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+<head><meta http-equiv="content-type" content="text/html; charset=UTF-8" />
+<title>ParetoDistribution xref</title>
+<link type="text/css" rel="stylesheet" href="../../../../../stylesheet.css" />
+</head>
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+<div id="overview"><a href="../../../../../../apidocs/org/apache/commons/statistics/distribution/ParetoDistribution.html">View Javadoc</a></div><pre>
+<a class="jxr_linenumber" name="L1" href="#L1">1</a> <em class="jxr_comment">/*</em>
+<a class="jxr_linenumber" name="L2" href="#L2">2</a> <em class="jxr_comment"> * Licensed to the Apache Software Foundation (ASF) under one or more</em>
+<a class="jxr_linenumber" name="L3" href="#L3">3</a> <em class="jxr_comment"> * contributor license agreements. See the NOTICE file distributed with</em>
+<a class="jxr_linenumber" name="L4" href="#L4">4</a> <em class="jxr_comment"> * this work for additional information regarding copyright ownership.</em>
+<a class="jxr_linenumber" name="L5" href="#L5">5</a> <em class="jxr_comment"> * The ASF licenses this file to You under the Apache License, Version 2.0</em>
+<a class="jxr_linenumber" name="L6" href="#L6">6</a> <em class="jxr_comment"> * (the "License"); you may not use this file except in compliance with</em>
+<a class="jxr_linenumber" name="L7" href="#L7">7</a> <em class="jxr_comment"> * the License. You may obtain a copy of the License at</em>
+<a class="jxr_linenumber" name="L8" href="#L8">8</a> <em class="jxr_comment"> *</em>
+<a class="jxr_linenumber" name="L9" href="#L9">9</a> <em class="jxr_comment"> * <a href="http://www.apache.org/licenses/LICENSE-2.0" target="alexandria_uri">http://www.apache.org/licenses/LICENSE-2.0</a></em>
+<a class="jxr_linenumber" name="L10" href="#L10">10</a> <em class="jxr_comment"> *</em>
+<a class="jxr_linenumber" name="L11" href="#L11">11</a> <em class="jxr_comment"> * Unless required by applicable law or agreed to in writing, software</em>
+<a class="jxr_linenumber" name="L12" href="#L12">12</a> <em class="jxr_comment"> * distributed under the License is distributed on an "AS IS" BASIS,</em>
+<a class="jxr_linenumber" name="L13" href="#L13">13</a> <em class="jxr_comment"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</em>
+<a class="jxr_linenumber" name="L14" href="#L14">14</a> <em class="jxr_comment"> * See the License for the specific language governing permissions and</em>
+<a class="jxr_linenumber" name="L15" href="#L15">15</a> <em class="jxr_comment"> * limitations under the License.</em>
+<a class="jxr_linenumber" name="L16" href="#L16">16</a> <em class="jxr_comment"> */</em>
+<a class="jxr_linenumber" name="L17" href="#L17">17</a>
+<a class="jxr_linenumber" name="L18" href="#L18">18</a> <strong class="jxr_keyword">package</strong> org.apache.commons.statistics.distribution;
+<a class="jxr_linenumber" name="L19" href="#L19">19</a>
+<a class="jxr_linenumber" name="L20" href="#L20">20</a> <strong class="jxr_keyword">import</strong> java.util.function.DoubleUnaryOperator;
+<a class="jxr_linenumber" name="L21" href="#L21">21</a> <strong class="jxr_keyword">import</strong> org.apache.commons.rng.UniformRandomProvider;
+<a class="jxr_linenumber" name="L22" href="#L22">22</a> <strong class="jxr_keyword">import</strong> org.apache.commons.rng.sampling.distribution.InverseTransformParetoSampler;
+<a class="jxr_linenumber" name="L23" href="#L23">23</a>
+<a class="jxr_linenumber" name="L24" href="#L24">24</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L25" href="#L25">25</a> <em class="jxr_javadoccomment"> * Implementation of the Pareto (Type I) distribution.</em>
+<a class="jxr_linenumber" name="L26" href="#L26">26</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L27" href="#L27">27</a> <em class="jxr_javadoccomment"> * <p>The probability density function of \( X \) is:</em>
+<a class="jxr_linenumber" name="L28" href="#L28">28</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L29" href="#L29">29</a> <em class="jxr_javadoccomment"> * <p>\[ f(x; k, \alpha) = \frac{\alpha k^\alpha}{x^{\alpha + 1}} \]</em>
+<a class="jxr_linenumber" name="L30" href="#L30">30</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L31" href="#L31">31</a> <em class="jxr_javadoccomment"> * <p>for \( k &gt; 0 \),</em>
+<a class="jxr_linenumber" name="L32" href="#L32">32</a> <em class="jxr_javadoccomment"> * \( \alpha &gt; 0 \), and</em>
+<a class="jxr_linenumber" name="L33" href="#L33">33</a> <em class="jxr_javadoccomment"> * \( x \in [k, \infty) \).</em>
+<a class="jxr_linenumber" name="L34" href="#L34">34</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L35" href="#L35">35</a> <em class="jxr_javadoccomment"> * <p>\( k \) is a <em>scale</em> parameter: this is the minimum possible value of \( X \).</em>
+<a class="jxr_linenumber" name="L36" href="#L36">36</a> <em class="jxr_javadoccomment"> * <br>\( \alpha \) is a <em>shape</em> parameter: this is the Pareto index.</em>
+<a class="jxr_linenumber" name="L37" href="#L37">37</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L38" href="#L38">38</a> <em class="jxr_javadoccomment"> * @see <a href="<a href="https://en.wikipedia.org/wiki/Pareto_distribution" target="alexandria_uri">https://en.wikipedia.org/wiki/Pareto_distribution</a>">Pareto distribution (Wikipedia)</a></em>
+<a class="jxr_linenumber" name="L39" href="#L39">39</a> <em class="jxr_javadoccomment"> * @see <a href="<a href="https://mathworld.wolfram.com/ParetoDistribution.html" target="alexandria_uri">https://mathworld.wolfram.com/ParetoDistribution.html</a>">Pareto distribution (MathWorld)</a></em>
+<a class="jxr_linenumber" name="L40" href="#L40">40</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L41" href="#L41">41</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">class</strong> <a name="ParetoDistribution" href="../../../../../org/apache/commons/statistics/distribution/ParetoDistribution.html#ParetoDistribution">ParetoDistribution</a> <strong class="jxr_keyword">extends</strong> <a name="AbstractContinuousDistribution" href="../../../../../org/apache/commons/statistics/distribution/AbstractContinuousDistribution.html#AbstractContinuousDistribution">AbstractContinuousDistribution</a> {
+<a class="jxr_linenumber" name="L42" href="#L42">42</a> <em class="jxr_javadoccomment">/** The minimum value for the shape parameter when computing when computing the variance. */</em>
+<a class="jxr_linenumber" name="L43" href="#L43">43</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> MIN_SHAPE_FOR_VARIANCE = 2.0;
+<a class="jxr_linenumber" name="L44" href="#L44">44</a>
+<a class="jxr_linenumber" name="L45" href="#L45">45</a> <em class="jxr_javadoccomment">/** The scale parameter of this distribution. Also known as {@code k};</em>
+<a class="jxr_linenumber" name="L46" href="#L46">46</a> <em class="jxr_javadoccomment"> * the minimum possible value for the random variable {@code X}. */</em>
+<a class="jxr_linenumber" name="L47" href="#L47">47</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> scale;
+<a class="jxr_linenumber" name="L48" href="#L48">48</a> <em class="jxr_javadoccomment">/** The shape parameter of this distribution. */</em>
+<a class="jxr_linenumber" name="L49" href="#L49">49</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> shape;
+<a class="jxr_linenumber" name="L50" href="#L50">50</a> <em class="jxr_javadoccomment">/** Implementation of PDF(x). Assumes that {@code x >= scale}. */</em>
+<a class="jxr_linenumber" name="L51" href="#L51">51</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> DoubleUnaryOperator pdf;
+<a class="jxr_linenumber" name="L52" href="#L52">52</a> <em class="jxr_javadoccomment">/** Implementation of log PDF(x). Assumes that {@code x >= scale}. */</em>
+<a class="jxr_linenumber" name="L53" href="#L53">53</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> DoubleUnaryOperator logpdf;
+<a class="jxr_linenumber" name="L54" href="#L54">54</a>
+<a class="jxr_linenumber" name="L55" href="#L55">55</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L56" href="#L56">56</a> <em class="jxr_javadoccomment"> * @param scale Scale parameter (minimum possible value of X).</em>
+<a class="jxr_linenumber" name="L57" href="#L57">57</a> <em class="jxr_javadoccomment"> * @param shape Shape parameter (Pareto index).</em>
+<a class="jxr_linenumber" name="L58" href="#L58">58</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L59" href="#L59">59</a> <strong class="jxr_keyword">private</strong> <a name="ParetoDistribution" href="../../../../../org/apache/commons/statistics/distribution/ParetoDistribution.html#ParetoDistribution">ParetoDistribution</a>(<strong class="jxr_keyword">double</strong> scale,
