ndarray.js (1710B)
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 float64ToFloat32 = require( '@stdlib/number/float64/base/to-float32' ); 24 25 26 // MAIN // 27 28 /** 29 * Computes the sum of single-precision floating-point strided array elements using ordinary recursive summation. 30 * 31 * @param {PositiveInteger} N - number of indexed elements 32 * @param {Float32Array} x - input array 33 * @param {integer} stride - stride length 34 * @param {NonNegativeInteger} offset - starting index 35 * @returns {number} sum 36 * 37 * @example 38 * var Float32Array = require( '@stdlib/array/float32' ); 39 * var floor = require( '@stdlib/math/base/special/floor' ); 40 * 41 * var x = new Float32Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] ); 42 * var N = floor( x.length / 2 ); 43 * 44 * var v = ssumors( N, x, 2, 1 ); 45 * // returns 5.0 46 */ 47 function ssumors( N, x, stride, offset ) { 48 var sum; 49 var ix; 50 var i; 51 52 sum = 0.0; 53 if ( N <= 0 ) { 54 return sum; 55 } 56 if ( N === 1 || stride === 0 ) { 57 return x[ offset ]; 58 } 59 ix = offset; 60 for ( i = 0; i < N; i++ ) { 61 sum = float64ToFloat32( sum + x[ ix ] ); 62 ix += stride; 63 } 64 return sum; 65 } 66 67 68 // EXPORTS // 69 70 module.exports = ssumors;