mode.js (1394B)
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 isnan = require( '@stdlib/math/base/assert/is-nan' ); 24 25 26 // MAIN // 27 28 /** 29 * Returns the mode of a Bernoulli distribution. 30 * 31 * ## Notes 32 * 33 * - For `p = 0.5`, the mode is either `0` or `1`. This implementation returns `0` for `p = 0.5`. 34 * 35 * @param {Probability} p - success probability 36 * @returns {NonNegativeInteger} mode 37 * 38 * @example 39 * var v = mode( 0.1 ); 40 * // returns 0 41 * 42 * @example 43 * var v = mode( 0.8 ); 44 * // returns 1 45 * 46 * @example 47 * var v = mode( 0.5 ); 48 * // returns 0 49 * 50 * @example 51 * var v = mode( 1.1 ); 52 * // returns NaN 53 * 54 * @example 55 * var v = mode( NaN ); 56 * // returns NaN 57 */ 58 function mode( p ) { 59 if ( 60 isnan( p ) || 61 p < 0.0 || 62 p > 1.0 63 ) { 64 return NaN; 65 } 66 return ( p <= 0.5 ) ? 0 : 1; 67 } 68 69 70 // EXPORTS // 71 72 module.exports = mode;