README.md (4149B)
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 # Moment-Generating Function 22 23 > [Bernoulli][bernoulli-distribution] distribution moment-generating function (MGF). 24 25 <!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. --> 26 27 <section class="intro"> 28 29 The [moment-generating function][mgf] for a [Bernoulli][bernoulli-distribution] random variable is 30 31 <!-- <equation class="equation" label="eq:bernoulli_mgf_function" align="center" raw="M_X(t) := \mathbb{E}\!\left[e^{tX}\right] = 1-p + p \exp( t )" alt="Moment-generating function (MGF) for a Bernoulli distribution."> --> 32 33 <div class="equation" align="center" data-raw-text="M_X(t) := \mathbb{E}\!\left[e^{tX}\right] = 1-p + p \exp( t )" data-equation="eq:bernoulli_mgf_function"> 34 <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@591cf9d5c3a0cd3c1ceec961e5c49d73a68374cb/lib/node_modules/@stdlib/stats/base/dists/bernoulli/mgf/docs/img/equation_bernoulli_mgf_function.svg" alt="Moment-generating function (MGF) for a Bernoulli distribution."> 35 <br> 36 </div> 37 38 <!-- </equation> --> 39 40 where `0 <= p <= 1` is the success probability. 41 42 </section> 43 44 <!-- /.intro --> 45 46 <!-- Package usage documentation. --> 47 48 <section class="usage"> 49 50 ## Usage 51 52 ```javascript 53 var mgf = require( '@stdlib/stats/base/dists/bernoulli/mgf' ); 54 ``` 55 56 #### mgf( t, p ) 57 58 Evaluates the moment-generating function ([MGF][mgf]) of a [Bernoulli][bernoulli-distribution] distribution with success probability `p`. 59 60 ```javascript 61 var y = mgf( 0.2, 0.5 ); 62 // returns ~1.111 63 64 y = mgf( 0.4, 0.5 ); 65 // returns ~1.246 66 ``` 67 68 If provided `NaN` as any argument, the function returns `NaN`. 69 70 ```javascript 71 var y = mgf( NaN, 0.0 ); 72 // returns NaN 73 74 y = mgf( 0.0, NaN ); 75 // returns NaN 76 ``` 77 78 If provided a success probability `p` outside of the interval `[0,1]`, the function returns `NaN`. 79 80 ```javascript 81 var y = mgf( -2.0, -1.0 ); 82 // returns NaN 83 84 y = mgf( 0.2, 2.0 ); 85 // returns NaN 86 ``` 87 88 #### mgf.factory( p ) 89 90 Returns a function for evaluating the [moment-generating function][mgf] of a [Bernoulli][bernoulli-distribution] distribution with parameter `p` (success probability). 91 92 ```javascript 93 var mymgf = mgf.factory( 0.8 ); 94 var y = mymgf( -0.2 ); 95 // returns ~0.855 96 ``` 97 98 </section> 99 100 <!-- /.usage --> 101 102 <!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. --> 103 104 <section class="notes"> 105 106 </section> 107 108 <!-- /.notes --> 109 110 <!-- Package usage examples. --> 111 112 <section class="examples"> 113 114 ## Examples 115 116 <!-- eslint no-undef: "error" --> 117 118 ```javascript 119 var randu = require( '@stdlib/random/base/randu' ); 120 var mgf = require( '@stdlib/stats/base/dists/bernoulli/mgf' ); 121 122 var p; 123 var t; 124 var y; 125 var i; 126 127 for ( i = 0; i < 10; i++ ) { 128 t = ( randu() * 4.0 ) - 2.0; 129 p = randu(); 130 y = mgf( t, p ); 131 console.log( 't: %d, p: %d, M_X(t;p): %d', t, p.toFixed( 4 ), y.toFixed( 4 ) ); 132 } 133 ``` 134 135 </section> 136 137 <!-- /.examples --> 138 139 <!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. --> 140 141 <section class="references"> 142 143 </section> 144 145 <!-- /.references --> 146 147 <!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. --> 148 149 <section class="links"> 150 151 [bernoulli-distribution]: https://en.wikipedia.org/wiki/Bernoulli_distribution 152 153 [mgf]: https://en.wikipedia.org/wiki/Moment-generating_function 154 155 </section> 156 157 <!-- /.links -->