+<a class="jxr_linenumber" name="L60" href="#L60">60</a> <strong class="jxr_keyword">double</strong> shape) {
+<a class="jxr_linenumber" name="L61" href="#L61">61</a> <strong class="jxr_keyword">this</strong>.scale = scale;
+<a class="jxr_linenumber" name="L62" href="#L62">62</a> <strong class="jxr_keyword">this</strong>.shape = shape;
+<a class="jxr_linenumber" name="L63" href="#L63">63</a>
+<a class="jxr_linenumber" name="L64" href="#L64">64</a> <em class="jxr_comment">// The Pareto distribution approaches a Dirac delta function when shape -> inf.</em>
+<a class="jxr_linenumber" name="L65" href="#L65">65</a> <em class="jxr_comment">// Parameterisations can also lead to underflow in the standard computation.</em>
+<a class="jxr_linenumber" name="L66" href="#L66">66</a> <em class="jxr_comment">// Extract the PDF and CDF to specialized implementations to handle edge cases.</em>
+<a class="jxr_linenumber" name="L67" href="#L67">67</a>
+<a class="jxr_linenumber" name="L68" href="#L68">68</a> <em class="jxr_comment">// Pre-compute factors for the standard computation</em>
+<a class="jxr_linenumber" name="L69" href="#L69">69</a> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> shapeByScalePowShape = shape * Math.pow(scale, shape);
+<a class="jxr_linenumber" name="L70" href="#L70">70</a> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> logShapePlusShapeByLogScale = Math.log(shape) + Math.log(scale) * shape;
+<a class="jxr_linenumber" name="L71" href="#L71">71</a>
+<a class="jxr_linenumber" name="L72" href="#L72">72</a> <strong class="jxr_keyword">if</strong> (shapeByScalePowShape < Double.POSITIVE_INFINITY &&
+<a class="jxr_linenumber" name="L73" href="#L73">73</a> shapeByScalePowShape >= Double.MIN_NORMAL) {
+<a class="jxr_linenumber" name="L74" href="#L74">74</a> <em class="jxr_comment">// Standard computation</em>
+<a class="jxr_linenumber" name="L75" href="#L75">75</a> pdf = x -> shapeByScalePowShape / Math.pow(x, shape + 1);
+<a class="jxr_linenumber" name="L76" href="#L76">76</a> logpdf = x -> logShapePlusShapeByLogScale - Math.log(x) * (shape + 1);
+<a class="jxr_linenumber" name="L77" href="#L77">77</a> } <strong class="jxr_keyword">else</strong> {
+<a class="jxr_linenumber" name="L78" href="#L78">78</a> <em class="jxr_comment">// Standard computation overflow; underflow to sub-normal or zero; or nan (pow(1.0, inf))</em>
+<a class="jxr_linenumber" name="L79" href="#L79">79</a> <strong class="jxr_keyword">if</strong> (Double.isFinite(logShapePlusShapeByLogScale)) {
+<a class="jxr_linenumber" name="L80" href="#L80">80</a> <em class="jxr_comment">// Log computation is valid</em>
+<a class="jxr_linenumber" name="L81" href="#L81">81</a> logpdf = x -> logShapePlusShapeByLogScale - Math.log(x) * (shape + 1);
+<a class="jxr_linenumber" name="L82" href="#L82">82</a> pdf = x -> Math.exp(logpdf.applyAsDouble(x));
+<a class="jxr_linenumber" name="L83" href="#L83">83</a> } <strong class="jxr_keyword">else</strong> {
+<a class="jxr_linenumber" name="L84" href="#L84">84</a> <em class="jxr_comment">// Assume Dirac function</em>
+<a class="jxr_linenumber" name="L85" href="#L85">85</a> logpdf = x -> x > scale ? Double.NEGATIVE_INFINITY : Double.POSITIVE_INFINITY;
+<a class="jxr_linenumber" name="L86" href="#L86">86</a> <em class="jxr_comment">// PDF has infinite value at lower bound</em>
+<a class="jxr_linenumber" name="L87" href="#L87">87</a> pdf = x -> x > scale ? 0 : Double.POSITIVE_INFINITY;
+<a class="jxr_linenumber" name="L88" href="#L88">88</a> }
+<a class="jxr_linenumber" name="L89" href="#L89">89</a> }
+<a class="jxr_linenumber" name="L90" href="#L90">90</a> }
+<a class="jxr_linenumber" name="L91" href="#L91">91</a>
+<a class="jxr_linenumber" name="L92" href="#L92">92</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L93" href="#L93">93</a> <em class="jxr_javadoccomment"> * Creates a Pareto distribution.</em>
+<a class="jxr_linenumber" name="L94" href="#L94">94</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L95" href="#L95">95</a> <em class="jxr_javadoccomment"> * @param scale Scale parameter (minimum possible value of X).</em>
+<a class="jxr_linenumber" name="L96" href="#L96">96</a> <em class="jxr_javadoccomment"> * @param shape Shape parameter (Pareto index).</em>
+<a class="jxr_linenumber" name="L97" href="#L97">97</a> <em class="jxr_javadoccomment"> * @return the distribution</em>
+<a class="jxr_linenumber" name="L98" href="#L98">98</a> <em class="jxr_javadoccomment"> * @throws IllegalArgumentException if {@code scale <= 0}, {@code scale} is</em>
+<a class="jxr_linenumber" name="L99" href="#L99">99</a> <em class="jxr_javadoccomment"> * infinite, or {@code shape <= 0}.</em>
+<a class="jxr_linenumber" name="L100" href="#L100">100</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L101" href="#L101">101</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <a name="ParetoDistribution" href="../../../../../org/apache/commons/statistics/distribution/ParetoDistribution.html#ParetoDistribution">ParetoDistribution</a> of(<strong class="jxr_keyword">double</strong> scale,
+<a class="jxr_linenumber" name="L102" href="#L102">102</a> <strong class="jxr_keyword">double</strong> shape) {
+<a class="jxr_linenumber" name="L103" href="#L103">103</a> <strong class="jxr_keyword">if</strong> (scale <= 0 || scale == Double.POSITIVE_INFINITY) {
+<a class="jxr_linenumber" name="L104" href="#L104">104</a> <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> <a name="DistributionException" href="../../../../../org/apache/commons/statistics/distribution/DistributionException.html#DistributionException">DistributionException</a>(DistributionException.NOT_STRICTLY_POSITIVE_FINITE, scale);
+<a class="jxr_linenumber" name="L105" href="#L105">105</a> }
+<a class="jxr_linenumber" name="L106" href="#L106">106</a> <strong class="jxr_keyword">if</strong> (shape <= 0) {
+<a class="jxr_linenumber" name="L107" href="#L107">107</a> <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> <a name="DistributionException" href="../../../../../org/apache/commons/statistics/distribution/DistributionException.html#DistributionException">DistributionException</a>(DistributionException.NOT_STRICTLY_POSITIVE, shape);
+<a class="jxr_linenumber" name="L108" href="#L108">108</a> }
+<a class="jxr_linenumber" name="L109" href="#L109">109</a> <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">new</strong> <a name="ParetoDistribution" href="../../../../../org/apache/commons/statistics/distribution/ParetoDistribution.html#ParetoDistribution">ParetoDistribution</a>(scale, shape);
+<a class="jxr_linenumber" name="L110" href="#L110">110</a> }
+<a class="jxr_linenumber" name="L111" href="#L111">111</a>
+<a class="jxr_linenumber" name="L112" href="#L112">112</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L113" href="#L113">113</a> <em class="jxr_javadoccomment"> * Gets the scale parameter of this distribution.</em>
+<a class="jxr_linenumber" name="L114" href="#L114">114</a> <em class="jxr_javadoccomment"> * This is the minimum possible value of X.</em>
+<a class="jxr_linenumber" name="L115" href="#L115">115</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L116" href="#L116">116</a> <em class="jxr_javadoccomment"> * @return the scale parameter.</em>
+<a class="jxr_linenumber" name="L117" href="#L117">117</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L118" href="#L118">118</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> getScale() {
+<a class="jxr_linenumber" name="L119" href="#L119">119</a> <strong class="jxr_keyword">return</strong> scale;
+<a class="jxr_linenumber" name="L120" href="#L120">120</a> }
+<a class="jxr_linenumber" name="L121" href="#L121">121</a>
+<a class="jxr_linenumber" name="L122" href="#L122">122</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L123" href="#L123">123</a> <em class="jxr_javadoccomment"> * Gets the shape parameter of this distribution.</em>
+<a class="jxr_linenumber" name="L124" href="#L124">124</a> <em class="jxr_javadoccomment"> * This is the Pareto index.</em>
+<a class="jxr_linenumber" name="L125" href="#L125">125</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L126" href="#L126">126</a> <em class="jxr_javadoccomment"> * @return the shape parameter.</em>
+<a class="jxr_linenumber" name="L127" href="#L127">127</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L128" href="#L128">128</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> getShape() {
