1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Function template indexed</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.Histogram"> 8<link rel="up" href="../../histogram/reference.html#header.boost.histogram.indexed_hpp" title="Header <boost/histogram/indexed.hpp>"> 9<link rel="prev" href="coverage.html" title="Type coverage"> 10<link rel="next" href="indexed_range.html" title="Class template indexed_range"> 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="../../../../../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="coverage.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../histogram/reference.html#header.boost.histogram.indexed_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="indexed_range.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="refentry"> 26<a name="boost.histogram.indexed"></a><div class="titlepage"></div> 27<div class="refnamediv"> 28<h2><span class="refentrytitle">Function template indexed</span></h2> 29<p>boost::histogram::indexed — Generates an indexed range of <a href="https://en.cppreference.com/w/cpp/named_req/ForwardIterator" target="_top">forward iterators</a> over the histogram cells.</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="../../histogram/reference.html#header.boost.histogram.indexed_hpp" title="Header <boost/histogram/indexed.hpp>">boost/histogram/indexed.hpp</a>> 33 34</span> 35<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Histogram<span class="special">></span> 36 <span class="keyword">auto</span> <span class="identifier">indexed</span><span class="special">(</span><span class="identifier">Histogram</span> <span class="special">&&</span> hist<span class="special">,</span> <span class="identifier">coverage</span> cov <span class="special">=</span> <span class="identifier">coverage</span><span class="special">::</span><span class="identifier">inner</span><span class="special">)</span><span class="special">;</span></pre></div> 37<div class="refsect1"> 38<a name="idm45113199813600"></a><h2>Description</h2> 39<p>Use this in a range-based for loop:</p> 40<pre class="programlisting"><span class="keyword">for</span> <span class="special">(</span><span class="keyword">auto</span><span class="special">&&</span> <span class="identifier">x</span> <span class="special">:</span> <span class="identifier">indexed</span><span class="special">(</span><span class="identifier">hist</span><span class="special">)</span><span class="special">)</span> <span class="special">{</span> <span class="special">...</span> <span class="special">}</span> 41</pre> 42<p>This generates an optimized loop which is nearly always faster than a hand-written loop over the histogram cells. The iterators dereference to an <code class="computeroutput"><a class="link" href="indexed_range/accessor.html" title="Class accessor">indexed_range::accessor</a></code>, which has methods to query the current indices and bins and acts like a pointer to the cell value. The returned iterators are forward iterators. They can be stored in a container, but may not be used after the life-time of the histogram ends.</p> 43<p> 44 45</p> 46<div class="variablelist"><table border="0" class="variablelist compact"> 47<colgroup> 48<col align="left" valign="top"> 49<col> 50</colgroup> 51<tbody> 52<tr> 53<td><p><span class="term">Parameters:</span></p></td> 54<td><div class="variablelist"><table border="0" class="variablelist compact"> 55<colgroup> 56<col align="left" valign="top"> 57<col> 58</colgroup> 59<tbody> 60<tr> 61<td><p><span class="term"><code class="computeroutput">cov</code></span></p></td> 62<td><p>Iterate over all or only inner bins (optional, default: inner). </p></td> 63</tr> 64<tr> 65<td><p><span class="term"><code class="computeroutput">hist</code></span></p></td> 66<td><p>Reference to the histogram. </p></td> 67</tr> 68</tbody> 69</table></div></td> 70</tr> 71<tr> 72<td><p><span class="term">Returns:</span></p></td> 73<td><p><a class="link" href="indexed_range.html" title="Class template indexed_range">indexed_range</a></p></td> 74</tr> 75</tbody> 76</table></div> 77</div> 78</div> 79<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 80<td align="left"></td> 81<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Hans 82 Dembinski<p> 83 Distributed under the Boost Software License, Version 1.0. (See accompanying 84 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 85 </p> 86</div></td> 87</tr></table> 88<hr> 89<div class="spirit-nav"> 90<a accesskey="p" href="coverage.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../histogram/reference.html#header.boost.histogram.indexed_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="indexed_range.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 91</div> 92</body> 93</html> 94
