boost.Compute"> 9<link rel="prev" href="design.html" title="Design"> 10<link rel="next" href="advanced_topics.html" title="Advanced Topics"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="design.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><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="advanced_topics.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h2 class="title" style="clear: both"> 27<a name="boost_compute.tutorial"></a><a class="link" href="tutorial.html" title="Tutorial">Tutorial</a> 28</h2></div></div></div> 29<div class="toc"><dl class="toc"> 30<dt><span class="section"><a href="tutorial.html#boost_compute.tutorial.hello_world">Hello World</a></span></dt> 31<dt><span class="section"><a href="tutorial.html#boost_compute.tutorial.transferring_data">Transferring 32 Data</a></span></dt> 33<dt><span class="section"><a href="tutorial.html#boost_compute.tutorial.transforming_data">Transforming 34 Data</a></span></dt> 35</dl></div> 36<div class="section"> 37<div class="titlepage"><div><div><h3 class="title"> 38<a name="boost_compute.tutorial.hello_world"></a><a class="link" href="tutorial.html#boost_compute.tutorial.hello_world" title="Hello World">Hello World</a> 39</h3></div></div></div> 40<p> 41 The hello world example gives a simple application that prints the name of 42 the default compute device on the system. 43 </p> 44<p> 45 The <code class="computeroutput">boost::compute::system</code> 46 class provides access to the OpenCL platforms and devices present on the 47 host system. 48 </p> 49<p> 50 Compute devices are represented with the <code class="computeroutput">device</code> 51 class. 52 </p> 53<p> 54</p> 55<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> 56 57<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">compute</span><span class="special">/</span><span class="identifier">core</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 58 59<span class="keyword">namespace</span> <span class="identifier">compute</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">compute</span><span class="special">;</span> 60 61<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> 62<span class="special">{</span> 63 <span class="comment">// get the default device</span> 64 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">device</span> <span class="identifier">device</span> <span class="special">=</span> <span class="identifier">compute</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">default_device</span><span class="special">();</span> 65 66 <span class="comment">// print the device's name and platform</span> 67 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"hello from "</span> <span class="special"><<</span> <span class="identifier">device</span><span class="special">.</span><span class="identifier">name</span><span class="special">();</span> 68 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">" (platform: "</span> <span class="special"><<</span> <span class="identifier">device</span><span class="special">.</span><span class="identifier">platform</span><span class="special">().</span><span class="identifier">name</span><span class="special">()</span> <span class="special"><<</span> <span class="string">")"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 69 70 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> 71<span class="special">}</span> 72</pre> 73<p> 74 </p> 75</div> 76<div class="section"> 77<div class="titlepage"><div><div><h3 class="title"> 78<a name="boost_compute.tutorial.transferring_data"></a><a class="link" href="tutorial.html#boost_compute.tutorial.transferring_data" title="Transferring Data">Transferring 79 Data</a> 80</h3></div></div></div> 81<p> 82 Before any computation occurs, data must be transferred from the host to 83 the compute device. The generic <code class="computeroutput"><a class="link" href="../boost/compute/copy.html" title="Function template copy">copy()</a></code> 84 function provides a simple interface for transfering data and the generic 85 <code class="computeroutput"><a class="link" href="../boost/compute/vector.html" title="Class template vector">vector<T></a></code> class 86 provides a container for storing data on a compute device. 87 </p> 88<p> 89 The following example shows how to transfer data from an array on the host 90 to a <code class="computeroutput"><a class="link" href="../boost/compute/vector.html" title="Class template vector">vector<T></a></code> 91 on the device and then back to a separate <code class="computeroutput"><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></code> 92 on the host. At the end of the example both <code class="computeroutput"><span class="identifier">host_array</span></code> 93 and <code class="computeroutput"><span class="identifier">host_vector</span></code> contain the 94 same values which were copied through the memory on the compute device. 95 </p> 96<p> 97</p> 98<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">vector</span><span class="special">></span> 99 100<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">compute</span><span class="special">/</span><span class="identifier">algorithm</span><span class="special">/</span><span class="identifier">copy</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 101<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">compute</span><span class="special">/</span><span class="identifier">container</span><span class="special">/</span><span class="identifier">vector</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 102 103<span class="keyword">namespace</span> <span class="identifier">compute</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">compute</span><span class="special">;</span> 104 105<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> 106<span class="special">{</span> 107 <span class="comment">// get default device and setup context</span> 108 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">device</span> <span class="identifier">device</span> <span class="special">=</span> <span class="identifier">compute</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">default_device</span><span class="special">();</span> 109 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">context</span> <span class="identifier">context</span><span class="special">(</span><span class="identifier">device</span><span class="special">);</span> 110 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">command_queue</span> <span class="identifier">queue</span><span class="special">(</span><span class="identifier">context</span><span class="special">,</span> <span class="identifier">device</span><span class="special">);</span> 111 112 <span class="comment">// create data array on host</span> 113 <span class="keyword">int</span> <span class="identifier">host_data</span><span class="special">[]</span> <span class="special">=</span> <span class="special">{</span> <span class="number">1</span><span class="special">,</span> <span class="number">3</span><span class="special">,</span> <span class="number">5</span><span class="special">,</span> <span class="number">7</span><span class="special">,</span> <span class="number">9</span> <span class="special">};</span> 114 115 <span class="comment">// create vector on device</span> 116 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">device_vector</span><span class="special">(</span><span class="number">5</span><span class="special">,</span> <span class="identifier">context</span><span class="special">);</span> 117 118 <span class="comment">// copy from host to device</span> 119 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">copy</span><span class="special">(</span> 120 <span class="identifier">host_data</span><span class="special">,</span> <span