ndarray.native.js (2341B)
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 Float64Array = require( '@stdlib/array/float64' ); 24 var addon = require( './dcusumkbn2.native.js' ); 25 26 27 // MAIN // 28 29 /** 30 * Computes the cumulative sum of double-precision floating-point strided array elements using a second-order iterative Kahan–Babuška algorithm. 31 * 32 * @param {PositiveInteger} N - number of indexed elements 33 * @param {number} sum - initial sum 34 * @param {Float64Array} x - input array 35 * @param {integer} strideX - `x` stride length 36 * @param {NonNegativeInteger} offsetX - starting index for `x` 37 * @param {Float64Array} y - output array 38 * @param {integer} strideY - `y` stride length 39 * @param {NonNegativeInteger} offsetY - starting index for `y` 40 * @returns {Float64Array} output array 41 * 42 * @example 43 * var Float64Array = require( '@stdlib/array/float64' ); 44 * var floor = require( '@stdlib/math/base/special/floor' ); 45 * 46 * var x = new Float64Array( [ 2.0, 1.0, 2.0, -2.0, -2.0, 2.0, 3.0, 4.0 ] ); 47 * var y = new Float64Array( x.length ); 48 * var N = floor( x.length / 2 ); 49 * 50 * var v = dcusumkbn2( N, 0.0, x, 2, 1, y, 1, 0 ); 51 * // returns <Float64Array>[ 1.0, -1.0, 1.0, 5.0, 0.0, 0.0, 0.0, 0.0 ] 52 */ 53 function dcusumkbn2( N, sum, x, strideX, offsetX, y, strideY, offsetY ) { 54 var viewX; 55 var viewY; 56 if ( strideX < 0 ) { 57 offsetX += (N-1) * strideX; 58 } 59 if ( strideY < 0 ) { 60 offsetY += (N-1) * strideY; 61 } 62 viewX = new Float64Array( x.buffer, x.byteOffset+(x.BYTES_PER_ELEMENT*offsetX), x.length-offsetX ); // eslint-disable-line max-len 63 viewY = new Float64Array( y.buffer, y.byteOffset+(y.BYTES_PER_ELEMENT*offsetY), y.length-offsetY ); // eslint-disable-line max-len 64 addon( N, sum, viewX, strideX, viewY, strideY ); 65 return y; 66 } 67 68 69 // EXPORTS // 70 71 module.exports = dcusumkbn2;