mode.js (1627B)
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 isNonNegativeInteger = require( '@stdlib/math/base/assert/is-nonnegative-integer' ); 24 var isnan = require( '@stdlib/math/base/assert/is-nan' ); 25 var floor = require( '@stdlib/math/base/special/floor' ); 26 var PINF = require( '@stdlib/constants/float64/pinf' ); 27 28 29 // MAIN // 30 31 /** 32 * Returns the mode of a binomial distribution. 33 * 34 * @param {NonNegativeInteger} n - number of trials 35 * @param {Probability} p - success probability 36 * @returns {NonNegativeInteger} mode 37 * 38 * @example 39 * var v = mode( 100, 0.1 ); 40 * // returns 10 41 * 42 * @example 43 * var v = mode( 20, 0.5 ); 44 * // returns 10 45 * 46 * @example 47 * var v = mode( 10.3, 0.5 ); 48 * // returns NaN 49 * 50 * @example 51 * var v = mode( 20, 1.1 ); 52 * // returns NaN 53 * 54 * @example 55 * var v = mode( 20, NaN ); 56 * // returns NaN 57 */ 58 function mode( n, p ) { 59 if ( 60 isnan( n ) || 61 isnan( p ) || 62 p < 0.0 || 63 p > 1.0 || 64 !isNonNegativeInteger( n ) || 65 n === PINF 66 ) { 67 return NaN; 68 } 69 return floor( ( n+1 ) * p ); 70 } 71 72 73 // EXPORTS // 74 75 module.exports = mode;