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 poisson_distribution</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.poisson_distribution_hpp" title="Header <boost/random/poisson_distribution.hpp>"> 10<link rel="prev" href="piecew_1_3_34_5_6_32_1_1_1/param_type.html" title="Class param_type"> 11<link rel="next" href="poisson_distribution/param_type.html" title="Class param_type"> 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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src="../../../../doc/src/images/next.png" alt="Next"></a> 25</div> 26<div class="refentry"> 27<a name="boost.random.poisson_distribution"></a><div class="titlepage"></div> 28<div class="refnamediv"> 29<h2><span class="refentrytitle">Class template poisson_distribution</span></h2> 30<p>boost::random::poisson_distribution</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.poisson_distribution_hpp" title="Header <boost/random/poisson_distribution.hpp>">boost/random/poisson_distribution.hpp</a>> 34 35</span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> IntType <span class="special">=</span> <span class="keyword">int</span><span class="special">,</span> <span class="keyword">typename</span> RealType <span class="special">=</span> <span class="keyword">double</span><span class="special">></span> 36<span class="keyword">class</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</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">IntType</span> <a name="boost.random.poisson_distribution.result_type"></a><span class="identifier">result_type</span><span class="special">;</span> 40 <span class="keyword">typedef</span> <span class="identifier">RealType</span> <a name="boost.random.poisson_distribution.input_type"></a><span class="identifier">input_type</span><span class="special">;</span> 41 42 <span class="comment">// member classes/structs/unions</span> 43 44 <span class="keyword">class</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">{</span> 45 <span class="keyword">public</span><span class="special">:</span> 46 <span class="comment">// types</span> 47 <span class="keyword">typedef</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <a class="link" href="poisson_distribution/param_type.html#boost.random.poisson_distribution.param_type.distribution_type"><span class="identifier">distribution_type</span></a><span class="special">;</span> 48 49 <span class="comment">// <a class="link" href="poisson_distribution/param_type.html#boost.random.poisson_distribution.param_typeconstruct-copy-destruct">construct/copy/destruct</a></span> 50 <span class="keyword">explicit</span> <a class="link" href="poisson_distribution/param_type.html#id-1_3_34_5_6_33_1_1_1_3_3-bb"><span class="identifier">param_type</span></a><span class="special">(</span><span class="identifier">RealType</span> <span class="special">=</span> <span class="number">1</span><span class="special">)</span><span class="special">;</span> 51 52 <span class="comment">// <a class="link" href="poisson_distribution/param_type.html#id-1_3_34_5_6_33_1_1_1_3_2-bb">public member functions</a></span> 53 <span class="identifier">RealType</span> <a class="link" href="poisson_distribution/param_type.html#id-1_3_34_5_6_33_1_1_1_3_2_1-bb"><span class="identifier">mean</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 54 55 <span class="comment">// <a class="link" href="poisson_distribution/param_type.html#id-1_3_34_5_6_33_1_1_1_3_4-bb">friend functions</a></span> 56 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> CharT<span class="special">,</span> <span class="keyword">typename</span> Traits<span class="special">></span> 57 <span class="keyword">friend</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span> <span class="identifier">CharT</span><span class="special">,</span> <span class="identifier">Traits</span> <span class="special">></span> <span class="special">&</span> 58 <a class="link" href="poisson_distribution/param_type.html#id-1_3_34_5_6_33_1_1_1_3_4_1-bb"><span class="keyword">operator</span><span class="special"><<</span></a><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span> <span class="identifier">CharT</span><span class="special">,</span> <span class="identifier">Traits</span> <span class="special">></span> <span class="special">&</span><span class="special">,</span> <span class="keyword">const</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 59 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> CharT<span class="special">,</span> <span class="keyword">typename</span> Traits<span class="special">></span> 60 <span class="keyword">friend</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_istream</span><span class="special"><</span> <span class="identifier">CharT</span><span class="special">,</span> <span class="identifier">Traits</span> <span class="special">></span> <span class="special">&</span> 61 <a class="link" href="poisson_distribution/param_type.html#id-1_3_34_5_6_33_1_1_1_3_4_2-bb"><span class="keyword">operator</span><span class="special">>></span></a><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_istream</span><span class="special"><</span> <span class="identifier">CharT</span><span class="special">,</span> <span class="identifier">Traits</span> <span class="special">></span> <span class="special">&</span><span class="special">,</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 62 <span class="keyword">friend</span> <span class="keyword">bool</span> <a class="link" href="poisson_distribution/param_type.html#id-1_3_34_5_6_33_1_1_1_3_4_3-bb"><span class="keyword">operator</span><span class="special">==</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">&</span><span class="special">,</span> <span class="keyword">const</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 63 <span class="keyword">friend</span> <span class="keyword">bool</span> <a class="link" href="poisson_distribution/param_type.html#id-1_3_34_5_6_33_1_1_1_3_4_4-bb"><span class="keyword">operator</span><span class="special">!