+<a class="jxr_linenumber" name="L129" href="#L129">129</a> <strong class="jxr_keyword">return</strong> shape;
+<a class="jxr_linenumber" name="L130" href="#L130">130</a> }
+<a class="jxr_linenumber" name="L131" href="#L131">131</a>
+<a class="jxr_linenumber" name="L132" href="#L132">132</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L133" href="#L133">133</a> <em class="jxr_javadoccomment"> * {@inheritDoc}</em>
+<a class="jxr_linenumber" name="L134" href="#L134">134</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L135" href="#L135">135</a> <em class="jxr_javadoccomment"> * <p>For scale parameter \( k \) and shape parameter \( \alpha \), the PDF is:</em>
+<a class="jxr_linenumber" name="L136" href="#L136">136</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L137" href="#L137">137</a> <em class="jxr_javadoccomment"> * <p>\[ f(x; k, \alpha) = \begin{cases}</em>
+<a class="jxr_linenumber" name="L138" href="#L138">138</a> <em class="jxr_javadoccomment"> * 0 &amp; \text{for } x \lt k \\</em>
+<a class="jxr_linenumber" name="L139" href="#L139">139</a> <em class="jxr_javadoccomment"> * \frac{\alpha k^\alpha}{x^{\alpha + 1}} &amp; \text{for } x \ge k</em>
+<a class="jxr_linenumber" name="L140" href="#L140">140</a> <em class="jxr_javadoccomment"> * \end{cases} \]</em>
+<a class="jxr_linenumber" name="L141" href="#L141">141</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L142" href="#L142">142</a> @Override
+<a class="jxr_linenumber" name="L143" href="#L143">143</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> density(<strong class="jxr_keyword">double</strong> x) {
+<a class="jxr_linenumber" name="L144" href="#L144">144</a> <strong class="jxr_keyword">if</strong> (x < scale) {
+<a class="jxr_linenumber" name="L145" href="#L145">145</a> <strong class="jxr_keyword">return</strong> 0;
+<a class="jxr_linenumber" name="L146" href="#L146">146</a> }
+<a class="jxr_linenumber" name="L147" href="#L147">147</a> <strong class="jxr_keyword">return</strong> pdf.applyAsDouble(x);
+<a class="jxr_linenumber" name="L148" href="#L148">148</a> }
+<a class="jxr_linenumber" name="L149" href="#L149">149</a>
+<a class="jxr_linenumber" name="L150" href="#L150">150</a> <em class="jxr_javadoccomment">/** {@inheritDoc}</em>
+<a class="jxr_linenumber" name="L151" href="#L151">151</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L152" href="#L152">152</a> <em class="jxr_javadoccomment"> * <p>See documentation of {@link #density(double)} for computation details.</em>
+<a class="jxr_linenumber" name="L153" href="#L153">153</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L154" href="#L154">154</a> @Override
+<a class="jxr_linenumber" name="L155" href="#L155">155</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> logDensity(<strong class="jxr_keyword">double</strong> x) {
+<a class="jxr_linenumber" name="L156" href="#L156">156</a> <strong class="jxr_keyword">if</strong> (x < scale) {
+<a class="jxr_linenumber" name="L157" href="#L157">157</a> <strong class="jxr_keyword">return</strong> Double.NEGATIVE_INFINITY;
+<a class="jxr_linenumber" name="L158" href="#L158">158</a> }
+<a class="jxr_linenumber" name="L159" href="#L159">159</a> <strong class="jxr_keyword">return</strong> logpdf.applyAsDouble(x);
+<a class="jxr_linenumber" name="L160" href="#L160">160</a> }
+<a class="jxr_linenumber" name="L161" href="#L161">161</a>
+<a class="jxr_linenumber" name="L162" href="#L162">162</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L163" href="#L163">163</a> <em class="jxr_javadoccomment"> * {@inheritDoc}</em>
+<a class="jxr_linenumber" name="L164" href="#L164">164</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L165" href="#L165">165</a> <em class="jxr_javadoccomment"> * <p>For scale parameter \( k \) and shape parameter \( \alpha \), the CDF is:</em>
+<a class="jxr_linenumber" name="L166" href="#L166">166</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L167" href="#L167">167</a> <em class="jxr_javadoccomment"> * <p>\[ F(x; k, \alpha) = \begin{cases}</em>
+<a class="jxr_linenumber" name="L168" href="#L168">168</a> <em class="jxr_javadoccomment"> * 0 &amp; \text{for } x \le k \\</em>
+<a class="jxr_linenumber" name="L169" href="#L169">169</a> <em class="jxr_javadoccomment"> * 1 - \left( \frac{k}{x} \right)^\alpha &amp; \text{for } x \gt k</em>
+<a class="jxr_linenumber" name="L170" href="#L170">170</a> <em class="jxr_javadoccomment"> * \end{cases} \]</em>
+<a class="jxr_linenumber" name="L171" href="#L171">171</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L172" href="#L172">172</a> @Override
+<a class="jxr_linenumber" name="L173" href="#L173">173</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> cumulativeProbability(<strong class="jxr_keyword">double</strong> x) {
+<a class="jxr_linenumber" name="L174" href="#L174">174</a> <strong class="jxr_keyword">if</strong> (x <= scale) {
+<a class="jxr_linenumber" name="L175" href="#L175">175</a> <strong class="jxr_keyword">return</strong> 0;
+<a class="jxr_linenumber" name="L176" href="#L176">176</a> }
+<a class="jxr_linenumber" name="L177" href="#L177">177</a> <em class="jxr_comment">// Increase accuracy for CDF close to 0 by using a log calculation:</em>
+<a class="jxr_linenumber" name="L178" href="#L178">178</a> <em class="jxr_comment">// 1 - exp(α * ln(k / x)) == -(exp(α * ln(k / x)) - 1)</em>
+<a class="jxr_linenumber" name="L179" href="#L179">179</a> <strong class="jxr_keyword">return</strong> -Math.expm1(shape * Math.log(scale / x));
+<a class="jxr_linenumber" name="L180" href="#L180">180</a> }
+<a class="jxr_linenumber" name="L181" href="#L181">181</a>
+<a class="jxr_linenumber" name="L182" href="#L182">182</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L183" href="#L183">183</a> <em class="jxr_javadoccomment"> * {@inheritDoc}</em>
+<a class="jxr_linenumber" name="L184" href="#L184">184</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L185" href="#L185">185</a> <em class="jxr_javadoccomment"> * <p>For scale parameter \( k \) and shape parameter \( \alpha \), the survival function is:</em>
+<a class="jxr_linenumber" name="L186" href="#L186">186</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L187" href="#L187">187</a> <em class="jxr_javadoccomment"> * <p>\[ S(x; k, \alpha) = \begin{cases}</em>
+<a class="jxr_linenumber" name="L188" href="#L188">188</a> <em class="jxr_javadoccomment"> * 1 &amp; \text{for } x \le k \\</em>
+<a class="jxr_linenumber" name="L189" href="#L189">189</a> <em class="jxr_javadoccomment"> * \left( \frac{k}{x} \right)^\alpha &amp; \text{for } x \gt k</em>
+<a class="jxr_linenumber" name="L190" href="#L190">190</a> <em class="jxr_javadoccomment"> * \end{cases} \]</em>
+<a class="jxr_linenumber" name="L191" href="#L191">191</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L192" href="#L192">192</a> @Override
+<a class="jxr_linenumber" name="L193" href="#L193">193</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> survivalProbability(<strong class="jxr_keyword">double</strong> x) {
+<a class="jxr_linenumber" name="L194" href="#L194">194</a> <strong class="jxr_keyword">if</strong> (x <= scale) {
+<a class="jxr_linenumber" name="L195" href="#L195">195</a> <strong class="jxr_keyword">return</strong> 1;
+<a class="jxr_linenumber" name="L196" href="#L196">196</a> }
+<a class="jxr_linenumber" name="L197" href="#L197">197</a> <strong class="jxr_keyword">return</strong> Math.pow(scale / x, shape);
+<a class="jxr_linenumber" name="L198" href="#L198">198</a> }
+<a class="jxr_linenumber" name="L199" href="#L199">199</a>
+<a class="jxr_linenumber" name="L200" href="#L200">200</a> <em class="jxr_javadoccomment">/** {@inheritDoc} */</em>
+<a class="jxr_linenumber" name="L201" href="#L201">201</a> @Override
+<a class="jxr_linenumber" name="L202" href="#L202">202</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> inverseCumulativeProbability(<strong class="jxr_keyword">double</strong> p) {
+<a class="jxr_linenumber" name="L203" href="#L203">203</a> ArgumentUtils.checkProbability(p);
+<a class="jxr_linenumber" name="L204" href="#L204">204</a> <strong class="jxr_keyword">if</strong> (p == 0) {
+<a class="jxr_linenumber" name="L205" href="#L205">205</a> <strong class="jxr_keyword">return</strong> getSupportLowerBound();
+<a class="jxr_linenumber" name="L206" href="#L206">206</a> }
+<a class="jxr_linenumber" name="L207" href="#L207">207</a> <strong class="jxr_keyword">if</strong> (p == 1) {
+<a class="jxr_linenumber" name="L208" href="#L208">208</a> <strong class="jxr_keyword">return</strong> getSupportUpperBound();
+<a class="jxr_linenumber" name="L209" href="#L209">209</a> }
