discrete_uniform.js (1322B)
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 floor = require( '@stdlib/math/base/special/floor' ); 24 25 26 // MAIN // 27 28 /** 29 * Samples from a discrete uniform distribution (equal probabilities and with replacement). 30 * 31 * @private 32 * @param {ArrayLike} x - array-like object from which to sample 33 * @param {NonNegativeInteger} size - sample size 34 * @param {Function} rand - PRNG for generating uniformly distributed numbers 35 * @returns {Array} sample 36 */ 37 function discreteUniform( x, size, rand ) { 38 var pos; 39 var out; 40 var N; 41 var i; 42 43 N = x.length; 44 out = new Array( size ); 45 for ( i = 0; i < size; i++ ) { 46 pos = floor( N * rand() ); 47 out[ i ] = x[ pos ]; 48 } 49 return out; 50 } 51 52 53 // EXPORTS // 54 55 module.exports = discreteUniform;