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>Class template variate_generator</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="../boost_random/reference.html#header.boost.random.variate_generator_hpp" title="Header <boost/random/variate_generator.hpp>"> 10<link rel="prev" href="random/uniform_smallint/param_type.html" title="Class param_type"> 11<link rel="next" href="random/weibull_distribution.html" title="Class template weibull_distribution"> 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 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25</div> 26<div class="refentry"> 27<a name="boost.variate_generator"></a><div class="titlepage"></div> 28<div class="refnamediv"> 29<h2><span class="refentrytitle">Class template variate_generator</span></h2> 30<p>boost::variate_generator</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="../boost_random/reference.html#header.boost.random.variate_generator_hpp" title="Header <boost/random/variate_generator.hpp>">boost/random/variate_generator.hpp</a>> 34 35</span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> Engine<span class="special">,</span> <span class="keyword">typename</span> Distribution<span class="special">></span> 36<span class="keyword">class</span> <a class="link" href="variate_generator.html" title="Class template variate_generator">variate_generator</a> <span class="special">{</span> 37<span class="keyword">public</span><span class="special">:</span> 38 <span class="comment">// types</span> 39 <span class="keyword">typedef</span> <span class="identifier">helper_type</span><span class="special">::</span><span class="identifier">value_type</span> <a name="boost.variate_generator.engine_value_type"></a><span class="identifier">engine_value_type</span><span class="special">;</span> 40 <span class="keyword">typedef</span> <span class="identifier">Engine</span> <a name="boost.variate_generator.engine_type"></a><span class="identifier">engine_type</span><span class="special">;</span> 41 <span class="keyword">typedef</span> <span class="identifier">Distribution</span> <a name="boost.variate_generator.distribution_type"></a><span class="identifier">distribution_type</span><span class="special">;</span> 42 <span class="keyword">typedef</span> <span class="identifier">Distribution</span><span class="special">::</span><span class="identifier">result_type</span> <a name="boost.variate_generator.result_type"></a><span class="identifier">result_type</span><span class="special">;</span> 43 44 <span class="comment">// <a class="link" href="variate_generator.html#boost.variate_generatorconstruct-copy-destruct">construct/copy/destruct</a></span> 45 <a class="link" href="variate_generator.html#id-1_3_34_5_6_50_1_1_8-bb"><span class="identifier">variate_generator</span></a><span class="special">(</span><span class="identifier">Engine</span><span class="special">,</span> <span class="identifier">Distribution</span><span class="special">)</span><span class="special">;</span> 46 47 <span class="comment">// <a class="link" href="variate_generator.html#id-1_3_34_5_6_50_1_1_7-bb">public member functions</a></span> 48 <span class="identifier">result_type</span> <a class="link" href="variate_generator.html#id-1_3_34_5_6_50_1_1_7_1-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 49 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> <span class="identifier">result_type</span> <a class="link" href="variate_generator.html#id-1_3_34_5_6_50_1_1_7_2-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">T</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 50 <span class="identifier">engine_value_type</span> <span class="special">&</span> <a class="link" href="variate_generator.html#id-1_3_34_5_6_50_1_1_7_3-bb"><span class="identifier">engine</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 51 <span class="keyword">const</span> <span class="identifier">engine_value_type</span> <span class="special">&</span> <a class="link" href="variate_generator.html#id-1_3_34_5_6_50_1_1_7_4-bb"><span class="identifier">engine</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 52 <span class="identifier">distribution_type</span> <span class="special">&</span> <a class="link" href="variate_generator.html#id-1_3_34_5_6_50_1_1_7_5-bb"><span class="identifier">distribution</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 53 <span class="keyword">const</span> <span class="identifier">distribution_type</span> <span class="special">&</span> <a class="link" href="variate_generator.html#id-1_3_34_5_6_50_1_1_7_6-bb"><span class="identifier">distribution</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 54 <span class="identifier">result_type</span> <a class="link" href="variate_generator.html#id-1_3_34_5_6_50_1_1_7_7-bb"><span class="identifier">min</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 55 <span class="identifier">result_type</span> <a class="link" href="variate_generator.html#id-1_3_34_5_6_50_1_1_7_8-bb"><span class="identifier">max</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 56<span class="special">}</span><span class="special">;</span></pre></div> 57<div class="refsect1"> 58<a name="id-1.3.34.5.6.49.3.4"></a><h2>Description</h2> 59<p>A random variate generator is used to join a random number generator together with a random number distribution. Boost.Random provides a vast choice of <a class="link" href="../boost_random/reference.html#boost_random.reference.generators" title="Generators">generators</a> as well as <a class="link" href="../boost_random/reference.html#boost_random.reference.distributions" title="Distributions">distributions</a> .</p> 60<p>The argument for the template parameter Engine shall be of the form U, U&, or U*, where U models a <a class="link" href="../boost_random/reference.html#boost_random.reference.concepts.uniform_random_number_generator" title="Uniform Random Number Generator">uniform random number generator</a> . Then, the member engine_value_type names U (not the pointer or reference to U).