dnanmeanors.js (1605B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2020 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 * Computes the arithmetic mean of a double-precision floating-point strided array, ignoring `NaN` values and using ordinary recursive summation. 25 * 26 * @param {PositiveInteger} N - number of indexed elements 27 * @param {Float64Array} x - input array 28 * @param {integer} stride - stride length 29 * @returns {number} arithmetic mean 30 * 31 * @example 32 * var Float64Array = require( '@stdlib/array/float64' ); 33 * 34 * var x = new Float64Array( [ 1.0, -2.0, NaN, 2.0 ] ); 35 * var N = x.length; 36 * 37 * var v = dnanmeanors( N, x, 1 ); 38 * // returns ~0.3333 39 */ 40 function dnanmeanors( N, x, stride ) { 41 var ix; 42 var v; 43 var s; 44 var n; 45 var i; 46 47 if ( N <= 0 ) { 48 return NaN; 49 } 50 if ( N === 1 || stride === 0 ) { 51 return x[ 0 ]; 52 } 53 if ( stride < 0 ) { 54 ix = (1-N) * stride; 55 } else { 56 ix = 0; 57 } 58 s = 0.0; 59 n = 0; 60 for ( i = 0; i < N; i++ ) { 61 v = x[ ix ]; 62 if ( v === v ) { 63 s += v; 64 n += 1; 65 } 66 ix += stride; 67 } 68 return s / n; 69 } 70 71 72 // EXPORTS // 73 74 module.exports = dnanmeanors;