README.md (3743B)
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 # Quantile Function 22 23 > [Arcsine][arcsine-distribution] distribution [quantile function][quantile-function]. 24 25 <section class="intro"> 26 27 The [quantile function][quantile-function] for an [arcsine][arcsine-distribution] random variable is 28 29 <!-- <equation class="equation" label="eq:arcsine_quantile_function" align="center" raw="Q(p) = a + ( b - a ) \sin^2 \left( \tfrac{\pi}{2} p \right)" alt="Quantile function for an arcsine distribution."> --> 30 31 <div class="equation" align="center" data-raw-text="Q(p) = a + ( b - a ) \sin^2 \left( \tfrac{\pi}{2} p \right)" data-equation="eq:arcsine_quantile_function"> 32 <img src="https://cdn.jsdelivr.net/gh/stdlib-js/stdlib@591cf9d5c3a0cd3c1ceec961e5c49d73a68374cb/lib/node_modules/@stdlib/stats/base/dists/arcsine/quantile/docs/img/equation_arcsine_quantile_function.svg" alt="Quantile function for an arcsine distribution."> 33 <br> 34 </div> 35 36 <!-- </equation> --> 37 38 for `0 <= p <= 1`, where `a` is the minimum support and `b` is the maximum support. The parameters must satisfy `a < b`. 39 40 </section> 41 42 <!-- /.intro --> 43 44 <section class="usage"> 45 46 ## Usage 47 48 ```javascript 49 var quantile = require( '@stdlib/stats/base/dists/arcsine/quantile' ); 50 ``` 51 52 #### quantile( p, a, b ) 53 54 Evaluates the [quantile function][quantile-function] for an [arcsine][arcsine-distribution] distribution with parameters `a` (minimum support) and `b` (maximum support). 55 56 ```javascript 57 var y = quantile( 0.8, 0.0, 1.0 ); 58 // returns ~0.905 59 60 y = quantile( 0.5, 0.0, 10.0 ); 61 // returns ~5.0 62 ``` 63 64 If provided a probability `p` outside the interval `[0,1]`, the function returns `NaN`. 65 66 ```javascript 67 var y = quantile( 1.9, 0.0, 1.0 ); 68 // returns NaN 69 70 y = quantile( -0.1, 0.0, 1.0 ); 71 // returns NaN 72 ``` 73 74 If provided `NaN` as any argument, the function returns `NaN`. 75 76 ```javascript 77 var y = quantile( NaN, 0.0, 1.0 ); 78 // returns NaN 79 80 y = quantile( 0.0, NaN, 1.0 ); 81 // returns NaN 82 83 y = quantile( 0.0, 0.0, NaN ); 84 // returns NaN 85 ``` 86 87 If provided `a >= b`, the function returns `NaN`. 88 89 ```javascript 90 var y = quantile( 0.4, 2.0, 1.0 ); 91 // returns NaN 92 ``` 93 94 #### quantile.factory( a, b ) 95 96 Returns a function for evaluating the quantile function of an [arcsine][arcsine-distribution] distribution with parameters `a` (minimum support) and `b` (maximum support). 97 98 ```javascript 99 var myquantile = quantile.factory( 0.0, 4.0 ); 100 101 var y = myquantile( 0.8 ); 102 // returns ~3.618 103 ``` 104 105 </section> 106 107 <!-- /.usage --> 108 109 <section class="examples"> 110 111 ## Examples 112 113 <!-- eslint no-undef: "error" --> 114 115 ```javascript 116 var randu = require( '@stdlib/random/base/randu' ); 117 var quantile = require( '@stdlib/stats/base/dists/arcsine/quantile' ); 118 119 var a; 120 var b; 121 var p; 122 var y; 123 var i; 124 125 for ( i = 0; i < 25; i++ ) { 126 p = randu(); 127 a = ( randu()*20.0 ) - 20.0; 128 b = a + ( randu()*40.0 ); 129 y = quantile( p, a, b ); 130 console.log( 'p: %d, a: %d, b: %d, Q(p;a,b): %d', p.toFixed( 4 ), a.toFixed( 4 ), b.toFixed( 4 ), y.toFixed( 4 ) ); 131 } 132 ``` 133 134 </section> 135 136 <!-- /.examples --> 137 138 <section class="links"> 139 140 [arcsine-distribution]: https://en.wikipedia.org/wiki/Arcsine_distribution 141 142 [quantile-function]: https://en.wikipedia.org/wiki/Quantile_function 143 144 </section> 145 146 <!-- /.links -->