+<a class="jxr_linenumber" name="L210" href="#L210">210</a> <strong class="jxr_keyword">return</strong> scale / Math.exp(Math.log1p(-p) / shape);
+<a class="jxr_linenumber" name="L211" href="#L211">211</a> }
+<a class="jxr_linenumber" name="L212" href="#L212">212</a>
+<a class="jxr_linenumber" name="L213" href="#L213">213</a> <em class="jxr_javadoccomment">/** {@inheritDoc} */</em>
+<a class="jxr_linenumber" name="L214" href="#L214">214</a> @Override
+<a class="jxr_linenumber" name="L215" href="#L215">215</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> inverseSurvivalProbability(<strong class="jxr_keyword">double</strong> p) {
+<a class="jxr_linenumber" name="L216" href="#L216">216</a> ArgumentUtils.checkProbability(p);
+<a class="jxr_linenumber" name="L217" href="#L217">217</a> <strong class="jxr_keyword">if</strong> (p == 1) {
+<a class="jxr_linenumber" name="L218" href="#L218">218</a> <strong class="jxr_keyword">return</strong> getSupportLowerBound();
+<a class="jxr_linenumber" name="L219" href="#L219">219</a> }
+<a class="jxr_linenumber" name="L220" href="#L220">220</a> <strong class="jxr_keyword">if</strong> (p == 0) {
+<a class="jxr_linenumber" name="L221" href="#L221">221</a> <strong class="jxr_keyword">return</strong> getSupportUpperBound();
+<a class="jxr_linenumber" name="L222" href="#L222">222</a> }
+<a class="jxr_linenumber" name="L223" href="#L223">223</a> <strong class="jxr_keyword">return</strong> scale / Math.pow(p, 1 / shape);
+<a class="jxr_linenumber" name="L224" href="#L224">224</a> }
+<a class="jxr_linenumber" name="L225" href="#L225">225</a>
+<a class="jxr_linenumber" name="L226" href="#L226">226</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L227" href="#L227">227</a> <em class="jxr_javadoccomment"> * {@inheritDoc}</em>
+<a class="jxr_linenumber" name="L228" href="#L228">228</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L229" href="#L229">229</a> <em class="jxr_javadoccomment"> * <p>For scale parameter \( k \) and shape parameter \( \alpha \), the mean is:</em>
+<a class="jxr_linenumber" name="L230" href="#L230">230</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L231" href="#L231">231</a> <em class="jxr_javadoccomment"> * <p>\[ \mathbb{E}[X] = \begin{cases}</em>
+<a class="jxr_linenumber" name="L232" href="#L232">232</a> <em class="jxr_javadoccomment"> * \infty &amp; \text{for } \alpha \le 1 \\</em>
+<a class="jxr_linenumber" name="L233" href="#L233">233</a> <em class="jxr_javadoccomment"> * \frac{k \alpha}{(\alpha-1)} &amp; \text{for } \alpha \gt 1</em>
+<a class="jxr_linenumber" name="L234" href="#L234">234</a> <em class="jxr_javadoccomment"> * \end{cases} \]</em>
+<a class="jxr_linenumber" name="L235" href="#L235">235</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L236" href="#L236">236</a> @Override
+<a class="jxr_linenumber" name="L237" href="#L237">237</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> getMean() {
+<a class="jxr_linenumber" name="L238" href="#L238">238</a> <strong class="jxr_keyword">if</strong> (shape <= 1) {
+<a class="jxr_linenumber" name="L239" href="#L239">239</a> <strong class="jxr_keyword">return</strong> Double.POSITIVE_INFINITY;
+<a class="jxr_linenumber" name="L240" href="#L240">240</a> }
+<a class="jxr_linenumber" name="L241" href="#L241">241</a> <strong class="jxr_keyword">if</strong> (shape == Double.POSITIVE_INFINITY) {
+<a class="jxr_linenumber" name="L242" href="#L242">242</a> <strong class="jxr_keyword">return</strong> scale;
+<a class="jxr_linenumber" name="L243" href="#L243">243</a> }
+<a class="jxr_linenumber" name="L244" href="#L244">244</a> <strong class="jxr_keyword">return</strong> scale * (shape / (shape - 1));
+<a class="jxr_linenumber" name="L245" href="#L245">245</a> }
+<a class="jxr_linenumber" name="L246" href="#L246">246</a>
+<a class="jxr_linenumber" name="L247" href="#L247">247</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L248" href="#L248">248</a> <em class="jxr_javadoccomment"> * {@inheritDoc}</em>
+<a class="jxr_linenumber" name="L249" href="#L249">249</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L250" href="#L250">250</a> <em class="jxr_javadoccomment"> * <p>For scale parameter \( k \) and shape parameter \( \alpha \), the variance is:</em>
+<a class="jxr_linenumber" name="L251" href="#L251">251</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L252" href="#L252">252</a> <em class="jxr_javadoccomment"> * <p>\[ \operatorname{var}[X] = \begin{cases}</em>
+<a class="jxr_linenumber" name="L253" href="#L253">253</a> <em class="jxr_javadoccomment"> * \infty &amp; \text{for } \alpha \le 2 \\</em>
+<a class="jxr_linenumber" name="L254" href="#L254">254</a> <em class="jxr_javadoccomment"> * \frac{k^2 \alpha}{(\alpha-1)^2 (\alpha-2)} &amp; \text{for } \alpha \gt 2</em>
+<a class="jxr_linenumber" name="L255" href="#L255">255</a> <em class="jxr_javadoccomment"> * \end{cases} \]</em>
+<a class="jxr_linenumber" name="L256" href="#L256">256</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L257" href="#L257">257</a> @Override
+<a class="jxr_linenumber" name="L258" href="#L258">258</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> getVariance() {
+<a class="jxr_linenumber" name="L259" href="#L259">259</a> <strong class="jxr_keyword">if</strong> (shape <= MIN_SHAPE_FOR_VARIANCE) {
+<a class="jxr_linenumber" name="L260" href="#L260">260</a> <strong class="jxr_keyword">return</strong> Double.POSITIVE_INFINITY;
+<a class="jxr_linenumber" name="L261" href="#L261">261</a> }
+<a class="jxr_linenumber" name="L262" href="#L262">262</a> <strong class="jxr_keyword">if</strong> (shape == Double.POSITIVE_INFINITY) {
+<a class="jxr_linenumber" name="L263" href="#L263">263</a> <strong class="jxr_keyword">return</strong> 0;
+<a class="jxr_linenumber" name="L264" href="#L264">264</a> }
+<a class="jxr_linenumber" name="L265" href="#L265">265</a> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> s = shape - 1;
+<a class="jxr_linenumber" name="L266" href="#L266">266</a> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> z = shape / s / s / (shape - 2);
+<a class="jxr_linenumber" name="L267" href="#L267">267</a> <em class="jxr_comment">// Avoid intermediate overflow of scale^2 if z is small</em>
+<a class="jxr_linenumber" name="L268" href="#L268">268</a> <strong class="jxr_keyword">return</strong> z < 1 ? z * scale * scale : scale * scale * z;
+<a class="jxr_linenumber" name="L269" href="#L269">269</a> }
+<a class="jxr_linenumber" name="L270" href="#L270">270</a>
+<a class="jxr_linenumber" name="L271" href="#L271">271</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L272" href="#L272">272</a> <em class="jxr_javadoccomment"> * {@inheritDoc}</em>
+<a class="jxr_linenumber" name="L273" href="#L273">273</a> <em class="jxr_javadoccomment"> * <p></em>
+<a class="jxr_linenumber" name="L274" href="#L274">274</a> <em class="jxr_javadoccomment"> * The lower bound of the support is equal to the scale parameter {@code k}.</em>
+<a class="jxr_linenumber" name="L275" href="#L275">275</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L276" href="#L276">276</a> <em class="jxr_javadoccomment"> * @return scale.</em>
+<a class="jxr_linenumber" name="L277" href="#L277">277</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L278" href="#L278">278</a> @Override
+<a class="jxr_linenumber" name="L279" href="#L279">279</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> getSupportLowerBound() {
+<a class="jxr_linenumber" name="L280" href="#L280">280</a> <strong class="jxr_keyword">return</strong> getScale();
+<a class="jxr_linenumber" name="L281" href="#L281">281</a> }
+<a class="jxr_linenumber" name="L282" href="#L282">282</a>
+<a class="jxr_linenumber" name="L283" href="#L283">283</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L284" href="#L284">284</a> <em class="jxr_javadoccomment"> * {@inheritDoc}</em>
+<a class="jxr_linenumber" name="L285" href="#L285">285</a> <em class="jxr_javadoccomment"> * <p></em>
+<a class="jxr_linenumber" name="L286" href="#L286">286</a> <em class="jxr_javadoccomment"> * The upper bound of the support is always positive infinity.</em>
+<a class="jxr_linenumber" name="L287" href="#L287">287</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L288" href="#L288">288</a> <em class="jxr_javadoccomment"> * @return {@link Double#POSITIVE_INFINITY positive infinity}.</em>
+<a class="jxr_linenumber" name="L289" href="#L289">289</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L290" href="#L290">290</a> @Override
+<a class="jxr_linenumber" name="L291" href="#L291">291</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> getSupportUpperBound() {
