ndarray.js (1676B)
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 * @param {NonNegativeInteger} offset - starting index 35 * @returns {number} sum 36 * 37 * @example 38 * var floor = require( '@stdlib/math/base/special/floor' ); 39 * 40 * var x = [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ]; 41 * var N = floor( x.length / 2 ); 42 * 43 * var v = gnansumors( N, x, 2, 1 ); 44 * // returns 5.0 45 */ 46 function gnansumors( N, x, stride, offset ) { 47 var ix; 48 var s; 49 var i; 50 51 s = 0.0; 52 if ( N <= 0 ) { 53 return s; 54 } 55 if ( N === 1 || stride === 0 ) { 56 if ( isnan( x[ offset ] ) ) { 57 return s; 58 } 59 return x[ offset ]; 60 } 61 ix = offset; 62 for ( i = 0; i < N; i++ ) { 63 if ( isnan( x[ ix ] ) === false ) { 64 s += x[ ix ]; 65 } 66 ix += stride; 67 } 68 return s; 69 } 70 71 72 // EXPORTS // 73 74 module.exports = gnansumors;