README.md (3969B)
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 # Entropy 22 23 > [Arcsine][arcsine-distribution] distribution [differential entropy][entropy]. 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 [differential entropy][entropy] (in [nats][nats]) for an [arcsine][arcsine-distribution] random variable with minimum support `a` and maximum support `b` is 30 31 <!-- <equation class="equation" label="eq:arcsine_entropy" align="center" raw="h\left( X \right) = \ln {\tfrac{\pi}{4}}" alt="Differential entropy for an arcsine distribution."> --> 32 33 <div class="equation" align="center" data-raw-text="h\left( X \right) = \ln {\tfrac{\pi}{4}}" data-equation="eq:arcsine_entropy"> 34 <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@51534079fef45e990850102147e8945fb023d1d0/lib/node_modules/@stdlib/stats/base/dists/arcsine/entropy/docs/img/equation_arcsine_entropy.svg" alt="Differential entropy for an arcsine distribution."> 35 <br> 36 </div> 37 38 <!-- </equation> --> 39 40 </section> 41 42 <!-- /.intro --> 43 44 <!-- Package usage documentation. --> 45 46 <section class="usage"> 47 48 ## Usage 49 50 ```javascript 51 var entropy = require( '@stdlib/stats/base/dists/arcsine/entropy' ); 52 ``` 53 54 #### entropy( a, b ) 55 56 Returns the [differential entropy][entropy] of an [arcsine][arcsine-distribution] distribution with minimum support `a` and maximum support `b` (in [nats][nats]). 57 58 ```javascript 59 var v = entropy( 0.0, 1.0 ); 60 // returns ~-0.242 61 62 v = entropy( 4.0, 12.0 ); 63 // returns ~1.838 64 65 v = entropy( 2.0, 8.0 ); 66 // returns ~1.55 67 ``` 68 69 If provided `NaN` as any argument, the function returns `NaN`. 70 71 ```javascript 72 var v = entropy( NaN, 2.0 ); 73 // returns NaN 74 75 v = entropy( 2.0, NaN ); 76 // returns NaN 77 ``` 78 79 If provided `a >= b`, the function returns `NaN`. 80 81 ```javascript 82 var y = entropy( 3.0, 2.0 ); 83 // returns NaN 84 85 y = entropy( 3.0, 3.0 ); 86 // returns NaN 87 ``` 88 89 </section> 90 91 <!-- /.usage --> 92 93 <!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. --> 94 95 <section class="notes"> 96 97 </section> 98 99 <!-- /.notes --> 100 101 <!-- Package usage examples. --> 102 103 <section class="examples"> 104 105 ## Examples 106 107 <!-- eslint no-undef: "error" --> 108 109 ```javascript 110 var randu = require( '@stdlib/random/base/randu' ); 111 var EPS = require( '@stdlib/constants/float64/eps' ); 112 var entropy = require( '@stdlib/stats/base/dists/arcsine/entropy' ); 113 114 var a; 115 var b; 116 var v; 117 var i; 118 119 for ( i = 0; i < 10; i++ ) { 120 a = ( randu()*10.0 ); 121 b = ( randu()*10.0 ) + a + EPS; 122 v = entropy( a, b ); 123 console.log( 'a: %d, b: %d, h(X;a,b): %d', a.toFixed( 4 ), b.toFixed( 4 ), v.toFixed( 4 ) ); 124 } 125 ``` 126 127 </section> 128 129 <!-- /.examples --> 130 131 <!-- 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. --> 132 133 <section class="references"> 134 135 </section> 136 137 <!-- /.references --> 138 139 <!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. --> 140 141 <section class="links"> 142 143 [arcsine-distribution]: https://en.wikipedia.org/wiki/Arcsine_distribution 144 145 [entropy]: https://en.wikipedia.org/wiki/Entropy_%28information_theory%29 146 147 [nats]: https://en.wikipedia.org/wiki/Nat_%28unit%29 148 149 </section> 150 151 <!-- /.links -->