=</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">&</span><span class="special">,</span> <span class="keyword">const</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 64 <span class="special">}</span><span class="special">;</span> 65 66 <span class="comment">// <a class="link" href="poisson_distribution.html#boost.random.poisson_distributionconstruct-copy-destruct">construct/copy/destruct</a></span> 67 <span class="keyword">explicit</span> <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_7-bb"><span class="identifier">poisson_distribution</span></a><span class="special">(</span><span class="identifier">RealType</span> <span class="special">=</span> <span class="number">1</span><span class="special">)</span><span class="special">;</span> 68 <span class="keyword">explicit</span> <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_8-bb"><span class="identifier">poisson_distribution</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 69 70 <span class="comment">// <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_6-bb">public member functions</a></span> 71 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> URNG<span class="special">></span> <span class="identifier">IntType</span> <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_6_1-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="identifier">URNG</span> <span class="special">&</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 72 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> URNG<span class="special">></span> <span class="identifier">IntType</span> <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_6_2-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="identifier">URNG</span> <span class="special">&</span><span class="special">,</span> <span class="keyword">const</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">&</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 73 <span class="identifier">RealType</span> <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_6_3-bb"><span class="identifier">mean</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 74 <span class="identifier">IntType</span> <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_6_4-bb"><span class="identifier">min</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 75 <span class="identifier">IntType</span> <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_6_5-bb"><span class="identifier">max</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 76 <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_6_6-bb"><span class="identifier">param</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> 77 <span class="keyword">void</span> <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_6_7-bb"><span class="identifier">param</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 78 <span class="keyword">void</span> <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_6_8-bb"><span class="identifier">reset</span></a><span class="special">(</span><span class="special">)</span><span class="special">;</span> 79 80 <span class="comment">// <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_9-bb">friend functions</a></span> 81 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> CharT<span class="special">,</span> <span class="keyword">typename</span> Traits<span class="special">></span> 82 <span class="keyword">friend</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span> <span class="identifier">CharT</span><span class="special">,</span> <span class="identifier">Traits</span> <span class="special">></span> <span class="special">&</span> 83 <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_9_1-bb"><span class="keyword">operator</span><span class="special"><<</span></a><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span> <span class="identifier">CharT</span><span class="special">,</span> <span class="identifier">Traits</span> <span class="special">></span> <span class="special">&</span><span class="special">,</span> 84 <span class="keyword">const</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 85 <span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> CharT<span class="special">,</span> <span class="keyword">typename</span> Traits<span class="special">></span> 86 <span class="keyword">friend</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_istream</span><span class="special"><</span> <span class="identifier">CharT</span><span class="special">,</span> <span class="identifier">Traits</span> <span class="special">></span> <span class="special">&</span> 87 <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_9_2-bb"><span class="keyword">operator</span><span class="special">>></span></a><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_istream</span><span class="special"><</span> <span class="identifier">CharT</span><span class="special">,</span> <span class="identifier">Traits</span> <span class="special">></span> <span class="special">&</span><span class="special">,</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 88 <span class="keyword">friend</span> <span class="keyword">bool</span> <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_9_3-bb"><span class="keyword">operator</span><span class="special">==</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <span class="special">&</span><span class="special">,</span> 89 <span class="keyword">const</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 90 <span class="keyword">friend</span> <span class="keyword">bool</span> <a class="link" href="poisson_distribution.html#id-1_3_34_5_6_33_1_1_1_9_4-bb"><span class="keyword">operator</span><span class="special">!