+<a class="jxr_linenumber" name="L292" href="#L292">292</a> <strong class="jxr_keyword">return</strong> Double.POSITIVE_INFINITY;
+<a class="jxr_linenumber" name="L293" href="#L293">293</a> }
+<a class="jxr_linenumber" name="L294" href="#L294">294</a>
+<a class="jxr_linenumber" name="L295" href="#L295">295</a> <em class="jxr_javadoccomment">/** {@inheritDoc} */</em>
+<a class="jxr_linenumber" name="L296" href="#L296">296</a> @Override
+<a class="jxr_linenumber" name="L297" href="#L297">297</a> <strong class="jxr_keyword">public</strong> ContinuousDistribution.Sampler createSampler(<strong class="jxr_keyword">final</strong> UniformRandomProvider rng) {
+<a class="jxr_linenumber" name="L298" href="#L298">298</a> <em class="jxr_comment">// Pareto distribution sampler.</em>
+<a class="jxr_linenumber" name="L299" href="#L299">299</a> <em class="jxr_comment">// Commons RNG v1.5 uses nextDouble for (1 - p) effectively sampling from p in (0, 1].</em>
+<a class="jxr_linenumber" name="L300" href="#L300">300</a> <em class="jxr_comment">// Ensure sampling is concentrated at the lower / upper bound at extreme shapes:</em>
+<a class="jxr_linenumber" name="L301" href="#L301">301</a> <em class="jxr_comment">// Large shape should sample using p in [0, 1) (lower bound)</em>
+<a class="jxr_linenumber" name="L302" href="#L302">302</a> <em class="jxr_comment">// Small shape should sample using p in (0, 1] (upper bound)</em>
+<a class="jxr_linenumber" name="L303" href="#L303">303</a> <em class="jxr_comment">// Note: For small shape the input RNG is also wrapped to use nextLong as the source of</em>
+<a class="jxr_linenumber" name="L304" href="#L304">304</a> <em class="jxr_comment">// randomness; this ensures the nextDouble method uses the interface output of [0, 1).</em>
+<a class="jxr_linenumber" name="L305" href="#L305">305</a> <em class="jxr_comment">// Commons RNG v1.6 uses nextLong and will not be affected by changes to nextDouble.</em>
+<a class="jxr_linenumber" name="L306" href="#L306">306</a> <strong class="jxr_keyword">final</strong> UniformRandomProvider wrappedRng = shape >= 1 ? <strong class="jxr_keyword">new</strong> InvertedRNG(rng) : rng::nextLong;
+<a class="jxr_linenumber" name="L307" href="#L307">307</a> <strong class="jxr_keyword">return</strong> InverseTransformParetoSampler.of(wrappedRng, scale, shape)::sample;
+<a class="jxr_linenumber" name="L308" href="#L308">308</a> }
+<a class="jxr_linenumber" name="L309" href="#L309">309</a>
+<a class="jxr_linenumber" name="L310" href="#L310">310</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L311" href="#L311">311</a> <em class="jxr_javadoccomment"> * Create a RNG that inverts the output from nextDouble() as (1 - nextDouble()).</em>
+<a class="jxr_linenumber" name="L312" href="#L312">312</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L313" href="#L313">313</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">class</strong> InvertedRNG <strong class="jxr_keyword">implements</strong> UniformRandomProvider {
+<a class="jxr_linenumber" name="L314" href="#L314">314</a> <em class="jxr_javadoccomment">/** Source of randomness. */</em>
+<a class="jxr_linenumber" name="L315" href="#L315">315</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> UniformRandomProvider rng;
+<a class="jxr_linenumber" name="L316" href="#L316">316</a>
+<a class="jxr_linenumber" name="L317" href="#L317">317</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L318" href="#L318">318</a> <em class="jxr_javadoccomment"> * @param rng Source of randomness</em>
+<a class="jxr_linenumber" name="L319" href="#L319">319</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L320" href="#L320">320</a> InvertedRNG(UniformRandomProvider rng) {
+<a class="jxr_linenumber" name="L321" href="#L321">321</a> <strong class="jxr_keyword">this</strong>.rng = rng;
+<a class="jxr_linenumber" name="L322" href="#L322">322</a> }
+<a class="jxr_linenumber" name="L323" href="#L323">323</a>
+<a class="jxr_linenumber" name="L324" href="#L324">324</a> @Override
+<a class="jxr_linenumber" name="L325" href="#L325">325</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">long</strong> nextLong() {
+<a class="jxr_linenumber" name="L326" href="#L326">326</a> <em class="jxr_comment">// Delegate the source of randomness</em>
+<a class="jxr_linenumber" name="L327" href="#L327">327</a> <strong class="jxr_keyword">return</strong> rng.nextLong();
+<a class="jxr_linenumber" name="L328" href="#L328">328</a> }
+<a class="jxr_linenumber" name="L329" href="#L329">329</a>
+<a class="jxr_linenumber" name="L330" href="#L330">330</a> @Override
+<a class="jxr_linenumber" name="L331" href="#L331">331</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> nextDouble() {
+<a class="jxr_linenumber" name="L332" href="#L332">332</a> <em class="jxr_comment">// Return a value in (0, 1].</em>
+<a class="jxr_linenumber" name="L333" href="#L333">333</a> <em class="jxr_comment">// This assumes the interface method outputs in [0, 1).</em>
+<a class="jxr_linenumber" name="L334" href="#L334">334</a> <strong class="jxr_keyword">return</strong> 1 - UniformRandomProvider.<strong class="jxr_keyword">super</strong>.nextDouble();
+<a class="jxr_linenumber" name="L335" href="#L335">335</a> }
+<a class="jxr_linenumber" name="L336" href="#L336">336</a> }
+<a class="jxr_linenumber" name="L337" href="#L337">337</a> }
+</pre>
+<hr/>
+<div id="footer">Copyright © 2018–2022 <a href="https://www.apache.org/">The Apache Software Foundation</a>. All rights reserved.</div>
+</body>
+</html>
Added: dev/commons/statistics/1.0-RC1/site/xref/org/apache/commons/statistics/distribution/PascalDistribution.html
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+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+<head><meta http-equiv="content-type" content="text/html; charset=UTF-8" />
+<title>PascalDistribution xref</title>
+<link type="text/css" rel="stylesheet" href="../../../../../stylesheet.css" />
+</head>
+<body>
+<div id="overview"><a href="../../../../../../apidocs/org/apache/commons/statistics/distribution/PascalDistribution.html">View Javadoc</a></div><pre>
+<a class="jxr_linenumber" name="L1" href="#L1">1</a> <em class="jxr_comment">/*</em>
+<a class="jxr_linenumber" name="L2" href="#L2">2</a> <em class="jxr_comment"> * Licensed to the Apache Software Foundation (ASF) under one or more</em>
+<a class="jxr_linenumber" name="L3" href="#L3">3</a> <em class="jxr_comment"> * contributor license agreements. See the NOTICE file distributed with</em>
+<a class="jxr_linenumber" name="L4" href="#L4">4</a> <em class="jxr_comment"> * this work for additional information regarding copyright ownership.</em>
+<a class="jxr_linenumber" name="L5" href="#L5">5</a> <em class="jxr_comment"> * The ASF licenses this file to You under the Apache License, Version 2.0</em>
+<a class="jxr_linenumber" name="L6" href="#L6">6</a> <em class="jxr_comment"> * (the "License"); you may not use this file except in compliance with</em>
+<a class="jxr_linenumber" name="L7" href="#L7">7</a> <em class="jxr_comment"> * the License. You may obtain a copy of the License at</em>
+<a class="jxr_linenumber" name="L8" href="#L8">8</a> <em class="jxr_comment"> *</em>
+<a class="jxr_linenumber" name="L9" href="#L9">9</a> <em class="jxr_comment"> * <a href="http://www.apache.org/licenses/LICENSE-2.0" target="alexandria_uri">http://www.apache.org/licenses/LICENSE-2.0</a></em>
+<a class="jxr_linenumber" name="L10" href="#L10">10</a> <em class="jxr_comment"> *</em>
+<a class="jxr_linenumber" name="L11" href="#L11">11</a> <em class="jxr_comment"> * Unless required by applicable law or agreed to in writing, software</em>
+<a class="jxr_linenumber" name="L12" href="#L12">12</a> <em class="jxr_comment"> * distributed under the License is distributed on an "AS IS" BASIS,</em>
+<a class="jxr_linenumber" name="L13" href="#L13">13</a> <em class="jxr_comment"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</em>
+<a class="jxr_linenumber" name="L14" href="#L14">14</a> <em class="jxr_comment"> * See the License for the specific language governing permissions and</em>
+<a class="jxr_linenumber" name="L15" href="#L15">15</a> <em class="jxr_comment"> * limitations under the License.</em>
+<a class="jxr_linenumber" name="L16" href="#L16">16</a> <em class="jxr_comment"> */</em>
+<a class="jxr_linenumber" name="L17" href="#L17">17</a> <strong class="jxr_keyword">package</strong> org.apache.commons.statistics.distribution;
+<a class="jxr_linenumber" name="L18" href="#L18">18</a>
