README.md (6681B)
1 <!-- 2 3 @license Apache-2.0 4 5 Copyright (c) 2018 The Stdlib Authors. 6 7 Licensed under the Apache License, Version 2.0 (the "License"); 8 you may not use this file except in compliance with the License. 9 You may obtain a copy of the License at 10 11 http://www.apache.org/licenses/LICENSE-2.0 12 13 Unless required by applicable law or agreed to in writing, software 14 distributed under the License is distributed on an "AS IS" BASIS, 15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 See the License for the specific language governing permissions and 17 limitations under the License. 18 19 --> 20 21 # Gamma 22 23 > Gamma distribution. 24 25 <section class="usage"> 26 27 ## Usage 28 29 ```javascript 30 var gamma = require( '@stdlib/stats/base/dists/gamma' ); 31 ``` 32 33 #### gamma 34 35 Gamma distribution. 36 37 ```javascript 38 var dist = gamma; 39 // returns {...} 40 ``` 41 42 The namespace contains the following distribution functions: 43 44 <!-- <toc pattern="*+(cdf|pdf|mgf|quantile)*"> --> 45 46 <div class="namespace-toc"> 47 48 - <span class="signature">[`cdf( x, alpha, beta )`][@stdlib/stats/base/dists/gamma/cdf]</span><span class="delimiter">: </span><span class="description">gamma distribution cumulative distribution function.</span> 49 - <span class="signature">[`logcdf( x, alpha, beta )`][@stdlib/stats/base/dists/gamma/logcdf]</span><span class="delimiter">: </span><span class="description">gamma distribution logarithm of cumulative distribution function (CDF).</span> 50 - <span class="signature">[`logpdf( x, alpha, beta )`][@stdlib/stats/base/dists/gamma/logpdf]</span><span class="delimiter">: </span><span class="description">gamma distribution logarithm of probability density function (PDF).</span> 51 - <span class="signature">[`mgf( t, alpha, beta )`][@stdlib/stats/base/dists/gamma/mgf]</span><span class="delimiter">: </span><span class="description">gamma distribution moment-generating function (MGF).</span> 52 - <span class="signature">[`pdf( x, alpha, beta )`][@stdlib/stats/base/dists/gamma/pdf]</span><span class="delimiter">: </span><span class="description">gamma distribution probability density function (PDF).</span> 53 - <span class="signature">[`quantile( p, alpha, beta )`][@stdlib/stats/base/dists/gamma/quantile]</span><span class="delimiter">: </span><span class="description">gamma distribution quantile function.</span> 54 55 </div> 56 57 <!-- </toc> --> 58 59 The namespace contains the following functions for calculating distribution properties: 60 61 <!-- <toc pattern="*+(entropy|kurtosis|mean|median|mode|skewness|stdev|variance)*"> --> 62 63 <div class="namespace-toc"> 64 65 - <span class="signature">[`entropy( alpha, beta )`][@stdlib/stats/base/dists/gamma/entropy]</span><span class="delimiter">: </span><span class="description">gamma distribution differential entropy.</span> 66 - <span class="signature">[`kurtosis( alpha, beta )`][@stdlib/stats/base/dists/gamma/kurtosis]</span><span class="delimiter">: </span><span class="description">gamma distribution excess kurtosis.</span> 67 - <span class="signature">[`mean( alpha, beta )`][@stdlib/stats/base/dists/gamma/mean]</span><span class="delimiter">: </span><span class="description">gamma distribution expected value.</span> 68 - <span class="signature">[`mode( alpha, beta )`][@stdlib/stats/base/dists/gamma/mode]</span><span class="delimiter">: </span><span class="description">gamma distribution mode.</span> 69 - <span class="signature">[`skewness( alpha, beta )`][@stdlib/stats/base/dists/gamma/skewness]</span><span class="delimiter">: </span><span class="description">gamma distribution skewness.</span> 70 - <span class="signature">[`stdev( alpha, beta )`][@stdlib/stats/base/dists/gamma/stdev]</span><span class="delimiter">: </span><span class="description">gamma distribution standard deviation.</span> 71 - <span class="signature">[`variance( alpha, beta )`][@stdlib/stats/base/dists/gamma/variance]</span><span class="delimiter">: </span><span class="description">gamma distribution variance.</span> 72 73 </div> 74 75 <!-- </toc> --> 76 77 The namespace contains a constructor function for creating a [gamma][gamma-distribution] distribution object. 78 79 <!-- <toc pattern="*ctor*"> --> 80 81 <div class="namespace-toc"> 82 83 - <span class="signature">[`Gamma( [alpha, beta] )`][@stdlib/stats/base/dists/gamma/ctor]</span><span class="delimiter">: </span><span class="description">gamma distribution constructor.</span> 84 85 </div> 86 87 <!-- </toc> --> 88 89 ```javascript 90 var Gamma = require( '@stdlib/stats/base/dists/gamma' ).Gamma; 91 92 var dist = new Gamma( 2.0, 4.0 ); 93 94 var y = dist.cdf( 0.5 ); 95 // returns ~0.594 96 ``` 97 98 </section> 99 100 <!-- /.usage --> 101 102 <section class="examples"> 103 104 ## Examples 105 106 <!-- TODO: better examples --> 107 108 <!-- eslint no-undef: "error" --> 109 110 ```javascript 111 var objectKeys = require( '@stdlib/utils/keys' ); 112 var gamma = require( '@stdlib/stats/base/dists/gamma' ); 113 114 console.log( objectKeys( gamma ) ); 115 ``` 116 117 </section> 118 119 <!-- /.examples --> 120 121 <section class="links"> 122 123 [gamma-distribution]: https://en.wikipedia.org/wiki/Gamma_distribution 124 125 <!-- <toc-links> --> 126 127 [@stdlib/stats/base/dists/gamma/ctor]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/ctor 128 129 [@stdlib/stats/base/dists/gamma/entropy]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/entropy 130 131 [@stdlib/stats/base/dists/gamma/kurtosis]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/kurtosis 132 133 [@stdlib/stats/base/dists/gamma/mean]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/mean 134 135 [@stdlib/stats/base/dists/gamma/mode]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/mode 136 137 [@stdlib/stats/base/dists/gamma/skewness]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/skewness 138 139 [@stdlib/stats/base/dists/gamma/stdev]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/stdev 140 141 [@stdlib/stats/base/dists/gamma/variance]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/variance 142 143 [@stdlib/stats/base/dists/gamma/cdf]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/cdf 144 145 [@stdlib/stats/base/dists/gamma/logcdf]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/logcdf 146 147 [@stdlib/stats/base/dists/gamma/logpdf]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/logpdf 148 149 [@stdlib/stats/base/dists/gamma/mgf]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/mgf 150 151 [@stdlib/stats/base/dists/gamma/pdf]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/pdf 152 153 [@stdlib/stats/base/dists/gamma/quantile]: https://www.npmjs.com/package/@stdlib/stats/tree/main/base/dists/gamma/quantile 154 155 <!-- </toc-links> --> 156 157 </section> 158 159 <!-- /.links -->