=</span></a><span class="special">(</span><span class="keyword">const</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <span class="special">&</span><span class="special">,</span> 91 <span class="keyword">const</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <span class="special">&</span><span class="special">)</span><span class="special">;</span> 92<span class="special">}</span><span class="special">;</span></pre></div> 93<div class="refsect1"> 94<a name="id-1.3.34.5.6.32.3.4"></a><h2>Description</h2> 95<p>An instantiation of the class template <code class="computeroutput"><a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a></code> is a model of <a class="link" href="../../boost_random/reference.html#boost_random.reference.concepts.random_distribution" title="Random Distribution">random distribution</a> . The poisson distribution has <span class="inlinemediaobject"><img src="../../images/random//form_36.png"></span></p> 96<p>This implementation is based on the PTRD algorithm described</p> 97<p> </p> 98<div class="blockquote"><blockquote class="blockquote"><p> "The transformed rejection method for generating Poisson random variables", Wolfgang Hormann, Insurance: Mathematics and Economics Volume 12, Issue 1, February 1993, Pages 39-45 </p></blockquote></div> 99<p> </p> 100<div class="refsect2"> 101<a name="id-1.3.34.5.6.32.3.4.5"></a><h3> 102<a name="boost.random.poisson_distributionconstruct-copy-destruct"></a><code class="computeroutput">poisson_distribution</code> 103 public 104 construct/copy/destruct</h3> 105<div class="orderedlist"><ol class="orderedlist" type="1"> 106<li class="listitem"> 107<pre class="literallayout"><span class="keyword">explicit</span> <a name="id-1_3_34_5_6_33_1_1_1_7-bb"></a><span class="identifier">poisson_distribution</span><span class="special">(</span><span class="identifier">RealType</span> mean <span class="special">=</span> <span class="number">1</span><span class="special">)</span><span class="special">;</span></pre> 108<p>Constructs a <code class="computeroutput"><code class="computeroutput"><a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a></code></code> with the parameter <code class="computeroutput">mean</code>.</p> 109<p>Requires: mean > 0 </p> 110</li> 111<li class="listitem"> 112<pre class="literallayout"><span class="keyword">explicit</span> <a name="id-1_3_34_5_6_33_1_1_1_8-bb"></a><span class="identifier">poisson_distribution</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">&</span> param<span class="special">)</span><span class="special">;</span></pre> 113<p>Construct an <code class="computeroutput"><code class="computeroutput"><a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a></code></code> object from the parameters. </p> 114</li> 115</ol></div> 116</div> 117<div class="refsect2"> 118<a name="id-1.3.34.5.6.32.3.4.6"></a><h3> 119<a name="id-1_3_34_5_6_33_1_1_1_6-bb"></a><code class="computeroutput">poisson_distribution</code> public member functions</h3> 120<div class="orderedlist"><ol class="orderedlist" type="1"> 121<li class="listitem"> 122<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> URNG<span class="special">></span> <span class="identifier">IntType</span> <a name="id-1_3_34_5_6_33_1_1_1_6_1-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="identifier">URNG</span> <span class="special">&</span> urng<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 123<p>Returns a random variate distributed according to the poisson distribution. </p> 124</li> 125<li class="listitem"> 126<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> URNG<span class="special">></span> 127 <span class="identifier">IntType</span> <a name="id-1_3_34_5_6_33_1_1_1_6_2-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="identifier">URNG</span> <span class="special">&</span> urng<span class="special">,</span> <span class="keyword">const</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">&</span> param<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 128<p>Returns a random variate distributed according to the poisson distribution with parameters specified by param. </p> 129</li> 130<li class="listitem"> 131<pre class="literallayout"><span class="identifier">RealType</span> <a name="id-1_3_34_5_6_33_1_1_1_6_3-bb"></a><span class="identifier">mean</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 132<p>Returns the "mean" parameter of the distribution. </p> 133</li> 134<li class="listitem"> 135<pre class="literallayout"><span class="identifier">IntType</span> <a name="id-1_3_34_5_6_33_1_1_1_6_4-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> 136<p>Returns the smallest value that the distribution can produce. </p> 137</li> 138<li class="listitem"> 139<pre class="literallayout"><span class="identifier">IntType</span> <a name="id-1_3_34_5_6_33_1_1_1_6_5-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> 140<p>Returns the largest value that the distribution can produce. </p> 141</li> 142<li class="listitem"> 143<pre class="literallayout"><a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <a name="id-1_3_34_5_6_33_1_1_1_6_6-bb"></a><span class="identifier">param</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> 144<p>Returns the parameters of the distribution. </p> 145</li> 146<li class="listitem"> 147<pre class="literallayout"><span class="keyword">void</span> <a