1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Function exclusive_scan</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. 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20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="equal_range.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../boost_compute/reference.html#header.boost.compute.algorithm.exclusive_scan_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="fill.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="refentry"> 26<a name="boost.compute.exclusive_scan"></a><div class="titlepage"></div> 27<div class="refnamediv"> 28<h2><span class="refentrytitle">Function exclusive_scan</span></h2> 29<p>boost::compute::exclusive_scan</p> 30</div> 31<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 32<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="../../boost_compute/reference.html#header.boost.compute.algorithm.exclusive_scan_hpp" title="Header <boost/compute/algorithm/exclusive_scan.hpp>">boost/compute/algorithm/exclusive_scan.hpp</a>> 33 34</span> 35<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> InputIterator<span class="special">,</span> <span class="keyword">typename</span> OutputIterator<span class="special">,</span> <span class="keyword">typename</span> T<span class="special">,</span> 36 <span class="keyword">typename</span> BinaryOperator<span class="special">></span> 37 <span class="identifier">OutputIterator</span> 38 <span class="identifier">exclusive_scan</span><span class="special">(</span><span class="identifier">InputIterator</span> first<span class="special">,</span> <span class="identifier">InputIterator</span> last<span class="special">,</span> 39 <span class="identifier">OutputIterator</span> result<span class="special">,</span> <span class="identifier">T</span> init<span class="special">,</span> <span class="identifier">BinaryOperator</span> binary_op<span class="special">,</span> 40 <span class="identifier">command_queue</span> <span class="special">&</span> queue <span class="special">=</span> <span class="identifier">system</span><span class="special">::</span><span class="identifier">default_queue</span><span class="special">(</span><span class="special">)</span><span class="special">)</span><span class="special">;</span> 41<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> InputIterator<span class="special">,</span> <span class="keyword">typename</span> OutputIterator<span class="special">,</span> <span class="keyword">typename</span> T<span class="special">></span> 42 <span class="identifier">OutputIterator</span> 43 <span class="identifier">exclusive_scan</span><span class="special">(</span><span class="identifier">InputIterator</span> first<span class="special">,</span> <span class="identifier">InputIterator</span> last<span class="special">,</span> 44 <span class="identifier">OutputIterator</span> result<span class="special">,</span> <span class="identifier">T</span> init<span class="special">,</span> 45 <span class="identifier">command_queue</span> <span class="special">&</span> queue <span class="special">=</span> <span class="identifier">system</span><span class="special">::</span><span class="identifier">default_queue</span><span class="special">(</span><span class="special">)</span><span class="special">)</span><span class="special">;</span> 46<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> InputIterator<span class="special">,</span> <span class="keyword">typename</span> OutputIterator<span class="special">></span> 47 <span class="identifier">OutputIterator</span> 48 <span class="identifier">exclusive_scan</span><span class="special">(</span><span class="identifier">InputIterator</span> first<span class="special">,</span> <span class="identifier">InputIterator</span> last<span class="special">,</span> 49 <span class="identifier">OutputIterator</span> result<span class="special">,</span> 50 <span class="identifier">command_queue</span> <span class="special">&</span> queue <span class="special">=</span> <span class="identifier">system</span><span class="special">::</span><span class="identifier">default_queue</span><span class="special">(</span><span class="special">)</span><span class="special">)</span><span class="special">;</span></pre></div> 51<div class="refsect1"> 52<a name="idm45849522379104"></a><h2>Description</h2> 53<p>Performs an exclusive scan of the elements in the range [<code class="computeroutput">first</code>, <code class="computeroutput">last</code>) and stores the results in the range beginning at <code class="computeroutput">result</code>.</p> 54<p>Each element in the output is assigned to the sum of all the previous values in the input.</p> 55<p> 56 57The default operation is to add the elements up.</p> 58<pre class="programlisting"></pre> 59<p> But different associative operation can be specified as <code class="computeroutput">binary_op</code> instead (e.g., multiplication, maximum, minimum). Also value used to initialized the scan sequence can be specified.</p> 60<pre class="programlisting"></pre> 61<p> Space complexity on GPUs: \Omega(n)<br> 62 Space complexity on GPUs when <code class="computeroutput">first</code> == <code class="computeroutput">result:</code> \Omega(2n)<br> 63 Space complexity on CPUs: \Omega(1)</p> 64<p><span class="bold"><strong>See Also:</strong></span></p> 65<p>inclusive_scan() </p> 66<p> 67</p> 68<p> 69</p> 70<div class="variablelist"><table border="0" class="variablelist compact"> 71<colgroup> 72<col align="left" valign="top"> 73<col> 74</colgroup> 75<tbody> 76<tr> 77<td><p><span class="term">Parameters:</span></p></td> 78<td><div class="variablelist"><table border="0" class="variablelist compact"> 79<colgroup> 80<col align="left" valign="top"> 81<col> 82</colgroup> 83<tbody> 84<tr> 85<td><p><span class="term"><code class="computeroutput">binary_op</code></span></p></td> 86<td><p>associative binary operator </p></td> 87</tr> 88<tr> 89<td><p><span class="term"><code class="computeroutput">first</code></span></p></td> 90<td><p>first element in the range to scan </p></td> 91</tr> 92<tr> 93<td><p><span class="term"><code class="computeroutput">init</code></span></p></td> 94<td><p>value used to initialize the scan sequence </p></td> 95</tr> 96<tr> 97<td><p><span class="term"><code class="computeroutput">last</code></span></p></td> 98<td><p>last element in the range to scan </p></td> 99</tr> 100<tr> 101<td><p><span class="term"><code class="computeroutput">queue</code></span></p></td> 102<td><p>command queue to perform the operation</p></td> 103</tr> 104<tr> 105<td><p><span class="term"><code class="computeroutput">result</code></span></p></td> 106<td><p>first element in the result range </p></td> 107</tr> 108</tbody> 109</table></div></td> 110</tr> 111<tr> 112<td><p><span class="term">Returns:</span></p></td> 113<td><p><code class="computeroutput">OutputIterator</code> to the end of the result range</p></td> 114</tr> 115</tbody> 116</table></div> 117</div> 118</div> 119<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 120<td align="left"></td> 121<td align="right"><div class="copyright-footer">Copyright © 2013, 2014 Kyle Lutz<p> 122 Distributed under the Boost Software License, Version 1.0. (See accompanying 123 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>) 124 </p> 125</div></td> 126</tr></table> 127<hr> 128<div class="spirit-nav"> 129<a accesskey="p" href="equal_range.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../boost_compute/reference.html#header.boost.compute.algorithm.exclusive_scan_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="fill.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 130</div> 131</body> 132</html> 133
