gnansumors.js (1558B)
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 // MODULES // 22 23 var isnan = require( '@stdlib/math/base/assert/is-nan' ); 24 25 26 // MAIN // 27 28 /** 29 * Computes the sum of strided array elements, ignoring `NaN` values and using ordinary recursive summation. 30 * 31 * @param {PositiveInteger} N - number of indexed elements 32 * @param {NumericArray} x - input array 33 * @param {integer} stride - stride length 34 * @returns {number} sum 35 * 36 * @example 37 * var x = [ 1.0, -2.0, NaN, 2.0 ]; 38 * var N = x.length; 39 * 40 * var v = gnansumors( N, x, 1 ); 41 * // returns 1.0 42 */ 43 function gnansumors( N, x, stride ) { 44 var ix; 45 var s; 46 var i; 47 48 s = 0.0; 49 if ( N <= 0 ) { 50 return s; 51 } 52 if ( N === 1 || stride === 0 ) { 53 if ( isnan( x[ 0 ] ) ) { 54 return s; 55 } 56 return x[ 0 ]; 57 } 58 if ( stride < 0 ) { 59 ix = (1-N) * stride; 60 } else { 61 ix = 0; 62 } 63 for ( i = 0; i < N; i++ ) { 64 if ( isnan( x[ ix ] ) === false ) { 65 s += x[ ix ]; 66 } 67 ix += stride; 68 } 69 return s; 70 } 71 72 73 // EXPORTS // 74 75 module.exports = gnansumors;