name="id-1_3_34_5_6_33_1_1_1_6_7-bb"></a><span class="identifier">param</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="poisson_distribution/param_type.html" title="Class param_type">param_type</a> <span class="special">&</span> param<span class="special">)</span><span class="special">;</span></pre> 148<p>Sets parameters of the distribution. </p> 149</li> 150<li class="listitem"> 151<pre class="literallayout"><span class="keyword">void</span> <a name="id-1_3_34_5_6_33_1_1_1_6_8-bb"></a><span class="identifier">reset</span><span class="special">(</span><span class="special">)</span><span class="special">;</span></pre> 152<p>Effects: Subsequent uses of the distribution do not depend on values produced by any engine prior to invoking reset. </p> 153</li> 154</ol></div> 155</div> 156<div class="refsect2"> 157<a name="id-1.3.34.5.6.32.3.4.7"></a><h3> 158<a name="id-1_3_34_5_6_33_1_1_1_9-bb"></a><code class="computeroutput">poisson_distribution</code> friend functions</h3> 159<div class="orderedlist"><ol class="orderedlist" type="1"> 160<li class="listitem"> 161<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> CharT<span class="special">,</span> <span class="keyword">typename</span> Traits<span class="special">></span> 162 <span class="keyword">friend</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span> <span class="identifier">CharT</span><span class="special">,</span> <span class="identifier">Traits</span> <span class="special">></span> <span class="special">&</span> 163 <a name="id-1_3_34_5_6_33_1_1_1_9_1-bb"></a><span class="keyword">operator</span><span class="special"><<</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_ostream</span><span class="special"><</span> <span class="identifier">CharT</span><span class="special">,</span> <span class="identifier">Traits</span> <span class="special">></span> <span class="special">&</span> os<span class="special">,</span> 164 <span class="keyword">const</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <span class="special">&</span> pd<span class="special">)</span><span class="special">;</span></pre> 165<p>Writes the parameters of the distribution to a <code class="computeroutput">std::ostream</code>. </p> 166</li> 167<li class="listitem"> 168<pre class="literallayout"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> CharT<span class="special">,</span> <span class="keyword">typename</span> Traits<span class="special">></span> 169 <span class="keyword">friend</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_istream</span><span class="special"><</span> <span class="identifier">CharT</span><span class="special">,</span> <span class="identifier">Traits</span> <span class="special">></span> <span class="special">&</span> 170 <a name="id-1_3_34_5_6_33_1_1_1_9_2-bb"></a><span class="keyword">operator</span><span class="special">>></span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_istream</span><span class="special"><</span> <span class="identifier">CharT</span><span class="special">,</span> <span class="identifier">Traits</span> <span class="special">></span> <span class="special">&</span> is<span class="special">,</span> 171 <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <span class="special">&</span> pd<span class="special">)</span><span class="special">;</span></pre> 172<p>Reads the parameters of the distribution from a <code class="computeroutput">std::istream</code>. </p> 173</li> 174<li class="listitem"> 175<pre class="literallayout"><span class="keyword">friend</span> <span class="keyword">bool</span> <a name="id-1_3_34_5_6_33_1_1_1_9_3-bb"></a><span class="keyword">operator</span><span class="special">==</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <span class="special">&</span> lhs<span class="special">,</span> 176 <span class="keyword">const</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <span class="special">&</span> rhs<span class="special">)</span><span class="special">;</span></pre> 177<p>Returns true if the two distributions will produce the same sequence of values, given equal generators. </p> 178</li> 179<li class="listitem"> 180<pre class="literallayout"><span class="keyword">friend</span> <span class="keyword">bool</span> <a name="id-1_3_34_5_6_33_1_1_1_9_4-bb"></a><span class="keyword">operator</span><span class="special">!=</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <span class="special">&</span> lhs<span class="special">,</span> 181 <span class="keyword">const</span> <a class="link" href="poisson_distribution.html" title="Class template poisson_distribution">poisson_distribution</a> <span class="special">&</span> rhs<span class="special">)</span><span class="special">;</span></pre> 182<p>Returns true if the two distributions could produce different sequences of values, given equal generators. </p> 183</li> 184</ol></div> 185</div> 186</div> 187</div> 188<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 189<td align="left"></td> 190<td align="right"><div class="copyright-footer">Copyright © 2000-2005 Jens Maurer<br>Copyright © 2009, 2010 Steven Watanabe<p> 191 Distributed under the Boost Software License, Version 1.0. (See accompanying 192 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>) 193 </p> 194</div></td> 195</tr></table> 196<hr> 197<div class="spirit-nav"> 198<a accesskey="p" href="piecew_1_3_34_5_6_32_1_1_1/param_type.html"><img src="../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../../boost_random/reference.html#header.boost.random.poisson_distribution_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="poisson_distribution/param_type.html"><img src="../../../../doc/src/images/next.png" alt="Next"></a> 199</div> 200</body> 201</html> 202
