logistic.js (1112B)
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 ln = require( '@stdlib/math/base/special/ln' ); 24 25 26 // MAIN // 27 28 /** 29 * Returns pseudorandom number drawn from a logistic distribution. 30 * 31 * @private 32 * @param {PRNG} rand - PRNG for uniformly distributed numbers 33 * @param {number} mu - mean 34 * @param {PositiveNumber} s - scale parameter 35 * @returns {number} pseudorandom number 36 */ 37 function logistic( rand, mu, s ) { 38 var u = rand(); 39 return mu + ( s*ln( u / (1.0-u) ) ); 40 } 41 42 43 // EXPORTS // 44 45 module.exports = logistic;