mean.js (1300B)
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 // MAIN // 22 23 /** 24 * Returns the expected value of a uniform distribution. 25 * 26 * @param {number} a - minimum support 27 * @param {number} b - maximum support 28 * @returns {number} expected value 29 * 30 * @example 31 * var v = mean( 0.0, 1.0 ); 32 * // returns 0.5 33 * 34 * @example 35 * var v = mean( 4.0, 12.0 ); 36 * // returns 8.0 37 * 38 * @example 39 * var v = mean( -4.0, 4.0 ); 40 * // returns 0.0 41 * 42 * @example 43 * var v = mean( 1.0, -0.1 ); 44 * // returns NaN 45 * 46 * @example 47 * var v = mean( 2.0, NaN ); 48 * // returns NaN 49 * 50 * @example 51 * var v = mean( NaN, 2.0 ); 52 * // returns NaN 53 */ 54 function mean( a, b ) { 55 if ( 56 a >= b 57 ) { 58 return NaN; 59 } 60 return 0.5 * ( a + b ); 61 } 62 63 64 // EXPORTS // 65 66 module.exports = mean;