+<a class="jxr_linenumber" name="L19" href="#L19">19</a> <strong class="jxr_keyword">import</strong> org.apache.commons.numbers.combinatorics.BinomialCoefficientDouble;
+<a class="jxr_linenumber" name="L20" href="#L20">20</a> <strong class="jxr_keyword">import</strong> org.apache.commons.numbers.combinatorics.LogBinomialCoefficient;
+<a class="jxr_linenumber" name="L21" href="#L21">21</a> <strong class="jxr_keyword">import</strong> org.apache.commons.numbers.gamma.RegularizedBeta;
+<a class="jxr_linenumber" name="L22" href="#L22">22</a>
+<a class="jxr_linenumber" name="L23" href="#L23">23</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L24" href="#L24">24</a> <em class="jxr_javadoccomment"> * Implementation of the Pascal distribution.</em>
+<a class="jxr_linenumber" name="L25" href="#L25">25</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L26" href="#L26">26</a> <em class="jxr_javadoccomment"> * <p>The Pascal distribution is a special case of the negative binomial distribution</em>
+<a class="jxr_linenumber" name="L27" href="#L27">27</a> <em class="jxr_javadoccomment"> * where the number of successes parameter is an integer.</em>
+<a class="jxr_linenumber" name="L28" href="#L28">28</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L29" href="#L29">29</a> <em class="jxr_javadoccomment"> * <p>There are various ways to express the probability mass and distribution</em>
+<a class="jxr_linenumber" name="L30" href="#L30">30</a> <em class="jxr_javadoccomment"> * functions for the Pascal distribution. The present implementation represents</em>
+<a class="jxr_linenumber" name="L31" href="#L31">31</a> <em class="jxr_javadoccomment"> * the distribution of the number of failures before \( r \) successes occur.</em>
+<a class="jxr_linenumber" name="L32" href="#L32">32</a> <em class="jxr_javadoccomment"> * This is the convention adopted in e.g.</em>
+<a class="jxr_linenumber" name="L33" href="#L33">33</a> <em class="jxr_javadoccomment"> * <a href="<a href="https://mathworld.wolfram.com/NegativeBinomialDistribution.html" target="alexandria_uri">https://mathworld.wolfram.com/NegativeBinomialDistribution.html</a>">MathWorld</a>,</em>
+<a class="jxr_linenumber" name="L34" href="#L34">34</a> <em class="jxr_javadoccomment"> * but <em>not</em> in</em>
+<a class="jxr_linenumber" name="L35" href="#L35">35</a> <em class="jxr_javadoccomment"> * <a href="<a href="https://en.wikipedia.org/wiki/Negative_binomial_distribution" target="alexandria_uri">https://en.wikipedia.org/wiki/Negative_binomial_distribution</a>">Wikipedia</a>.</em>
+<a class="jxr_linenumber" name="L36" href="#L36">36</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L37" href="#L37">37</a> <em class="jxr_javadoccomment"> * <p>The probability mass function of \( X \) is:</em>
+<a class="jxr_linenumber" name="L38" href="#L38">38</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L39" href="#L39">39</a> <em class="jxr_javadoccomment"> * <p>\[ f(k; r, p) = \binom{k+r-1}{r-1} p^r \, (1-p)^k \]</em>
+<a class="jxr_linenumber" name="L40" href="#L40">40</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L41" href="#L41">41</a> <em class="jxr_javadoccomment"> * <p>for \( r \in \{1, 2, \dots\} \) the number of successes,</em>
+<a class="jxr_linenumber" name="L42" href="#L42">42</a> <em class="jxr_javadoccomment"> * \( p \in (0, 1] \) the probability of success,</em>
+<a class="jxr_linenumber" name="L43" href="#L43">43</a> <em class="jxr_javadoccomment"> * \( k \in \{0, 1, 2, \dots\} \) the total number of failures, and</em>
+<a class="jxr_linenumber" name="L44" href="#L44">44</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L45" href="#L45">45</a> <em class="jxr_javadoccomment"> * <p>\[ \binom{k+r-1}{r-1} = \frac{(k+r-1)!}{(r-1)! \, k!} \]</em>
+<a class="jxr_linenumber" name="L46" href="#L46">46</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L47" href="#L47">47</a> <em class="jxr_javadoccomment"> * <p>is the binomial coefficient.</em>
+<a class="jxr_linenumber" name="L48" href="#L48">48</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L49" href="#L49">49</a> <em class="jxr_javadoccomment"> * <p>The cumulative distribution function of \( X \) is:</em>
+<a class="jxr_linenumber" name="L50" href="#L50">50</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L51" href="#L51">51</a> <em class="jxr_javadoccomment"> * <p>\[ P(X \leq k) = I(p, r, k + 1) \]</em>
+<a class="jxr_linenumber" name="L52" href="#L52">52</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L53" href="#L53">53</a> <em class="jxr_javadoccomment"> * <p>where \( I \) is the regularized incomplete beta function.</em>
+<a class="jxr_linenumber" name="L54" href="#L54">54</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L55" href="#L55">55</a> <em class="jxr_javadoccomment"> * @see <a href="<a href="https://en.wikipedia.org/wiki/Negative_binomial_distribution" target="alexandria_uri">https://en.wikipedia.org/wiki/Negative_binomial_distribution</a>">Negative binomial distribution (Wikipedia)</a></em>
+<a class="jxr_linenumber" name="L56" href="#L56">56</a> <em class="jxr_javadoccomment"> * @see <a href="<a href="https://mathworld.wolfram.com/NegativeBinomialDistribution.html" target="alexandria_uri">https://mathworld.wolfram.com/NegativeBinomialDistribution.html</a>">Negative binomial distribution (MathWorld)</a></em>
+<a class="jxr_linenumber" name="L57" href="#L57">57</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L58" href="#L58">58</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">class</strong> <a name="PascalDistribution" href="../../../../../org/apache/commons/statistics/distribution/PascalDistribution.html#PascalDistribution">PascalDistribution</a> <strong class="jxr_keyword">extends</strong> <a name="AbstractDiscreteDistribution" href="../../../../../org/apache/commons/statistics/distribution/AbstractDiscreteDistribution.html#AbstractDiscreteDistribution">AbstractDiscreteDistribution</a> {
+<a class="jxr_linenumber" name="L59" href="#L59">59</a> <em class="jxr_javadoccomment">/** The number of successes. */</em>
+<a class="jxr_linenumber" name="L60" href="#L60">60</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">int</strong> numberOfSuccesses;
+<a class="jxr_linenumber" name="L61" href="#L61">61</a> <em class="jxr_javadoccomment">/** The probability of success. */</em>
+<a class="jxr_linenumber" name="L62" href="#L62">62</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> probabilityOfSuccess;
+<a class="jxr_linenumber" name="L63" href="#L63">63</a> <em class="jxr_javadoccomment">/** The value of {@code log(p) * n}, where {@code p} is the probability of success</em>
+<a class="jxr_linenumber" name="L64" href="#L64">64</a> <em class="jxr_javadoccomment"> * and {@code n} is the number of successes, stored for faster computation. */</em>
+<a class="jxr_linenumber" name="L65" href="#L65">65</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> logProbabilityOfSuccessByNumOfSuccesses;
+<a class="jxr_linenumber" name="L66" href="#L66">66</a> <em class="jxr_javadoccomment">/** The value of {@code log(1-p)}, where {@code p} is the probability of success,</em>
+<a class="jxr_linenumber" name="L67" href="#L67">67</a> <em class="jxr_javadoccomment"> * stored for faster computation. */</em>
+<a class="jxr_linenumber" name="L68" href="#L68">68</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> log1mProbabilityOfSuccess;
+<a class="jxr_linenumber" name="L69" href="#L69">69</a> <em class="jxr_javadoccomment">/** The value of {@code p^n}, where {@code p} is the probability of success</em>
+<a class="jxr_linenumber" name="L70" href="#L70">70</a> <em class="jxr_javadoccomment"> * and {@code n} is the number of successes, stored for faster computation. */</em>
+<a class="jxr_linenumber" name="L71" href="#L71">71</a> <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> probabilityOfSuccessPowNumOfSuccesses;
+<a class="jxr_linenumber" name="L72" href="#L72">72</a>
+<a class="jxr_linenumber" name="L73" href="#L73">73</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L74" href="#L74">74</a> <em class="jxr_javadoccomment"> * @param r Number of successes.</em>
+<a class="jxr_linenumber" name="L75" href="#L75">75</a> <em class="jxr_javadoccomment"> * @param p Probability of success.</em>
+<a class="jxr_linenumber" name="L76" href="#L76">76</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L77" href="#L77">77</a> <strong class="jxr_keyword">private</strong> <a name="PascalDistribution" href="../../../../../org/apache/commons/statistics/distribution/PascalDistribution.html#PascalDistribution">PascalDistribution</a>(<strong class="jxr_keyword">int</strong> r,
