f.js (1100B)
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 /** 22 * Returns a pseudorandom number from an F distribution with parameters `d1` and `d2`. 23 * 24 * @private 25 * @param {PRNG} rchisq - PRNG for chi-square distributed numbers 26 * @param {PositiveNumber} d1 - degrees of freedom 27 * @param {PositiveNumber} d2 - degrees of freedom 28 * @returns {NonNegativeNumber} pseudorandom number 29 */ 30 function f( rchisq, d1, d2 ) { 31 var x1 = rchisq( d1 ) / d1; 32 var x2 = rchisq( d2 ) / d2; 33 return x1 / x2; 34 } 35 36 37 // EXPORTS // 38 39 module.exports = f;