dnanasumors.js (1792B)
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 var abs = require( '@stdlib/math/base/special/abs' ); 25 26 27 // MAIN // 28 29 /** 30 * Computes the sum of absolute values (L1 norm) of double-precision floating-point strided array elements, ignoring `NaN` values and using ordinary recursive summation. 31 * 32 * @param {PositiveInteger} N - number of indexed elements 33 * @param {Float64Array} x - input array 34 * @param {integer} stride - stride length 35 * @returns {number} sum 36 * 37 * @example 38 * var Float64Array = require( '@stdlib/array/float64' ); 39 * 40 * var x = new Float64Array( [ 1.0, -2.0, NaN, 2.0 ] ); 41 * var N = x.length; 42 * 43 * var v = dnanasumors( N, x, 1 ); 44 * // returns 5.0 45 */ 46 function dnanasumors( N, x, stride ) { 47 var sum; 48 var ix; 49 var v; 50 var i; 51 52 if ( N <= 0 ) { 53 return 0.0; 54 } 55 if ( N === 1 || stride === 0 ) { 56 if ( isnan( x[ 0 ] ) ) { 57 return 0.0; 58 } 59 return abs( x[ 0 ] ); 60 } 61 if ( stride < 0 ) { 62 ix = (1-N) * stride; 63 } else { 64 ix = 0; 65 } 66 sum = 0.0; 67 for ( i = 0; i < N; i++ ) { 68 v = x[ ix ]; 69 if ( isnan( v ) === false ) { 70 sum += abs( v ); 71 } 72 ix += stride; 73 } 74 return sum; 75 } 76 77 78 // EXPORTS // 79 80 module.exports = dnanasumors;