+<a class="jxr_linenumber" name="L78" href="#L78">78</a> <strong class="jxr_keyword">double</strong> p) {
+<a class="jxr_linenumber" name="L79" href="#L79">79</a> numberOfSuccesses = r;
+<a class="jxr_linenumber" name="L80" href="#L80">80</a> probabilityOfSuccess = p;
+<a class="jxr_linenumber" name="L81" href="#L81">81</a> logProbabilityOfSuccessByNumOfSuccesses = Math.log(p) * numberOfSuccesses;
+<a class="jxr_linenumber" name="L82" href="#L82">82</a> log1mProbabilityOfSuccess = Math.log1p(-p);
+<a class="jxr_linenumber" name="L83" href="#L83">83</a> probabilityOfSuccessPowNumOfSuccesses = Math.pow(probabilityOfSuccess, numberOfSuccesses);
+<a class="jxr_linenumber" name="L84" href="#L84">84</a> }
+<a class="jxr_linenumber" name="L85" href="#L85">85</a>
+<a class="jxr_linenumber" name="L86" href="#L86">86</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L87" href="#L87">87</a> <em class="jxr_javadoccomment"> * Create a Pascal distribution.</em>
+<a class="jxr_linenumber" name="L88" href="#L88">88</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L89" href="#L89">89</a> <em class="jxr_javadoccomment"> * @param r Number of successes.</em>
+<a class="jxr_linenumber" name="L90" href="#L90">90</a> <em class="jxr_javadoccomment"> * @param p Probability of success.</em>
+<a class="jxr_linenumber" name="L91" href="#L91">91</a> <em class="jxr_javadoccomment"> * @return the distribution</em>
+<a class="jxr_linenumber" name="L92" href="#L92">92</a> <em class="jxr_javadoccomment"> * @throws IllegalArgumentException if {@code r <= 0} or {@code p <= 0} or</em>
+<a class="jxr_linenumber" name="L93" href="#L93">93</a> <em class="jxr_javadoccomment"> * {@code p > 1}.</em>
+<a class="jxr_linenumber" name="L94" href="#L94">94</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L95" href="#L95">95</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <a name="PascalDistribution" href="../../../../../org/apache/commons/statistics/distribution/PascalDistribution.html#PascalDistribution">PascalDistribution</a> of(<strong class="jxr_keyword">int</strong> r,
+<a class="jxr_linenumber" name="L96" href="#L96">96</a> <strong class="jxr_keyword">double</strong> p) {
+<a class="jxr_linenumber" name="L97" href="#L97">97</a> <strong class="jxr_keyword">if</strong> (r <= 0) {
+<a class="jxr_linenumber" name="L98" href="#L98">98</a> <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> <a name="DistributionException" href="../../../../../org/apache/commons/statistics/distribution/DistributionException.html#DistributionException">DistributionException</a>(DistributionException.NOT_STRICTLY_POSITIVE, r);
+<a class="jxr_linenumber" name="L99" href="#L99">99</a> }
+<a class="jxr_linenumber" name="L100" href="#L100">100</a> <strong class="jxr_keyword">if</strong> (p <= 0 ||
+<a class="jxr_linenumber" name="L101" href="#L101">101</a> p > 1) {
+<a class="jxr_linenumber" name="L102" href="#L102">102</a> <strong class="jxr_keyword">throw</strong> <strong class="jxr_keyword">new</strong> <a name="DistributionException" href="../../../../../org/apache/commons/statistics/distribution/DistributionException.html#DistributionException">DistributionException</a>(DistributionException.INVALID_NON_ZERO_PROBABILITY, p);
+<a class="jxr_linenumber" name="L103" href="#L103">103</a> }
+<a class="jxr_linenumber" name="L104" href="#L104">104</a> <strong class="jxr_keyword">return</strong> <strong class="jxr_keyword">new</strong> <a name="PascalDistribution" href="../../../../../org/apache/commons/statistics/distribution/PascalDistribution.html#PascalDistribution">PascalDistribution</a>(r, p);
+<a class="jxr_linenumber" name="L105" href="#L105">105</a> }
+<a class="jxr_linenumber" name="L106" href="#L106">106</a>
+<a class="jxr_linenumber" name="L107" href="#L107">107</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L108" href="#L108">108</a> <em class="jxr_javadoccomment"> * Gets the number of successes parameter of this distribution.</em>
+<a class="jxr_linenumber" name="L109" href="#L109">109</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L110" href="#L110">110</a> <em class="jxr_javadoccomment"> * @return the number of successes.</em>
+<a class="jxr_linenumber" name="L111" href="#L111">111</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L112" href="#L112">112</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">int</strong> getNumberOfSuccesses() {
+<a class="jxr_linenumber" name="L113" href="#L113">113</a> <strong class="jxr_keyword">return</strong> numberOfSuccesses;
+<a class="jxr_linenumber" name="L114" href="#L114">114</a> }
+<a class="jxr_linenumber" name="L115" href="#L115">115</a>
+<a class="jxr_linenumber" name="L116" href="#L116">116</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L117" href="#L117">117</a> <em class="jxr_javadoccomment"> * Gets the probability of success parameter of this distribution.</em>
+<a class="jxr_linenumber" name="L118" href="#L118">118</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L119" href="#L119">119</a> <em class="jxr_javadoccomment"> * @return the probability of success.</em>
+<a class="jxr_linenumber" name="L120" href="#L120">120</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L121" href="#L121">121</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> getProbabilityOfSuccess() {
+<a class="jxr_linenumber" name="L122" href="#L122">122</a> <strong class="jxr_keyword">return</strong> probabilityOfSuccess;
+<a class="jxr_linenumber" name="L123" href="#L123">123</a> }
+<a class="jxr_linenumber" name="L124" href="#L124">124</a>
+<a class="jxr_linenumber" name="L125" href="#L125">125</a> <em class="jxr_javadoccomment">/** {@inheritDoc} */</em>
+<a class="jxr_linenumber" name="L126" href="#L126">126</a> @Override
+<a class="jxr_linenumber" name="L127" href="#L127">127</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> probability(<strong class="jxr_keyword">int</strong> x) {
+<a class="jxr_linenumber" name="L128" href="#L128">128</a> <strong class="jxr_keyword">if</strong> (x <= 0) {
+<a class="jxr_linenumber" name="L129" href="#L129">129</a> <em class="jxr_comment">// Special case of x=0 exploiting cancellation.</em>
+<a class="jxr_linenumber" name="L130" href="#L130">130</a> <strong class="jxr_keyword">return</strong> x == 0 ? probabilityOfSuccessPowNumOfSuccesses : 0.0;
+<a class="jxr_linenumber" name="L131" href="#L131">131</a> }
+<a class="jxr_linenumber" name="L132" href="#L132">132</a> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">int</strong> n = x + numberOfSuccesses - 1;
+<a class="jxr_linenumber" name="L133" href="#L133">133</a> <strong class="jxr_keyword">if</strong> (n < 0) {
+<a class="jxr_linenumber" name="L134" href="#L134">134</a> <em class="jxr_comment">// overflow</em>
+<a class="jxr_linenumber" name="L135" href="#L135">135</a> <strong class="jxr_keyword">return</strong> 0.0;
+<a class="jxr_linenumber" name="L136" href="#L136">136</a> }
+<a class="jxr_linenumber" name="L137" href="#L137">137</a> <strong class="jxr_keyword">return</strong> BinomialCoefficientDouble.value(n, numberOfSuccesses - 1) *
+<a class="jxr_linenumber" name="L138" href="#L138">138</a> probabilityOfSuccessPowNumOfSuccesses *
+<a class="jxr_linenumber" name="L139" href="#L139">139</a> Math.pow(1.0 - probabilityOfSuccess, x);
+<a class="jxr_linenumber" name="L140" href="#L140">140</a> }
+<a class="jxr_linenumber" name="L141" href="#L141">141</a>
+<a class="jxr_linenumber" name="L142" href="#L142">142</a> <em class="jxr_javadoccomment">/** {@inheritDoc} */</em>
+<a class="jxr_linenumber" name="L143" href="#L143">143</a> @Override
+<a class="jxr_linenumber" name="L144" href="#L144">144</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> logProbability(<strong class="jxr_keyword">int</strong> x) {
+<a class="jxr_linenumber" name="L145" href="#L145">145</a> <strong class="jxr_keyword">if</strong> (x <= 0) {
+<a class="jxr_linenumber" name="L146" href="#L146">146</a> <em class="jxr_comment">// Special case of x=0 exploiting cancellation.</em>
+<a class="jxr_linenumber" name="L147" href="#L147">147</a> <strong class="jxr_keyword">return</strong> x == 0 ? logProbabilityOfSuccessByNumOfSuccesses : Double.NEGATIVE_INFINITY;
+<a class="jxr_linenumber" name="L148" href="#L148">148</a> }
+<a class="jxr_linenumber" name="L149" href="#L149">149</a> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">int</strong> n = x + numberOfSuccesses - 1;
+<a class="jxr_linenumber" name="L150" href="#L150">150</a> <strong class="jxr_keyword">if</strong> (n < 0) {
+<a class="jxr_linenumber" name="L151" href="#L151">151</a> <em class="jxr_comment">// overflow</em>