class="identifier">host_data</span> <span class="special">+</span> <span class="number">5</span><span class="special">,</span> <span class="identifier">device_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">queue</span> 121 <span class="special">);</span> 122 123 <span class="comment">// create vector on host</span> 124 <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">host_vector</span><span class="special">(</span><span class="number">5</span><span class="special">);</span> 125 126 <span class="comment">// copy data back to host</span> 127 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">copy</span><span class="special">(</span> 128 <span class="identifier">device_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">device_vector</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span> <span class="identifier">host_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">queue</span> 129 <span class="special">);</span> 130 131 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> 132<span class="special">}</span> 133</pre> 134<p> 135 </p> 136</div> 137<div class="section"> 138<div class="titlepage"><div><div><h3 class="title"> 139<a name="boost_compute.tutorial.transforming_data"></a><a class="link" href="tutorial.html#boost_compute.tutorial.transforming_data" title="Transforming Data">Transforming 140 Data</a> 141</h3></div></div></div> 142<p> 143 The following example shows how to calculate the square-root of a vector 144 of <code class="computeroutput"><span class="keyword">float</span></code>s on a compute device 145 using the <code class="computeroutput"><a class="link" href="../boost/compute/transform.html" title="Function transform">transform()</a></code> 146 function. 147 </p> 148<p> 149</p> 150<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">vector</span><span class="special">></span> 151<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">algorithm</span><span class="special">></span> 152 153<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">compute</span><span class="special">/</span><span class="identifier">algorithm</span><span class="special">/</span><span class="identifier">transform</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 154<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">compute</span><span class="special">/</span><span class="identifier">container</span><span class="special">/</span><span class="identifier">vector</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 155<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">compute</span><span class="special">/</span><span class="identifier">functional</span><span class="special">/</span><span class="identifier">math</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 156 157<span class="keyword">namespace</span> <span class="identifier">compute</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">compute</span><span class="special">;</span> 158 159<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> 160<span class="special">{</span> 161 <span class="comment">// get default device and setup context</span> 162 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">device</span> <span class="identifier">device</span> <span class="special">=</span> <span class="identifier">compute</span><span class="special">::</span><span class="identifier">system</span><span class="special">::</span><span class="identifier">default_device</span><span class="special">();</span> 163 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">context</span> <span class="identifier">context</span><span class="special">(</span><span class="identifier">device</span><span class="special">);</span> 164 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">command_queue</span> <span class="identifier">queue</span><span class="special">(</span><span class="identifier">context</span><span class="special">,</span> <span class="identifier">device</span><span class="special">);</span> 165 166 <span class="comment">// generate random data on the host</span> 167 <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">float</span><span class="special">></span> <span class="identifier">host_vector</span><span class="special">(</span><span class="number">10000</span><span class="special">);</span> 168 <span class="identifier">std</span><span class="special">::</span><span class="identifier">generate</span><span class="special">(</span><span class="identifier">host_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">host_vector</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span> <span class="identifier">rand</span><span class="special">);</span> 169 170 <span class="comment">// create a vector on the device</span> 171 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">float</span><span class="special">></span> <span class="identifier">device_vector</span><span class="special">(</span><span class="identifier">host_vector</span><span class="special">.</span><span class="identifier">size</span><span class="special">(),</span> <span class="identifier">context</span><span class="special">);</span> 172 173 <span class="comment">// transfer data from the host to the device</span> 174 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">copy</span><span class="special">(</span> 175 <span class="identifier">host_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">host_vector</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span> <span class="identifier">device_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">queue</span> 176 <span class="special">);</span> 177 178 <span class="comment">// calculate the square-root of each element in-place</span> 179 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">transform</span><span class="special">(</span> 180 <span class="identifier">device_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> 181 <span class="identifier">device_vector</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span> 182 <span class="identifier">device_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> 183 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">sqrt</span><span class="special"><</span><span class="keyword">float</span><span class="special">>(),</span> 184 <span class="identifier">queue</span> 185 <span class="special">);</span> 186 187 <span class="comment">// copy values back to the host</span> 188 <span class="identifier">compute</span><span class="special">::</span><span class="identifier">copy</span><span class="special">(</span> 189 <span class="identifier">device_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">device_vector</span><span class="special">.</span><span class="identifier">end</span><span class="special">(),</span> <span class="identifier">host_vector</span><span class="special">.</span><span class="identifier">begin</span><span class="special">(),</span> <span class="identifier">queue</span> 190 <span class="special">);</span> 191 192 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> 193<span class="special">}</span> 194</pre> 195<p> 196 </p> 197</div> 198</div> 199<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 200<td align="left"></td> 201<td align="right"><div class="copyright-footer">Copyright © 2013, 2014 Kyle Lutz<p> 202 Distributed under the Boost Software License, Version 1.0. (See accompanying 203 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 204 </p> 205</div></td> 206</tr></table> 207<hr> 208<div class="spirit-nav"> 209<a accesskey="p" href="design.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../index.html"><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="advanced_topics.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a> 210</div> 211</body> 212</html> 213
