ndarray.native.js (2137B)
1 /** 2 * @license Apache-2.0 3 * 4 * Copyright (c) 2018 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( './daxpy.native.js' ); 25 26 27 // MAIN // 28 29 /** 30 * Multiplies a vector `x` by a constant and adds the result to `y`. 31 * 32 * @param {PositiveInteger} N - number of elements 33 * @param {number} alpha - scalar 34 * @param {Float64Array} x - input array 35 * @param {integer} strideX - `x` stride length 36 * @param {NonNegativeInteger} offsetX - starting `x` index 37 * @param {Float64Array} y - destination array 38 * @param {integer} strideY - `y` stride length 39 * @param {NonNegativeInteger} offsetY - starting `y` index 40 * @returns {Float64Array} `y` 41 * 42 * @example 43 * var Float64Array = require( '@stdlib/array/float64' ); 44 * 45 * var x = new Float64Array( [ 1.0, 2.0, 3.0, 4.0, 5.0 ] ); 46 * var y = new Float64Array( [ 1.0, 1.0, 1.0, 1.0, 1.0 ] ); 47 * var alpha = 5.0; 48 * 49 * daxpy( x.length, alpha, x, 1, 0, y, 1, 0 ); 50 * // y => <Float64Array>[ 6.0, 11.0, 16.0, 21.0, 26.0 ] 51 */ 52 function daxpy( N, alpha, x, strideX, offsetX, y, strideY, offsetY ) { 53 var viewX; 54 var viewY; 55 if ( strideX < 0 ) { 56 offsetX += (N-1) * strideX; 57 } 58 if ( strideY < 0 ) { 59 offsetY += (N-1) * strideY; 60 } 61 viewX = new Float64Array( x.buffer, x.byteOffset+(x.BYTES_PER_ELEMENT*offsetX), x.length-offsetX ); // eslint-disable-line max-len 62 viewY = new Float64Array( y.buffer, y.byteOffset+(y.BYTES_PER_ELEMENT*offsetY), y.length-offsetY ); // eslint-disable-line max-len 63 addon( N, alpha, viewX, strideX, viewY, strideY ); 64 return y; 65 } 66 67 68 // EXPORTS // 69 70 module.exports = daxpy;