+<a class="jxr_linenumber" name="L152" href="#L152">152</a> <strong class="jxr_keyword">return</strong> Double.NEGATIVE_INFINITY;
+<a class="jxr_linenumber" name="L153" href="#L153">153</a> }
+<a class="jxr_linenumber" name="L154" href="#L154">154</a> <strong class="jxr_keyword">return</strong> LogBinomialCoefficient.value(n, numberOfSuccesses - 1) +
+<a class="jxr_linenumber" name="L155" href="#L155">155</a> logProbabilityOfSuccessByNumOfSuccesses +
+<a class="jxr_linenumber" name="L156" href="#L156">156</a> log1mProbabilityOfSuccess * x;
+<a class="jxr_linenumber" name="L157" href="#L157">157</a> }
+<a class="jxr_linenumber" name="L158" href="#L158">158</a>
+<a class="jxr_linenumber" name="L159" href="#L159">159</a> <em class="jxr_javadoccomment">/** {@inheritDoc} */</em>
+<a class="jxr_linenumber" name="L160" href="#L160">160</a> @Override
+<a class="jxr_linenumber" name="L161" href="#L161">161</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> cumulativeProbability(<strong class="jxr_keyword">int</strong> x) {
+<a class="jxr_linenumber" name="L162" href="#L162">162</a> <strong class="jxr_keyword">if</strong> (x < 0) {
+<a class="jxr_linenumber" name="L163" href="#L163">163</a> <strong class="jxr_keyword">return</strong> 0.0;
+<a class="jxr_linenumber" name="L164" href="#L164">164</a> }
+<a class="jxr_linenumber" name="L165" href="#L165">165</a> <strong class="jxr_keyword">return</strong> RegularizedBeta.value(probabilityOfSuccess,
+<a class="jxr_linenumber" name="L166" href="#L166">166</a> numberOfSuccesses, x + 1.0);
+<a class="jxr_linenumber" name="L167" href="#L167">167</a> }
+<a class="jxr_linenumber" name="L168" href="#L168">168</a>
+<a class="jxr_linenumber" name="L169" href="#L169">169</a> <em class="jxr_javadoccomment">/** {@inheritDoc} */</em>
+<a class="jxr_linenumber" name="L170" href="#L170">170</a> @Override
+<a class="jxr_linenumber" name="L171" href="#L171">171</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> survivalProbability(<strong class="jxr_keyword">int</strong> x) {
+<a class="jxr_linenumber" name="L172" href="#L172">172</a> <strong class="jxr_keyword">if</strong> (x < 0) {
+<a class="jxr_linenumber" name="L173" href="#L173">173</a> <strong class="jxr_keyword">return</strong> 1.0;
+<a class="jxr_linenumber" name="L174" href="#L174">174</a> }
+<a class="jxr_linenumber" name="L175" href="#L175">175</a> <strong class="jxr_keyword">return</strong> RegularizedBeta.complement(probabilityOfSuccess,
+<a class="jxr_linenumber" name="L176" href="#L176">176</a> numberOfSuccesses, x + 1.0);
+<a class="jxr_linenumber" name="L177" href="#L177">177</a> }
+<a class="jxr_linenumber" name="L178" href="#L178">178</a>
+<a class="jxr_linenumber" name="L179" href="#L179">179</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L180" href="#L180">180</a> <em class="jxr_javadoccomment"> * {@inheritDoc}</em>
+<a class="jxr_linenumber" name="L181" href="#L181">181</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L182" href="#L182">182</a> <em class="jxr_javadoccomment"> * <p>For number of successes \( r \) and probability of success \( p \),</em>
+<a class="jxr_linenumber" name="L183" href="#L183">183</a> <em class="jxr_javadoccomment"> * the mean is:</em>
+<a class="jxr_linenumber" name="L184" href="#L184">184</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L185" href="#L185">185</a> <em class="jxr_javadoccomment"> * <p>\[ \frac{r (1 - p)}{p} \]</em>
+<a class="jxr_linenumber" name="L186" href="#L186">186</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L187" href="#L187">187</a> @Override
+<a class="jxr_linenumber" name="L188" href="#L188">188</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> getMean() {
+<a class="jxr_linenumber" name="L189" href="#L189">189</a> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> p = getProbabilityOfSuccess();
+<a class="jxr_linenumber" name="L190" href="#L190">190</a> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> r = getNumberOfSuccesses();
+<a class="jxr_linenumber" name="L191" href="#L191">191</a> <strong class="jxr_keyword">return</strong> (r * (1 - p)) / p;
+<a class="jxr_linenumber" name="L192" href="#L192">192</a> }
+<a class="jxr_linenumber" name="L193" href="#L193">193</a>
+<a class="jxr_linenumber" name="L194" href="#L194">194</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L195" href="#L195">195</a> <em class="jxr_javadoccomment"> * {@inheritDoc}</em>
+<a class="jxr_linenumber" name="L196" href="#L196">196</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L197" href="#L197">197</a> <em class="jxr_javadoccomment"> * <p>For number of successes \( r \) and probability of success \( p \),</em>
+<a class="jxr_linenumber" name="L198" href="#L198">198</a> <em class="jxr_javadoccomment"> * the variance is:</em>
+<a class="jxr_linenumber" name="L199" href="#L199">199</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L200" href="#L200">200</a> <em class="jxr_javadoccomment"> * <p>\[ \frac{r (1 - p)}{p^2} \]</em>
+<a class="jxr_linenumber" name="L201" href="#L201">201</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L202" href="#L202">202</a> @Override
+<a class="jxr_linenumber" name="L203" href="#L203">203</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">double</strong> getVariance() {
+<a class="jxr_linenumber" name="L204" href="#L204">204</a> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> p = getProbabilityOfSuccess();
+<a class="jxr_linenumber" name="L205" href="#L205">205</a> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">double</strong> r = getNumberOfSuccesses();
+<a class="jxr_linenumber" name="L206" href="#L206">206</a> <strong class="jxr_keyword">return</strong> r * (1 - p) / (p * p);
+<a class="jxr_linenumber" name="L207" href="#L207">207</a> }
+<a class="jxr_linenumber" name="L208" href="#L208">208</a>
+<a class="jxr_linenumber" name="L209" href="#L209">209</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L210" href="#L210">210</a> <em class="jxr_javadoccomment"> * {@inheritDoc}</em>
+<a class="jxr_linenumber" name="L211" href="#L211">211</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L212" href="#L212">212</a> <em class="jxr_javadoccomment"> * <p>The lower bound of the support is always 0.</em>
+<a class="jxr_linenumber" name="L213" href="#L213">213</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L214" href="#L214">214</a> <em class="jxr_javadoccomment"> * @return 0.</em>
+<a class="jxr_linenumber" name="L215" href="#L215">215</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L216" href="#L216">216</a> @Override
+<a class="jxr_linenumber" name="L217" href="#L217">217</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">int</strong> getSupportLowerBound() {
+<a class="jxr_linenumber" name="L218" href="#L218">218</a> <strong class="jxr_keyword">return</strong> 0;
+<a class="jxr_linenumber" name="L219" href="#L219">219</a> }
+<a class="jxr_linenumber" name="L220" href="#L220">220</a>
+<a class="jxr_linenumber" name="L221" href="#L221">221</a> <em class="jxr_javadoccomment">/**</em>
+<a class="jxr_linenumber" name="L222" href="#L222">222</a> <em class="jxr_javadoccomment"> * {@inheritDoc}</em>
+<a class="jxr_linenumber" name="L223" href="#L223">223</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L224" href="#L224">224</a> <em class="jxr_javadoccomment"> * <p>The upper bound of the support is positive infinity except for the</em>
+<a class="jxr_linenumber" name="L225" href="#L225">225</a> <em class="jxr_javadoccomment"> * probability parameter {@code p = 1.0}.</em>
+<a class="jxr_linenumber" name="L226" href="#L226">226</a> <em class="jxr_javadoccomment"> *</em>
+<a class="jxr_linenumber" name="L227" href="#L227">227</a> <em class="jxr_javadoccomment"> * @return {@link Integer#MAX_VALUE} or 0.</em>
+<a class="jxr_linenumber" name="L228" href="#L228">228</a> <em class="jxr_javadoccomment"> */</em>
+<a class="jxr_linenumber" name="L229" href="#L229">229</a> @Override
+<a class="jxr_linenumber" name="L230" href="#L230">230</a> <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">int</strong> getSupportUpperBound() {
+<a class="jxr_linenumber" name="L231" href="#L231">231</a> <strong class="jxr_keyword">return</strong> probabilityOfSuccess < 1 ? Integer.MAX_VALUE : 0;
+<a class="jxr_linenumber" name="L232" href="#L232">232</a> }
+<a class="jxr_linenumber" name="L233" href="#L233">233</a> }
+</pre>
+<hr/>
+<div id="footer">Copyright © 2018–2022 <a href="https://www.apache.org/">The Apache Software Foundation</a>. All rights reserved.</div>
+</body>
+</html>