arcsine.js (1263B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 The Stdlib Authors. 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 'use strict'; 20 21 // MODULES // 22 23 var pow = require( '@stdlib/math/base/special/pow' ); 24 var sin = require( '@stdlib/math/base/special/sin' ); 25 var HALF_PI = require( '@stdlib/constants/float64/half-pi' ); 26 27 28 // MAIN // 29 30 /** 31 * Returns an arcsine distributed pseudorandom number with minimum support `a` and maximum support `b`. 32 * 33 * @private 34 * @param {PRNG} rand - pseudorandom number generator 35 * @param {number} a - minimum support 36 * @param {number} b - maximum support 37 * @returns {number} pseudorandom number 38 */ 39 function arcsine( rand, a, b ) { 40 return a + ( pow( sin( HALF_PI*rand() ), 2.0 ) * ( b-a ) ); 41 } 42 43 44 // EXPORTS // 45 46 module.exports = arcsine;