</p> 61<p>Specializations of <code class="computeroutput"><a class="link" href="variate_generator.html" title="Class template variate_generator">variate_generator</a></code> satisfy the requirements of CopyConstructible. They also satisfy the requirements of Assignable unless the template parameter Engine is of the form U&.</p> 62<p>The complexity of all functions specified in this section is constant. No function described in this section except the constructor throws an exception. </p> 63<div class="refsect2"> 64<a name="id-1.3.34.5.6.49.3.4.6"></a><h3> 65<a name="boost.variate_generatorconstruct-copy-destruct"></a><code class="computeroutput">variate_generator</code> 66 public 67 construct/copy/destruct</h3> 68<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"> 69<pre class="literallayout"><a name="id-1_3_34_5_6_50_1_1_8-bb"></a><span class="identifier">variate_generator</span><span class="special">(</span><span class="identifier">Engine</span> e<span class="special">,</span> <span class="identifier">Distribution</span> d<span class="special">)</span><span class="special">;</span></pre> 70<p>Constructs a <code class="computeroutput"><code class="computeroutput"><a class="link" href="variate_generator.html" title="Class template variate_generator">variate_generator</a></code></code> object with the associated <a class="link" href="../boost_random/reference.html#boost_random.reference.concepts.uniform_random_number_generator" title="Uniform Random Number Generator">uniform random number generator</a> eng and the associated <a class="link" href="../boost_random/reference.html#boost_random.reference.concepts.random_distribution" title="Random Distribution">random distribution</a> d.</p> 71<p>Throws: If and what the copy constructor of Engine or Distribution throws. </p> 72</li></ol></div> 73</div> 74<div class="refsect2"> 75<a name="id-1.3.34.5.6.49.3.4.7"></a><h3> 76<a name="id-1_3_34_5_6_50_1_1_7-bb"></a><code class="computeroutput">variate_generator</code> public member functions</h3> 77<div class="orderedlist"><ol class="orderedlist" type="1"> 78<li class="listitem"> 79<pre class="literallayout"><span class="identifier">result_type</span> <a name="id-1_3_34_5_6_50_1_1_7_1-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> 80<p>Returns: distribution()(engine()) </p> 81</li> 82<li class="listitem"> 83<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> <span class="identifier">result_type</span> <a name="id-1_3_34_5_6_50_1_1_7_2-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">T</span> <span class="special">&</span> value<span class="special">)</span><span class="special">;</span></pre> 84<p>Returns: distribution()(engine(), value). </p> 85</li> 86<li class="listitem"> 87<pre class="literallayout"><span class="identifier">engine_value_type</span> <span class="special">&</span> <a name="id-1_3_34_5_6_50_1_1_7_3-bb"></a><span class="identifier">engine</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> 88<p>Returns: A reference to the associated uniform random number generator. </p> 89</li> 90<li class="listitem"> 91<pre class="literallayout"><span class="keyword">const</span> <span class="identifier">engine_value_type</span> <span class="special">&</span> <a name="id-1_3_34_5_6_50_1_1_7_4-bb"></a><span class="identifier">engine</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 92<p>Returns: A reference to the associated uniform random number generator. </p> 93</li> 94<li class="listitem"> 95<pre class="literallayout"><span class="identifier">distribution_type</span> <span class="special">&</span> <a name="id-1_3_34_5_6_50_1_1_7_5-bb"></a><span class="identifier">distribution</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> 96<p>Returns: A reference to the associated <a class="link" href="../boost_random/reference.html#boost_random.reference.concepts.random_distribution" title="Random Distribution">random distribution</a> . </p> 97</li> 98<li class="listitem"> 99<pre class="literallayout"><span class="keyword">const</span> <span class="identifier">distribution_type</span> <span class="special">&</span> <a name="id-1_3_34_5_6_50_1_1_7_6-bb"></a><span class="identifier">distribution</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 100<p>Returns: A reference to the associated random distribution. </p> 101</li> 102<li class="listitem"> 103<pre class="literallayout"><span class="identifier">result_type</span> <a name="id-1_3_34_5_6_50_1_1_7_7-bb"></a><span class="identifier">min</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 104<p>Precondition: distribution().min() is well-formed</p> 105<p>Returns: distribution().min() </p> 106</li> 107<li class="listitem"> 108<pre class="literallayout"><span class="identifier">result_type</span> <a name="id-1_3_34_5_6_50_1_1_7_8-bb"></a><span class="identifier">max</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 109<p>Precondition: distribution().max() is well-formed</p> 110<p>Returns: distribution().max() </p> 111</li> 112</ol></div> 113</div> 114</div> 115</div> 116<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 117<td align="left"></td> 118<td align="right"><div class="copyright-footer">Copyright © 2000-2005 Jens Maurer<br>Copyright © 2009, 2010 Steven Watanabe<p> 119 Distributed under the Boost Software License, Version 1.0. (See accompanying 120 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>) 121 </p> 122</div></td> 123</tr></table> 124<hr> 125<div class="spirit-nav"> 126<a accesskey="p" href="random/uniform_smallint/param_type.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../boost_random/reference.html#header.boost.random.variate_generator_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="random/weibull_distribution.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> 127</div> 128</body> 129</html> 130
